Document and Entity Information	9 Months Ended
Document and Entity Information	Sep. 30, 2018
Document And Entity Information [Abstract]
Document Type	S-4
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Trading Symbol	FLKS
Entity Registrant Name	Flex Pharma, Inc.
Entity Central Index Key	0001615219
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 12,961,126	$ 19,186,036	$ 22,416,040
Marketable securities	0	14,129,723	38,658,933
Accounts receivable	20,993	10,385	12,181
Inventory	223,519	431,891	454,132
Prepaid expenses and other current assets	478,746	777,102	925,983
Total current assets	13,684,384	34,535,137	62,467,269
Property and equipment, net	127,090	331,040	556,315
Other assets			64,800
Restricted cash	126,595	126,595	126,595
Total assets	13,938,069	34,992,772	63,214,979
Current liabilities:
Accounts payable	1,279,258	2,004,440	1,192,183
Accrued expenses and other current liabilities	1,554,679	3,712,221	2,587,573
Deferred revenue	0	72,188	88,344
Deferred rent, current portion	53,919	58,821	21,095
Total current liabilities	2,887,856	5,847,670	3,889,195
Deferred rent, net of current portion	0	39,214	8,398
Total liabilities	2,887,856	5,886,884	3,897,593
Stockholders' equity:
Preferred stock	0	0	0
Common Stock	1,807	1,780	1,678
Additional paid-in capital	142,000,936	140,184,630	135,962,935
Accumulated other comprehensive loss	0	(1,247)	(1,614)
Accumulated deficit	(130,952,530)	(111,079,275)	(76,645,613)
Total stockholders' equity	11,050,213	29,105,888	59,317,386
Total liabilities and stockholders' equity	$ 13,938,069	$ 34,992,772	$ 63,214,979

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (shares)	10,000,000	10,000,000	10,000,000
Preferred stock, shares issued (shares)	0	0	0
Preferred stock, shares outstanding (shares)	0	0	0
Common stock, par value (in usd per share)	$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares authorized (shares)	100,000,000	100,000,000	100,000,000
Common stock, shares issued (shares)	18,069,476	17,972,166	17,970,590
Common stock, shares outstanding (shares)	18,066,767	17,797,178	16,773,798

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Total revenue	$ 250,991	$ 413,601	$ 675,075	$ 991,671	$ 1,274,499	$ 1,010,663
Costs and expenses:
Cost of product revenue	91,937	148,756	355,816	373,187	506,530	662,747
Research and development	865,765	4,739,360	11,720,535	12,730,554	16,989,911	20,378,161	$ 12,749,379
Selling, general and administrative	1,959,872	4,934,937	8,651,808	14,520,596	18,503,684	19,855,987	16,464,279
Total costs and expenses	2,917,574	9,823,053	20,728,159	27,624,337	36,000,125	40,896,895	29,213,658
Loss from operations	(2,666,583)	(9,409,452)	(20,053,084)	(26,632,666)	(34,725,626)	(39,886,232)	(29,213,658)
Interest income, net	28,210	77,339	139,612	227,535	291,964	393,109	72,028
Net loss	(2,638,373)	(9,332,113)	(19,913,472)	(26,405,131)	(34,433,662)	(39,493,123)	(29,141,630)
Net loss attributable to common stockholders	$ (2,638,373)	$ (9,332,113)	$ (19,913,472)	$ (26,405,131)	$ (34,433,662)	$ (39,493,123)	$ (29,141,630)
Net loss per share attributable to common stockholders - basic and diluted (in usd per share)	$ (0.15)	$ (0.54)	$ (1.11)	$ (1.54)	$ (1.99)	$ (2.43)	$ (2.08)
Weighted-average number of common shares outstanding - basic and diluted (shares)	18,066,548	17,386,249	17,999,877	17,131,887	17,260,626	16,233,985	14,032,916
Net product revenue
Total revenue	$ 247,284	$ 407,241	$ 664,955	$ 978,221	$ 1,260,973	$ 989,918
Other revenue
Total revenue	$ 3,707	$ 6,360	$ 10,120	$ 13,450	$ 13,526	$ 20,745

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (2,638,373)	$ (9,332,113)	$ (19,913,472)	$ (26,405,131)	$ (34,433,662)	$ (39,493,123)	$ (29,141,630)
Other comprehensive gain (loss):
Unrealized gain (loss) on available-for-sale securities	0	4,305	1,247	303	367	23,040	(24,654)
Comprehensive loss	$ (2,638,373)	$ (9,327,808)	$ (19,912,225)	$ (26,404,828)	$ (34,433,295)	$ (39,470,083)	$ (29,166,284)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY - USD ($)	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Series A Preferred Stock	Series A Preferred Stock Preferred Stock	Series A Preferred Stock Common Stock	Series A Preferred Stock Additional Paid-In Capital	Series B Preferred Stock	Series B Preferred Stock Preferred Stock	Series B Preferred Stock Common Stock	Series B Preferred Stock Additional Paid-In Capital
Preferred stock, shares outstanding, beginning balance at Dec. 31, 2014		0						15,775,221				14,078,647
Equity, beginning balance at Dec. 31, 2014	$ (6,538,340)	$ 0	$ 221	$ 1,472,299	$ 0	$ (8,010,860)		$ 15,637,032				$ 25,394,135
Common stock, shares outstanding, beginning balance at Dec. 31, 2014			2,215,711
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of preferred stock to common stock (shares)								(15,775,221)	3,683,637			(14,078,647)	3,287,471
Conversion of preferred stock to common stock							$ 15,637,032	$ (15,637,032)	$ 368	$ 15,636,664	$ 25,394,135	$ (25,394,135)	$ 329	$ 25,393,806
Issuance of stock/IPO proceeds, net of issuance costs (shares)			5,491,191
Issuance of stock/IPO proceeds, net of issuance costs	$ 79,860,185		$ 549	79,859,636
Vesting of restricted common stock (shares)			1,016,328
Vesting of restricted common stock			$ 102	(102)
Issuance of common stock from option exercises (shares)	47,280		47,280
Issuance of common stock from option exercises	$ 408,321		$ 5	408,316
Stock-based compensation expense	6,597,359			6,597,359
Unrealized gain (loss) on available-for-sale securities	(24,654)				(24,654)
Net loss	(29,141,630)					(29,141,630)
Preferred stock, shares outstanding, ending balance at Dec. 31, 2015		0						0				0
Equity, ending balance at Dec. 31, 2015	$ 92,192,408	$ 0	$ 1,574	129,367,978	(24,654)	(37,152,490)		$ 0				$ 0
Common stock, shares outstanding, ending balance at Dec. 31, 2015			15,741,618
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted common stock (shares)			1,023,664
Vesting of restricted common stock			$ 102	(102)
Issuance of common stock from option exercises (shares)	8,516		8,516
Issuance of common stock from option exercises	$ 22,098		$ 2	22,096
Stock-based compensation expense	6,572,963			6,572,963
Unrealized gain (loss) on available-for-sale securities	23,040				23,040
Net loss	$ (39,493,123)					(39,493,123)
Preferred stock, shares outstanding, ending balance at Dec. 31, 2016	0	0						0				0
Equity, ending balance at Dec. 31, 2016	$ 59,317,386	$ 0	$ 1,678	135,962,935	(1,614)	(76,645,613)		$ 0				$ 0
Common stock, shares outstanding, ending balance at Dec. 31, 2016	16,773,798		16,773,798
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock/IPO proceeds, net of issuance costs (shares)	0
Vesting of restricted common stock (shares)			1,021,804
Vesting of restricted common stock	$ 0		$ 102	(102)
Issuance of common stock from option exercises (shares)	1,576		1,576
Issuance of common stock from option exercises	$ 2,632		$ 0	2,632
Stock-based compensation expense	4,219,165			4,219,165
Unrealized gain (loss) on available-for-sale securities	367				367
Net loss	$ (34,433,662)					(34,433,662)
Preferred stock, shares outstanding, ending balance at Dec. 31, 2017	0	0						0				0
Equity, ending balance at Dec. 31, 2017	$ 29,105,888	$ 0	$ 1,780	$ 140,184,630	$ (1,247)	$ (111,079,275)		$ 0				$ 0
Common stock, shares outstanding, ending balance at Dec. 31, 2017	17,797,178		17,797,178
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from option exercises (shares)	97,310
Unrealized gain (loss) on available-for-sale securities	$ 1,247
Net loss	$ (19,913,472)
Preferred stock, shares outstanding, ending balance at Sep. 30, 2018	0
Equity, ending balance at Sep. 30, 2018	$ 11,050,213
Common stock, shares outstanding, ending balance at Sep. 30, 2018	18,066,767

CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (Parenthetical)	12 Months Ended
	Dec. 31, 2015 USD ($)
Statement of Stockholders' Equity [Abstract]
Issuance costs	$ 7,998,871

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating activities
Net loss	$ (19,913,472)	$ (26,405,131)	$ (34,433,662)	$ (39,493,123)	$ (29,141,630)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	176,954	250,563	324,548	277,231	49,881
Stock-based compensation expense	1,698,323	3,266,879	4,219,165	6,572,963	6,597,359
Amortization and accretion on investments	11,537	(38,551)	(68,139)	16,161	9,523
Other non-cash items	22,274	0	1,781	3,434	4,123
Changes in operating assets and liabilities:
Restricted cash			0	240	(27)
Accounts receivable	(3,848)	(22,953)	1,796	(12,181)	0
Inventory	191,380	(79,864)	22,241	(454,132)	0
Prepaid expenses and other current assets	283,463	(130,196)	148,881	(17,409)	(538,178)
Other assets	0	64,800	64,800	(64,800)	100,103
Accounts payable	(725,182)	(274,525)	819,357	309,437	621,393
Accrued expenses and other current liabilities	(2,161,081)	1,309,611	1,124,648	746,879	1,570,216
Deferred revenue	0	9,227	(16,156)	88,344	0
Deferred rent	(44,116)	83,247	68,542	(9,475)	(18,881)
Other long term liabilities			0	(15,442)	0
Net cash used in operating activities	(20,463,768)	(21,966,893)	(27,722,198)	(32,051,873)	(20,746,118)
Investing activities
Purchases of marketable securities	(1,997,751)	(23,364,721)	(32,987,697)	(38,682,081)	(39,397,769)
Proceeds from maturities and sales of marketable securities	16,117,184	43,286,118	57,585,413	26,995,324	12,398,295
Purchases of property and equipment	0	(98,100)	(113,498)	(559,378)	(265,617)
Proceeds from sales of property and equipment	1,415	4,233	5,344	5,255	0
Net cash provided by investing activities	14,120,848	19,827,530	24,489,562	(12,240,880)	(27,265,091)
Financing activities
Proceeds from initial public offering, net of offering costs			0	0	80,435,430
Proceeds from exercise of common stock	118,010	2,047	2,632	22,098	8,321
Proceeds from early exercise of common stock			0	0	400,000
Net cash provided by financing activities	118,010	2,047	2,632	22,098	80,843,751
Net decrease in cash, cash equivalents			(3,230,004)	(44,270,655)	32,832,542
Net decrease in cash, cash equivalents and restricted cash	(6,224,910)	(2,137,316)
Cash and cash equivalents at beginning of period	19,186,036	22,416,040	22,416,040	66,686,695	33,854,153
Cash, cash equivalents and restricted cash at beginning of period	19,312,631	22,542,635	22,542,635
Cash and cash equivalents at end of period	12,961,126		19,186,036	22,416,040	66,686,695
Cash, cash equivalents and restricted cash at end of period	13,087,721	20,405,319	19,312,631	22,542,635
Supplemental cash flow information
Property and equipment purchases included in accounts payable	0	8,472
Property and equipment purchases included in accounts payable and accrued expense	$ 0	$ 7,100	0	7,100	106,680
IPO issuance costs paid in cash through December 31, 2014			$ 0	$ 0	$ 575,245

Organization and operations	9 Months Ended	12 Months Ended
Organization and operations	Sep. 30, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and operations	1. ORGANIZATION AND OPERATIONS *The Company* Flex Pharma, Inc. (the “Company”) is a biotechnology company that was focused on developing innovative and proprietary treatments for muscle cramps, spasms and spasticity associated with severe neurological conditions. In June 2018, the Company announced that it was ending its ongoing Phase 2 clinical trials of FLX-787 in patients with motor neuron disease (“MND”), primarily with amyotrophic lateral sclerosis (“ALS”), and in patients with Charcot-Marie-Tooth disease (“CMT”), due to oral tolerability concerns observed in both studies. Additionally, in June 2018, the Company initiated a process to explore a range of strategic alternatives for enhancing stockholder value, including the potential sale or merger of the Company. Wedbush PacGrow has been engaged to act as the Company’s strategic financial advisor. The Company also announced the restructuring of the organization to reduce its cost structure in order to preserve liquidity. In connection with the restructuring plan, the Company reduced its workforce by approximately 60%, with the reduction completed as of September 30, 2018. While the strategic assessment is ongoing, the Company will continue to operate with a reduced internal team that will focus their efforts on limited research and development activities and operating its consumer business, which sells HOTSHOT^®, the Company’s consumer product launched in 2016 to prevent and treat exercise-associated muscle cramps. The Company’s evaluation of strategic alternatives and its restructuring plans entails significant risks and uncertainties, including the risks and uncertainties set forth in Item 1A under the heading “Risk Factors” and Item 2 under the heading “Management’s Discussion and Analysis of Financial Condition and Results of Operations” of this Quarterly Report on Form 10-Q and in the Company’s Annual Report on Form 10-K. There can be no assurance that the Company’s evaluation of potential strategic alternatives will result in any transaction. The Company operates as two reportable segments, Consumer Operations and Drug Development. See Note 12 for additional discussion and information on the reportable segments. *Liquidity* The Company incurred a loss of $2,638,373 for the three months ended September 30, 2018, a loss of $19,913,472 for the nine months ended September 30, 2018 and had an accumulated deficit of $130,952,530 as of September 30, 2018. The Company had unrestricted cash and cash equivalents of $12,961,126 at September 30, 2018. The Company’s operating plan assumes limited research and development activities and that the Consumer Operations segment will continue to sell HOTSHOT. In the event that the Company does not complete a sale or merger, the Company (i) may elect to pursue a dissolution and liquidation of the Company or (ii) may continue to market HOTSHOT and operate its consumer business. If the Company dissolves and liquidates, the Company’s common stockholders may lose their entire investment. The amount of assets available for distribution to the Company’s stockholders will depend heavily on the timing of such liquidation as well as the amount of cash that will be needed for commitments and contingent liabilities. Based on the Company’s operating plan, the Company believes that its existing cash and cash equivalents will be sufficient to allow the Company to fund its current operating plan for at least 12 months from the date the financial statements are issued. The Company cannot predict the outcome of its strategic assessment or whether and to what extent it will resume drug development activities for FLX-787 or other drug product candidates and to what extent it will promote and sell HOTSHOT or other consumer products in the future. Accordingly, it is difficult to predict future cash needs. Management does expect the Company to incur losses for the foreseeable future. The Company’s ability to achieve profitability in the future is dependent upon achieving a level of revenues adequate to support the Company’s cost structure. The Company may never achieve profitability, and unless and until it does, the Company will continue to need to raise additional capital. If the Company raises funds through the issuance of additional equity, whether through private placements or additional public offerings, such an issuance would dilute the stockholders’ ownership in the Company. There can be no assurances, however, that additional funding will be available on terms acceptable to the Company, or at all.	1. ORGANIZATION AND OPERATIONS *The Company* Flex Pharma, Inc. (the “Company”) is a biotechnology company that is developing innovative and proprietary treatments for muscle cramps, spasms and spasticity associated with severe neurological conditions and exercise-associated muscle cramps. The Company’s lead drug product candidate, FLX-787, is currently being studied in an exploratory Phase 2 clinical trial in Australia in patients with multiple sclerosis, or MS, and in two Phase 2 clinical trials in the United States. One Phase 2 clinical trial in the United States is in patients with motor neuron disease, or MND, primarily with amyotrophic lateral sclerosis, or ALS, who suffer from muscle cramps. FLX-787 is being developed for ALS under fast track designation which was granted by the Food and Drug Administration in July 2017. The other Phase 2 clinical trial in the United States is in patients with Charcot-Marie-Tooth disease, or CMT, who suffer from muscle cramps. In 2016, the Company launched its consumer product, HOTSHOT^®, to prevent and treat exercise-associated muscle cramps. FLX-787, HOTSHOT and the Company’s other drug product candidates are based on a mechanism of action the Company describes as chemical neurostimulation. The Company believes chemical neurostimulation to be a process in which a molecule, such as FLX-787, acts topically on the surfaces of the mouth, throat, esophagus and stomach to produce a sensory signal by activating nerves in those tissues. That signal is thought to ultimately result in a beneficial effect. Specifically, the Company’s product candidates activate certain receptors known as transient receptor potential ion channels in primary sensory neurons producing a signal believed to inhibit neuronal circuits and thereby reduce hyperexcitability in the neurons that fire muscles. Reduced alpha-motor neuron hyperexcitability in spinal cord circuits is thought to suppress repetitive firing of alpha-motor neurons, thereby preventing or reducing muscle cramps and spasms, and potentially reducing reflex hyperexcitability and therefore spasticity. The Company operates as two reportable segments, Consumer Operations and Drug Development. See Note 15 for additional discussion and information on the Company’s reportable segments. The Company is subject to risks common to companies in the biotechnology and consumer products industries, including, but not limited to, risks of failure of pre-clinical studies and clinical trials, the need to obtain marketing approval for its drug product candidates, the need to successfully commercialize and gain market acceptance of its drug product candidates and its consumer products, dependence on key personnel, protection of proprietary technology, compliance with government regulations and development by competitors of alternative products. In February 2015, the Company sold 5,491,191 shares of common stock (inclusive of 91,191 shares of common stock sold by the Company pursuant to the exercise of an overallotment option granted to the underwriters in connection with the offering) through an underwritten initial public offering (“IPO”) at a price of $16.00 per share. The aggregate net proceeds received by the Company from the offering were approximately $79,900,000, after deducting underwriting discounts and commissions and offering expenses payable by the Company of approximately $8,000,000 (See Note 2). *Liquidity* The Company has incurred an accumulated deficit of $111,079,275 from February 26, 2014 (inception) through December 31, 2017, and will require substantial additional capital to fund its research and development and expenses related to its consumer brand and HOTSHOT. The Company had cash, cash equivalents and marketable securities of $33,315,759 at December 31, 2017. The Company’s operating plan assumes: (1) the efforts of the Company’s Drug Development segment are focused on the support and completion of current clinical trials; (2) reduced spending, compared to the prior year, by the Consumer Operations segment, including reduced marketing spend; and (3) limited headcount additions and corporate expenditures. Based on the Company’s implemented operating plan, the Company believes that its existing cash, cash equivalents and marketable securities will be sufficient to allow the Company to fund its current operating plan for at least 12 months from the date the financial statements are issued. Management expects the Company to incur a loss for the foreseeable future. The Company’s ability to achieve profitability in the future is dependent upon the successful development, approval and commercialization of its drug product candidates, and achieving a level of revenues adequate to support the Company’s cost structure. The Company may never achieve profitability, and unless and until it does, the Company will continue to need to raise additional capital. Management intends to fund future operations through additional private or public debt or equity offerings, and may seek additional capital through arrangements with collaborators or from other sources. There can be no assurances, however, that additional funding will be available on terms acceptable to the Company, or at all. If the Company is unable to raise additional capital in sufficient amounts or on acceptable terms, the Company may have to significantly delay, scale back or discontinue the development or commercialization of one or more of its drug product candidates or sell or license assets in the Drug Development and Consumer Operations segments.

Summary of significant accounting policies

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Accounting Policies [Abstract]

Summary of significant accounting policies

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENT ACCOUNTING PRONOUNCEMENTS

The accompanying unaudited condensed consolidated financial statements reflect the application of certain significant accounting policies as described below and elsewhere in these notes to the condensed consolidated financial statements. As of September 30, 2018, the Company’s significant accounting policies, which are detailed in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 (the “2017 10-K”), have not changed, other than as noted below.

Accounts receivable and allowance for doubtful accounts

Accounts receivable are stated at their carrying values, net of any allowances for doubtful accounts. Accounts receivable consist primarily of amounts due from specialty retailers and sports teams, for which collection is probable based on the customer’s intent and ability to pay. Receivables are evaluated for collection probability on a regular basis and an allowance for doubtful accounts is recorded, if necessary. No allowance for doubtful accounts was deemed necessary at September 30, 2018 or December 31, 2017.

Restricted cash

The Company has restricted cash in the form of a letter of credit it maintains as a security deposit on the lease of its office space in Boston, Massachusetts.

Advertising expense

Advertising expense consists of media and production costs related to print and digital advertising. All advertising is expensed as incurred. Total advertising expenses are included in selling, general and administrative expenses in the condensed consolidated statement of operations, and were approximately $20,000 and $792,000 for the three and nine months ended September 30, 2018 and approximately $1,158,000 and $3,073,000 for the three and nine months ended September 30, 2017.

Shipping and handling costs

Shipping and handling costs related to the movement of inventory to the Company’s co-packer and from the co-packer to the Company’s third-party warehousing and fulfillment partners are capitalized as inventory and expensed as cost of product revenue when revenue is recognized. Shipping and handling costs to move finished goods from the Company’s third-party warehousing and fulfillment partners to customer locations are included in selling, general and administrative expenses in the condensed consolidated statement of operations, and were approximately $27,000 and $81,000 for the three and nine months ended September 30, 2018, and approximately $64,000 and $145,000 for the three and nine months ended September 30, 2017.

Restructuring-related costs

The Company records employee termination costs in accordance with Accounting Standards Codification (“ASC”) Topic 712, “Compensation—Nonretirement and Postemployment Benefits” (ASC 712), if the termination benefits are paid as part of an ongoing benefit arrangement, which includes benefits provided as part of the Company’s established severance policy or as part of an executive employment agreement. The Company accrues employee termination costs associated with an on-going benefit arrangement if the obligation is attributable to prior services rendered, the rights to the benefits have vested, the payment is probable and the Company can reasonably estimate the liability. The Company accounts for employee termination benefits that represent a one-time benefit in accordance with ASC Topic 420, “Exit or Disposal Cost Obligations” (ASC 420). Upon communication of the termination to the employee, the Company expenses these costs over the employee’s future service period, if any.

Restructuring-related costs are recorded within research and development expenses and selling, general and administrative expenses on the Company’s condensed consolidated statement of operations. Liabilities associated with the Company’s restructuring activities are recorded as a component of accrued expenses and other current liabilities on its condensed consolidated balance sheet. See Note 7 for additional information on the Company’s current restructuring plan.

Unaudited interim financial information

Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. Accordingly, these interim condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the 2017 10-K.

The condensed consolidated financial statements as of September 30, 2018, for the three and nine months ended September 30, 2018 and 2017, and the related information contained within the notes to the condensed consolidated financial statements, are unaudited. The unaudited condensed consolidated financial statements have been prepared on the same basis as annual audited consolidated financial statements, and in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s condensed consolidated financial position as of September 30, 2018, and the statements of operations, comprehensive loss and cash flows for the three and nine month periods ended September 30, 2018 and 2017. The results for the three and nine months ended September 30, 2018 are not necessarily indicative of results to be expected for the year ending December 31, 2018, or any other future annual or interim periods.

Basis of presentation and use of estimates

The accompanying condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the ASC and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company’s management evaluates its estimates, which include, but are not limited to, estimates related to clinical study accruals, estimates related to inventory realizability, stock-based compensation expense and amounts of expenses during the reported period. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions.

Principles of consolidation

The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries: TK Pharma, Inc., a Massachusetts Securities Corporation, and Flex Innovation Group LLC, a Delaware limited liability company, which contains the Company’s consumer-related operations. All significant intercompany balances and transactions have been eliminated in consolidation.

Recent accounting pronouncements

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (“ASC 606”). ASC 606 supersedes the revenue recognition requirements in ASC Topic 605, Revenue Recognition (“ASC 605”) and requires entities to recognize revenue when control of the promised goods or services is transferred to customers at an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. The Company adopted ASC 606 as of January 1, 2018 using the modified retrospective transition method. See Note 3 for further details.

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The ASU requires lessees to recognize the assets and liabilities on their balance sheet for the rights and obligations created by most leases and continue to recognize expenses on their income statements over the lease term. It will also require disclosures designed to give financial statement users information on the amount, timing and uncertainty of cash flows arising from leases.

In July 2018, the FASB issued ASU No. 2018-10, Codification Improvements to Topic 842, Leases. This ASU is intended to clarify or correct unintended application of the guidance outlined in ASU No. 2016-02. In July 2018, the FASB issued ASU No. 2018-11, Leases (Topic 842): Targeted Improvements. This ASU is intended to address comparative reporting requirements for initial adoption. The guidance is effective for annual reporting periods beginning after December 15, 2018, and interim periods within those years. Early adoption is permitted. While the Company is currently evaluating the impact this standard will have on its consolidated financial statements, the Company expects that upon adoption, it will recognize right-of-use assets and lease liabilities and those amounts could be material.

In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The update amends the guidance in ASU Topic 230 and clarifies how entities should classify certain cash receipts and cash payments on the statement of cash flows with the objective of reducing the existing diversity in practice related to eight specific cash flow issues. The Company adopted ASU No. 2016-15 in the first quarter of 2018, retrospectively. The adoption of ASU No. 2016-15 did not have a significant impact on the consolidated financial statements.

In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows, which amends ASU Topic 230. This update requires entities to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. As a result, entities are no longer required to present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. When cash, cash equivalents, restricted cash and restricted cash equivalents are presented in more than one line item on the balance sheet, the new guidance requires a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheet. The Company adopted ASU No. 2016-18 in the first quarter of 2018, retrospectively, resulting in a change to the presentation of restricted cash on the condensed consolidated statement of cash flows.

The following table provides a reconciliation of cash and cash equivalents and restricted cash reported within the condensed consolidated balance sheets that sum to the total of such amounts in the condensed consolidated statements of cash flows:


	September 30, 2018		December 31, 2017
Cash and cash equivalents	$	12,961,126	$	19,186,036
Restricted cash		126,595		126,595

Cash, cash equivalents and restricted cash shown on the condensed consolidated statement of cash flows	$	13,087,721	$	19,312,631

In May 2017, the FASB issued ASU No. 2017-09, Stock Compensation (Topic 718): Scope of Modification Accounting, to provide clarity and reduce diversity in practice, cost and complexity when applying the guidance of Topic 718. The guidance is effective for fiscal years beginning after December 15, 2017 and interim periods within those years. Early adoption is permitted and the guidance should be applied prospectively. The Company adopted ASU No. 2017-09 in the first quarter of 2018, which did not impact the Company’s condensed consolidated financial statements or disclosures.

In June 2018, the FASB issued ASU No. 2018-07, Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting (“ASU No. 2018-07”). This ASU is intended to simplify aspects of share-based compensation issued to non-employees by making the guidance consistent with the accounting for employee share-based compensation. The guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within that year. Early adoption is permitted, but not before an entity has adopted ASC 606, and the guidance should be applied using a modified retrospective transition approach. The Company early adopted ASU No. 2018-07 on July 1, 2018 and revalued its unvested nonemployee awards as of the July 1, 2018 adoption date. The adoption did not have a material impact on the condensed consolidated financial statements and therefore a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year was not required.

In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. This ASU modifies the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement. The guidance is effective for annual reporting periods beginning after December 15, 2019, and interim periods within those years. Early adoption is permitted. The Company is currently evaluating the impact of ASU No. 2018-13 on its consolidated financial statements and disclosures.

The Company believes that the impact of other recently issued standards that are not yet effective will not have a material effect on its consolidated financial position or results of operations upon adoption.

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of presentation and use of estimates

The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company’s management evaluates its estimates, which include, but are not limited to, estimates related to inventory write-offs, clinical study accruals, stock-based compensation expense, and amounts of expenses during the reported period. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions.

Prior to the Company’s IPO, the Company utilized significant estimates and assumptions in determining the fair value of its common stock. The Company utilized various valuation methodologies in accordance with the framework of the 2004 and 2013 American Institute of Certified Public Accountants Technical Practice Aids, Valuation of Privately-Held Company Equity Securities Issued as Compensation, to estimate the fair value of its common stock. Each valuation methodology included estimates and assumptions that required the Company’s judgment. These estimates and assumptions included a number of objective and subjective factors, including external market conditions affecting the biotechnology industry sector, the prices at which the Company sold shares of preferred stock, the superior rights and preferences of securities senior to the Company’s common stock at the time and the likelihood of achieving a liquidity event, such as an initial public offering or a sale of the Company. Significant changes to the key assumptions used in the valuations could have resulted in different fair values of common stock at each valuation date and may have materially affected the financial statements.

Principles of consolidation

The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries: TK Pharma, Inc., a Massachusetts Securities Corporation, and Flex Innovation Group LLC, a Delaware limited liability company, which contains the Company’s consumer-related operations. All significant intercompany balances and transactions have been eliminated in consolidation.

Concentration of risk

The Company outsources the manufacture of HOTSHOT to a single co-packer that produces bottled finished goods. The Company also sources certain raw materials from sole suppliers. A disruption in the supply of materials or the production of finished goods could significantly impact the Company’s revenues in the future as alternative sources of raw materials and co-packing may not be available at commercially reasonable rates or within a reasonably short period of time.

Segment information

Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and assess performance. The Company and the Company’s chief operating decision maker, the Company’s Chief Executive Officer, view the Company’s operations and manage its business as two operating segments, Drug Development and Consumer Operations (see Note 15). The Company operates in one geographic segment, the United States.

Concentrations of credit risk and off-balance sheet risk

Cash, cash equivalents and marketable securities are financial instruments that potentially subject the Company to concentrations of credit risk. The Company’s cash, cash equivalents and marketable securities are held in accounts at financial institutions that management believes are creditworthy. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to any significant credit risk on these funds. The Company has no financial instruments with off-balance sheet risk of loss.

Revenue

Revenue is comprised of net product revenue and other revenue. Net product revenue includes sales of HOTSHOT finished goods to e-commerce customers, specialty retailers and sports teams. Other revenue consists of payments made by customers for expedited shipping and handling, which the Company began offering during the third quarter of 2016. Revenue is recognized when persuasive evidence of an arrangement exists, delivery of the product has occurred, the sales price is fixed or determinable and collectability is reasonably assured. For sales through September 30, 2016, the Company issued refunds to e-commerce customers, upon request, within 21 days of shipment. When the Company began selling HOTSHOT on a third-party e-commerce website in October 2016, the refund period and related deferral period increased, as the Company began offering refunds to e-commerce customers, upon request, within 30 days of delivery, for purchases subsequent to September 30, 2016. As the Company currently does not have adequate history to accurately estimate refunds, all e-commerce sales, and their related costs, are deferred and revenue is recognized once the refund period lapses. This deferral represents total deferred revenue presented on the Company’s consolidated balance sheet. For specialty retailers and sports teams, the Company does not offer a right of return or refund and revenue is recognized at the time products are delivered to customers.

Discounts provided to customers are accounted for as a reduction of product revenue, and were approximately $278,000 and $135,000 for the years ended December 31, 2017 and December 31, 2016, respectively. There were no such discounts in 2015 as the Company had not yet launched HOTSHOT.

Net product revenue and other revenue are presented net of taxes collected from customers and remitted to governmental authorities.

The Company had no customers that represented greater than 10% of total revenue during the year ended December 31, 2017 or during the year ended December 31, 2016. All revenue was generated from sales within the United States.

Accounts receivable and allowance for doubtful accounts

Accounts receivable are stated at their carrying values, net of any allowances for doubtful accounts. Accounts receivable consist primarily of amounts due from specialty retailers and sports teams, for which collectability is reasonably assured. Receivables are evaluated for collectability on a regular basis and an allowance for doubtful accounts is recorded, if necessary. No allowance for doubtful accounts was deemed necessary at December 31, 2017 and December 31, 2016.

Cost of product revenue

Cost of product revenue includes the cost of raw materials utilized to produce HOTSHOT, co-packing fees, repacking fees, in-bound freight charges and warehouse and transportation costs incurred to bring HOTSHOT finished goods to salable condition. All other costs incurred after this condition is met are considered selling costs and included in selling, general and administrative expenses. Cost of product revenue also includes write-offs for inventory that has become obsolete, has a cost basis in excess of its estimated realizable value, or exceeds projected sales, as well as depreciation expense related to manufacturing equipment purchased to support production and royalty amounts payable to certain of the Company’s founders on HOTSHOT sales.

Inventory

The Company launched HOTSHOT in the second quarter of 2016 and began capitalizing inventory costs associated with HOTSHOT in the first quarter of 2016, when it was determined that the inventory costs had probable future economic benefit. Inventory is stated at the lower of cost or estimated net realizable value, on a first-in, first-out (“FIFO”) basis.

The Company outsources the manufacture of HOTSHOT to a co-packer. Inventory at December 31, 2017 includes raw materials available for future production runs, as well as finished goods.

The Company periodically analyzes its inventory levels and writes down inventory that has become obsolete, has a cost basis in excess of its estimated realizable value, or exceeds projected sales. Estimates of excess inventory consider factors such as inventory levels, production requirements, projected sales and the estimated shelf-lives of inventory components. Inventory write-offs are recorded as a component of cost of product revenue.

Advertising expense

Advertising expense consists of media and production costs related to print and digital advertising. All advertising is expensed as incurred. Total advertising expenses are included in selling, general and administrative and were approximately $3,566,000 and $2,936,000 for the years ended December 31, 2017 and December 31, 2016, respectively. There were no such costs in 2015 as the Company had not yet launched HOTSHOT.

Shipping and handling costs

Shipping and handling costs related to the movement of inventory to the Company’s co-packer and from the co-packer to the Company’s third-party warehousing and fulfillment partners is capitalized as inventory and expensed as a cost of product revenue when revenue is recognized. Shipping and handling costs to move finished goods from the Company’s warehousing and third-party fulfillment partners to customer locations are included in selling, general and administrative expense in the consolidated statement of operations, and were approximately $261,000 and $170,000 for the years ended December 31, 2017 and December 31, 2016, respectively. There were no such costs in 2015 as the Company had not yet launched HOTSHOT.

Property and equipment

Property and equipment is stated at cost, less accumulated depreciation. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed to operations as incurred, while costs of major additions and betterments are capitalized. Upon disposal, the related cost and accumulated depreciation is removed from the accounts and any resulting gain or loss is included in the results of operations. Depreciation is recorded, once assets are placed in service, using the straight-line method over the estimated useful lives of the respective assets, which are as follows:


Asset type		Estimated useful life
Computers and computer equipment		3 years
Laboratory equipment		3 years
Manufacturing equipment		3 years
Website development costs		1-2 years

Impairment of long-lived assets

The Company evaluates long-lived assets for potential impairment when events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Recoverability is measured by comparing the book values of the assets to the expected future net undiscounted cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the book value of the assets exceed their fair value. The Company has not recognized any impairment losses through December 31, 2017.

Research and development expense

Research and development costs are charged to expense as incurred in performing research and development activities. The costs include employee compensation costs, clinical study costs, external consultant costs, regulatory costs and facilities and overhead costs. Facilities and overhead costs primarily include the allocation of insurance, rent, utility and office-related expenses attributable to research and development personnel. The Company records payments made to outside vendors in advance of services performed or goods being delivered for use in research and development activities as prepaid expenses, which are expensed as services are performed or goods are delivered.

Stock-based compensation expense

The Company accounts for its stock-based compensation awards to employees and directors in accordance with FASB ASC Topic 718, Compensation – Stock Compensation (“ASC 718”). ASC 718 requires all stock-based payments to employees, including grants of employee stock options, to be recognized in the statement of operations based on their grant date fair values. Compensation expense related to awards to employees with service conditions is recognized on a straight-line basis based on the grant date fair value over the associated service period of the award, which is generally the vesting term. Compensation expense related to awards to employees with performance conditions is recognized based on grant date fair value over the remaining service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the relative satisfaction of the performance conditions as of the reporting date. The Company accounts for stock-based compensation arrangements with non-employees based upon the fair value of the consideration received or the equity instruments issued, whichever is more reliably measurable, in accordance with the provisions of FASB ASC Topic 505-50, Equity-Based Payments to Non-Employees. The measurement date for non-employee awards is generally the date performance of services required from the non-employee is complete, resulting in periodic adjustments to stock-based compensation expense during the vesting period for changes in the fair value of the awards. Stock-based compensation costs for non-employee service awards are recognized as services are provided, which is generally the vesting period, on a straight-line basis. The unvested portion of the awards is subject to re-measurement over the vesting period.

The Company estimates the fair value of its stock options using the Black-Scholes option pricing model, which requires the input of subjective assumptions, including (a) the expected stock price volatility, (b) the expected term of the award, (c) the risk-free interest rate, (d) expected dividends and (e) the estimated fair value of the Company’s common stock on the measurement date. Due to the lack of significant trading history for the Company’s common stock, it has based its estimate of expected volatility on the historical volatility of a group of similar companies that are publicly traded. When selecting these public companies on which it has based its expected stock price volatility, the Company selected companies with comparable characteristics, including enterprise value, risk profiles, position within the industry, and with historical share price information sufficient to meet the expected term of the stock-based awards. The Company computes historical volatility data using the volatility for the selected companies’ shares during the equivalent period of the calculated expected term of the stock-based awards. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available. Due to the lack of Company specific historical option activity, the Company has estimated the expected term of its employee stock options using the “simplified” method, whereby, the expected term equals the arithmetic average of the vesting term and the original contractual term of the option. The expected term for non-employee awards is the remaining contractual term of the option. The risk-free interest rates are based on the U.S. Treasury securities with a maturity date commensurate with the expected term of the associated award. The Company has never paid, and does not expect to pay dividends in the foreseeable future.

Prior to adoption of ASU No. 2016-09 Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, share-based compensation expense was recognized net of estimated forfeitures, such that expense was recognized only for share-based awards that were expected to vest. A forfeiture rate was estimated annually and revised, if necessary, in subsequent periods if actual forfeitures differed from initial estimates. Upon adoption of ASU No. 2016-09 on January 1, 2017, the Company no longer applies a forfeiture rate and instead accounts for forfeitures as they occur.

Income taxes

Income taxes are recorded in accordance with FASB ASC Topic 740, Income Taxes (“ASC 740”), which provides for deferred taxes using an asset and liability approach. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial reporting and the tax reporting basis of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. The Company provides a valuation allowance against net deferred tax assets unless, based upon the available evidence, it is more likely than not that the deferred tax assets will be realized. The Company has evaluated available evidence and concluded that the Company may not realize the benefit of its deferred tax assets; therefore a valuation allowance has been established for the full amount of the deferred tax assets.

The Company accounts for uncertain tax positions in accordance with the provisions of ASC 740. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. As of December 31, 2017 and December 31, 2016, the Company did not have any significant uncertain tax positions. The Company’s practice is to recognize interest and/or penalties related to income tax matters in income tax expense.

Net loss per share attributable to common stockholders

Basic net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and dilutive common stock equivalents outstanding for the period, determined using the treasury stock method and the if-converted method, for convertible securities, if inclusion of these is dilutive.

For years ended December 31, 2017, December 31, 2016 and December 31, 2015, the Company has excluded the effects of all potentially dilutive shares from the weighted-average number of common shares outstanding as their inclusion in the computation for each period would be anti-dilutive due to the net loss per share incurred by the Company.

Comprehensive loss

Comprehensive loss is the change in equity of a company during a period from transactions and other events and circumstances, excluding transactions resulting from investments by owners and distributions to owners. Comprehensive loss includes net loss and the change in accumulated other comprehensive loss for the period. Accumulated other comprehensive loss consisted entirely of unrealized gains and losses on available-for-sale marketable securities for the years ended December 31, 2017, December 31, 2016 and December 31, 2015. See the consolidated statements of comprehensive loss for relevant disclosures.

The following tables summarize the changes in accumulated other comprehensive loss during the years ended December 31, 2017, December 31, 2016 and December 31, 2015.


Balance as of December 31, 2016	$	(1,614	)
Other comprehensive gain		367

Balance as of December 31, 2017	$	(1,247	)


Balance as of December 31, 2015	$	(24,654	)
Other comprehensive gain		23,040

Balance as of December 31, 2016	$	(1,614	)


Balance as of December 31, 2014	$	—
Other comprehensive loss		(24,654	)

Balance as of December 31, 2015	$	(24,654	)

Recent accounting pronouncements

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The ASU provides for a single comprehensive model for use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance. The accounting standard is effective for interim and annual periods beginning after December 15, 2016 with no early adoption permitted. In July 2015, the FASB deferred the effective date of this accounting update to annual periods beginning after December 15, 2017, along with an option to permit early adoption as of the original effective date. The Company is required to adopt the standard in the ASU using one of two acceptable methods: retrospectively to all prior reporting periods presented, with certain practical expedients permitted; or retrospectively with the cumulative effect of initially adopting the ASU recognized at the date of initial application. In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers, Principal versus Agent Considerations (Reporting Revenue Gross versus Net), clarifying the implementation guidance on principal versus agent considerations. Specifically, an entity is required to determine whether the nature of a promise is to provide the specified good or service itself (that is, the entity is a principal) or to arrange for the good or service to be provided to the customer by the other party (that is, the entity is an agent). The determination influences the timing and amount of revenue recognition. The effective date and transition requirements for ASU No. 2016-08 are the same as the effective date and transition requirements for ASU No. 2014-09.

The Company has evaluated the adoption impact of the guidance related to the Company’s sales of HOTSHOT. Based on evaluation of the Company’s revenue streams, the Company has determined that the timing of recognition for e-commerce sales will change by an immaterial amount, due to e-commerce refund rights. Through December 31, 2017 and prior to adoption of the new standard, since the Company does not have an adequate history to accurately estimate refunds, all e-commerce sales and related costs have been deferred and recognized once the refund period lapses. Under the new standard, the Company will estimate the amount of potential refunds and may recognize revenue related to some of these sales earlier if it is probable that a significant revenue reversal will not occur. Adoption will not have a significant impact on revenue recognition for the company’s specialty retail or sports team channels, as no right of refund or return exists.

The guidance is not expected to have a material impact to the consolidated statements of operations or balance sheets in any prior or prospective reporting period. The Company has finalized its accounting policy, and has designed and implemented necessary changes to processes and controls to allow for proper recognition, presentation and disclosure upon adoption effective in the beginning of fiscal year 2018.

In July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330). This ASU simplifies the measurement of inventory by requiring certain inventory to be measured at the lower of cost or net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The amendments in this ASU are effective for fiscal years beginning after December 15, 2016 and for interim periods therein. Subsequent measurement is unchanged for inventory measured using LIFO or the retail inventory method. The Company adopted this ASU as of March 31, 2017, which did not have a material impact on its condensed consolidated financial statements.

In February 2016, the FASB issued ASU No. 2016-02, Leases. The ASU requires lessees to recognize the assets and liabilities on their balance sheet for the rights and obligations created by most leases and continue to recognize expenses on their income statements over the lease term. It will also require disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. The guidance is effective for annual reporting periods beginning after December 15, 2018, and interim periods within those years. Early adoption is permitted. While the Company is currently evaluating the effect this standard will have on its consolidated financial statements and timing of adoption, the Company expects that upon adoption, it will recognize right-of-use assets and lease liabilities and those amounts could be material. The Company is still assessing the expected impact on our consolidated statements of operations and cash flows.

In March 2016, the FASB issued ASU No. 2016-09, Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. This ASU simplifies the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The guidance is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods. The Company adopted the new standard on January 1, 2017 and has elected to account for forfeitures as they occur. The change was applied on a modified retrospective basis with a cumulative effect adjustment to increase retained earnings by approximately $2,000, as of January 1, 2017. In addition, upon adoption of the new standard, the Company has additional deferred tax assets related to tax deductions from excess tax benefits related to the exercise of stock options. As a result, the deferred tax assets associated with net operating losses increased by approximately $42,000 in the first quarter of 2017. The amounts are offset by a corresponding increase in the valuation allowance. As such, there is no net effect on the Company’s consolidated statements of operations for the twelve months ended December 31, 2017.

In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The update amends the guidance in ASU 230 Statement of Cash Flows, and clarifies how entities should classify certain cash receipts and cash payments on the statement of cash flows with the objective of reducing the existing diversity in practice related to eight specific cash flow issues. The amendments in this update are effective for fiscal years beginning after December 15, 2017, and interim periods within those years. Early adoption is permitted. The Company does not expect the adoption of ASU 2016-15 to have a material impact on its consolidated financial statements.

In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows, which amends ASU Topic 230. This update requires entities to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. As a result, entities will no longer be required to present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. When cash, cash equivalents, restricted cash and restricted cash equivalents are presented in more than one line item on the balance sheet, the new guidance requires a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheet. Entities will also have to disclose the nature of their restricted cash and restricted cash equivalent balances. The guidance is effective for fiscal years beginning after December 15, 2017 and interim periods within those years. Early adoption is permitted. Entities are required to apply the guidance retrospectively. The new guidance will change the presentation of restricted cash in the Company’s consolidated financial statements in the first quarter of 2018.

In May 2017, the FASB issued ASU 2017-09, Stock Compensation (Topic 718): Scope of Modification Accounting, to provide clarity and reduce diversity in practice, cost and complexity when applying the guidance in Topic 718. The guidance is effective for fiscal years beginning after December 15, 2017 and interim periods within those years. Early adoption is permitted. The Company does not expect the adoption of this guidance to have a material effect on its consolidated financial statements and related disclosures.

Initial public offering

On February 3, 2015, the Company completed its IPO, whereby the Company sold 5,491,191 shares of its common stock (inclusive of 91,191 shares of common stock sold by the Company pursuant to the exercise of an overallotment option granted to the underwriters in connection with the IPO) at a price of $16.00 per share. The shares began trading on The Nasdaq Global Market on January 29, 2015. The aggregate net proceeds received by the Company from the IPO were approximately $79,900,000, after deducting underwriting discounts and commissions and other offering expenses payable by the Company. Upon the closing of the IPO, all outstanding shares of convertible preferred stock converted into 6,971,108 shares of common stock. Additionally, the Company is now authorized to issue 100,000,000 shares of common stock.

Deferred IPO issuance costs, which primarily consisted of direct incremental legal and accounting fees related to the Company’s IPO, were capitalized at December 31, 2014. Upon the closing of the IPO in February 2015, IPO issuance costs of $1,848,737, as well as underwriting discounts and commissions of $6,150,134, were offset against the IPO proceeds within additional paid-in capital.

Reverse stock split

In January 2015, the Company effected a one-for-4.2825 reverse stock split of its then issued and outstanding common stock. All share and per share amounts related to issued and outstanding common stock and outstanding options exercisable for common stock included in the Company’s consolidated financial statements and notes to consolidated financial statements have been retroactively adjusted for all periods presented to reflect the reverse stock split, including reclassifying an amount equal to the reduction in par value of common stock to additional paid-in capital. The conversion ratios of the Company’s convertible preferred stock have also been adjusted to reflect the reverse stock split.

Subsequent events

The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the consolidated financial statements for potential recognition or disclosure in the consolidated financial statements. Subsequent events have been evaluated through the date these consolidated financial statements were issued for potential recognition or disclosure in the consolidated financial statements (see Note 18).

Restricted cash	12 Months Ended
Restricted cash	Dec. 31, 2017
Receivables [Abstract]
Restricted cash	3. RESTRICTED CASH As of December 31, 2017 and December 31, 2016, the Company had $126,595 of restricted cash in the form of a letter of credit. The Company maintains this letter of credit as a security deposit on the lease of its office space in Boston, Massachusetts (see Note 9).

Fair value measurements

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair value measurements

4. FAIR VALUE MEASUREMENTS

The Company records cash equivalents and marketable securities at fair value. ASC Topic 820, Fair Value Measurements and Disclosures, established a fair value hierarchy for those instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). The hierarchy consists of three levels:

Level 1 – Unadjusted quoted prices in active markets for identical assets or liabilities.

Level 2 – Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, directly or indirectly, for substantially the full term of the asset or liability.

Level 3 – Unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability in which there is little, if any, market activity for the asset or liability at the measurement date.

The following tables summarize the cash equivalents and marketable securities measured at fair value on a recurring basis as of September 30, 2018 and December 31, 2017:


	Level 1		Level 2		Level 3		Balance as of September 30, 2018
Cash equivalents	$	2,321,614	$	—	$	—	$	2,321,614

	$	2,321,614	$	—	$	—	$	2,321,614


	Level 1		Level 2		Level 3		Balance as of December 31, 2017
Cash equivalents	$	5,046,205	$	—	$	—	$	5,046,205
Marketable securities:
U.S. government agency securities		—		8,986,259		—		8,986,259
Commercial paper		—		4,440,689		—		4,440,689
Corporate debt securities		—		702,775		—		702,775

	$	5,046,205	$	14,129,723	$	—	$	19,175,928

Cash equivalents and marketable securities have been initially valued at the transaction price and subsequently valued, at the end of each reporting period, utilizing third-party pricing services or other market observable data. The third-party pricing services utilize industry standard valuation models, including both income and market based approaches and observable market inputs to determine value. The Company’s cash equivalents consist of money market funds that are valued based on publicly available quoted market prices for identical securities as of September 30, 2018. After completing its validation procedures, the Company did not adjust or override any fair value carrying amounts as of September 30, 2018.

The carrying amounts reflected in the condensed consolidated balance sheets for cash, accounts receivable, prepaid expenses and other current assets, accounts payable, accrued expenses and other current liabilities approximate their fair values at September 30, 2018 and December 31, 2017, due to their short-term nature.

The Company evaluates transfers between levels at the end of each reporting period. There were no transfers of assets or liabilities between Level 1 and Level 2 during the nine months ended September 30, 2018 or the year ended December 31, 2017. The Company had no financial assets or liabilities that were classified as Level 3 at any time during the nine months ended September 30, 2018 or the year ended December 31, 2017.

4. FAIR VALUE MEASUREMENTS

The Company records cash equivalents and marketable securities at fair value. ASC Topic 820, Fair Value Measurements and Disclosures established a fair value hierarchy for those instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). The hierarchy consists of three levels:

Level 1 – Unadjusted quoted prices in active markets for identical assets or liabilities.

The following table summarizes the cash equivalents and marketable securities measured at fair value on a recurring basis as of December 31, 2017 and December 31, 2016:


	Level 1		Level 2		Level 3		Balance at December 31, 2017
Cash equivalents	$	5,046,205	$	—	$	—	$	5,046,205
Marketable securities:
U.S. government agency securities		—		8,986,259		—		8,986,259
Commercial paper		—		4,440,689		—		4,440,689
Corporate debt securities		—		702,775		—		702,775

	$	5,046,205	$	14,129,723	$	—	$	19,175,928


	Level 1		Level 2		Level 3		Balance at December 31, 2016
Cash equivalents	$	11,681,074	$	—	$	—	$	11,681,074
Marketable securities:
U.S. government agency securities		—		31,059,491		—		31,059,491
Commercial paper		—		6,081,202		—		6,081,202
Corporate debt securities		—		1,518,240		—		1,518,240

	$	11,681,074	$	38,658,933	$	—	$	50,340,007

Cash equivalents and marketable securities have been initially valued at the transaction price and subsequently valued, at the end of each reporting period, utilizing third-party pricing services or other market observable data. The pricing services utilize industry standard valuation models, including both income and market based approaches and observable market inputs to determine value. The majority of the Company’s cash equivalents consist of money market funds that are valued based on publicly available quoted market prices for identical securities as of December 31, 2017. After completing its validation procedures, the Company did not adjust or override any fair value carrying amounts of as of December 31, 2017.

The carrying amounts reflected in the consolidated balance sheets for cash, accounts receivable, prepaid expenses and other current assets, accounts payable, accrued expenses and other current liabilities approximate their fair values at December 31, 2017 and 2016, due to their short-term nature.

The Company evaluates transfers between levels at the end of each reporting period. There were no transfers of assets or liabilities between Level 1 and Level 2 during the year ended December 31, 2017 or during the year ended December 31, 2016. The Company had no financial assets or liabilities that were classified as Level 3 at any point during the year ended December 31, 2017 or during the year ended December 31, 2016.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Cash equivalents and marketable securities

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Cash and Cash Equivalents [Abstract]

Cash equivalents and marketable securities

5. CASH EQUIVALENTS AND MARKETABLE SECURITIES

The Company considers all highly liquid investments with maturities of three months or less when purchased to be cash equivalents. Cash equivalents as of September 30, 2018 and December 31, 2017 consisted of money market funds.

The Company held no marketable securities as of September 30, 2018. Marketable securities as of December 31, 2017 consisted of U.S. government agency securities, commercial paper and corporate debt securities. Management determines the appropriate classification of the securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. The Company classifies its marketable securities as available-for-sale pursuant to ASC 320, Investments – Debt and Equity Securities. Marketable securities are recorded at fair value, with unrealized gains and losses included as a component of accumulated other comprehensive income (loss) in stockholders’ equity and a component of total comprehensive income (loss) in the condensed consolidated statement of comprehensive loss, until realized. Realized gains and losses are included in investment income on a specific-identification basis. There were no realized gains on marketable securities during the three and nine months ended September 30, 2018, or during the three and nine months ended September 30, 2017.

The Company reviews marketable securities for other-than-temporary impairment whenever the fair value of a marketable security is less than the amortized cost and evidence indicates that a marketable security’s carrying amount is not recoverable within a reasonable period of time. Other-than-temporary impairments of investments are recognized in the consolidated statement of operations if the Company has experienced a credit loss, has the intent to sell the marketable security, or if it is more likely than not that the Company will be required to sell the marketable security before recovery of the amortized cost basis. Evidence considered in this assessment includes reasons for the impairment, compliance with the Company’s investment policy, the severity and the duration of the impairment and changes in value subsequent to the end of the period.

The Company held no marketable securities at September 30, 2018. Marketable securities at December 31, 2017 consisted of the following:


	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
As of December 31, 2017
Current (due within 1 year):
U.S. government agency securities	$	8,987,254	$	38	$	(1,033	)	$	8,986,259
Commercial paper		4,440,689		—		—			4,440,689
Corporate debt securities		703,027		—		(252	)		702,775

Total	$	14,130,970	$	38	$	(1,285	)	$	14,129,723

At December 31, 2017, the Company held six debt securities that were in an unrealized loss position, all of which had been in a continuous loss position for less than 12 months. The aggregate fair value of debt securities in an unrealized loss position was $8,191,315 at December 31, 2017. There were no individual securities that were in a significant unrealized loss position as of December 31, 2017.

At December 31, 2017, all investments held by the Company were classified as current. Investments classified as current have maturities of less than one year. Investments classified as noncurrent are those that (i) have a maturity greater than one year and (ii) management does not intend to liquidate within the next year, although these funds are available for use and therefore classified as available-for-sale.

5. CASH EQUIVALENTS AND MARKETABLE SECURITIES

The Company considers all highly liquid investments with maturities of three months or less when purchased to be cash equivalents. Cash equivalents as of December 31, 2017 and December 31, 2016 consisted of money market funds.

Marketable securities as of December 31, 2017 and December 31, 2016 consisted of corporate debt securities, commercial paper and U.S. government agency securities. Management determines the appropriate classification of the securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. The Company classifies its marketable securities as available-for-sale pursuant to ASC 320, Investments – Debt and Equity Securities. Marketable securities are recorded at fair value, with unrealized gains and losses included as a component of accumulated other comprehensive income (loss) in stockholders’ equity and a component of total comprehensive income (loss) in the consolidated statement of comprehensive income (loss), until realized. Realized gains and losses are included in investment income on a specific-identification basis. There were no realized gains on marketable securities during the year ended December 31, 2017, and there were immaterial realized gains on marketable securities during the year ended December 31, 2016.

Marketable securities at December 31, 2017 and December 31, 2016 consisted of the following:


	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
As of December 31, 2017
Current (due within 1 year):
U.S. government agency securities	$	8,987,254	$	38	$	(1,033	)	$	8,986,259
Commercial paper		4,440,689		—		—			4,440,689
Corporate debt securities		703,027		—		(252	)		702,775

Total	$	14,130,970	$	38	$	(1,285	)	$	14,129,723


	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
As of December 31, 2016
Current (due within 1 year):
U.S. government agency securities	$	31,060,710	$	2,912	$	(4,131	)	$	31,059,491
Commercial paper		6,081,202		—		—			6,081,202
Corporate debt securities		1,518,635		—		(395	)		1,518,240

Total	$	38,660,547	$	2,912	$	(4,526	)	$	38,658,933

The Company held six securities that were in an unrealized loss position at both December 31, 2017 and December 31, 2016, all of which were in a continuous loss position for less than 12 months. The aggregate fair value of securities in an unrealized loss position was $8,191,315 and $16,519,620 at December 31, 2017 and December 31, 2016, respectively. There were no individual securities that were in a significant unrealized loss position as of December 31, 2017 or December 31, 2016. The Company evaluated its securities for other-than-temporary impairment and considered the decline in market value for the securities to be primarily attributable to current economic and market conditions. The Company has the intent and ability to hold such securities until recovery. Based on this analysis, these marketable securities were not considered to be other-than-temporarily impaired as of December 31, 2017.

At December 31, 2017 and December 31, 2016, all investments held by the Company were classified as current. Investments classified as current have maturities of less than one year. Investments classified as noncurrent are those that (i) have a maturity greater than one year and (ii) management does not intend to liquidate within the next year, although these funds are available for use and therefore classified as available-for-sale.

Inventory

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Inventory Disclosure [Abstract]

Inventory

6. INVENTORY

Inventory has been recorded at cost as of September 30, 2018 and December 31, 2017. Costs capitalized at September 30, 2018 and December 31, 2017 relate to HOTSHOT finished goods, as well as raw materials available to be used for future production runs.

The following table presents inventory:


	September 30, 2018		December 31, 2017
Raw materials	$	7,240	$	17,411
Finished goods		216,279		414,480

Total inventory	$	223,519	$	431,891

In the second quarter of 2018, the Company wrote off raw materials that are not expected to be used in future production runs, as well as finished goods inventory no longer expected to be used for product sampling. In the prior year, the Company wrote off raw materials not expected to be used in future production runs and expiring finished goods not anticipated to be sold.

There were no inventory write-offs during the three months ended September 30, 2018. Write-offs totaled approximately $85,000 for the nine months ended September 30, 2018, and approximately $15,000 and $34,000 for the three and nine months ended September 30, 2017, respectively, and were included in cost of product revenue in the accompanying condensed consolidated statement of operations.

6. INVENTORY

The Company began capitalizing inventory as of March 31, 2016, when it was determined that the inventory had a probable future economic benefit. Inventory has been recorded at cost as of December 31, 2017 and December 31, 2016. Costs capitalized at December 31, 2017 and December 31, 2016 relate to HOTSHOT finished goods, as well as raw materials available to be used for future production runs.

The following table presents inventory:


	December 31, 2017		December 31, 2016
Raw materials	$	17,411	$	19,888
Finished goods		414,480		434,244

Total inventory	$	431,891	$	454,132

In the second quarter of 2017, the Company completed a production run of HOTSHOT. From the second to fourth quarter of 2017, the Company wrote off materials purchased for production that were not expected to be used in future production runs, as well as expiring finished goods. In 2016, the Company wrote off raw materials purchased for production runs of HOTSHOT that were not expected to be used in future production runs, as well as finished goods not expected to be sold based upon projected sales, estimated product shelf life, the number of units produced and production level requirements.

Write-offs totaled approximately $42,000 and $282,000 for the years ended December 31, 2017 and December 31, 2016, respectively, and are included in cost of product revenue in the accompanying consolidated statement of operations.

The cost of product revenue related to deferred revenue is capitalized and recorded as cost of product revenue at the time the revenue is recognized.

Property and equipment, net

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property and equipment, net

7. PROPERTY AND EQUIPMENT, NET

Property and equipment, net consists of the following:


	December 31, 2017			December 31, 2016
Manufacturing equipment	$	421,999		$	421,999
Computers and computer equipment		311,847			276,263
Website development costs		177,886			159,836
Laboratory equipment		13,368			13,368
Capital in progress		28,823			7,863

Total property and equipment		953,923			879,329
Accumulated depreciation		(622,883	)		(323,014	)

Property and equipment, net	$	331,040		$	556,315

Capital in progress consists of assets acquired but not yet placed into service. At December 31, 2017 capital in progress consisted of computers and computer equipment, and at December 31, 2016 capital in progress consisted of computers and website development costs.

Depreciation expense was $324,548, $277,231 and $49,881 for the years ended December 31, 2017, December 31, 2016, and December 31, 2015, respectively.

Accrued expenses and other current liabilities

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Payables and Accruals [Abstract]

Accrued expenses and other current liabilities

7. ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES

Accrued expenses and other current liabilities consisted of the following:


	September 30, 2018		December 31, 2017
Phase 2 MND and CMT clinical trial-related costs	$	609,222	$	1,850,115
Payroll and other employee-related costs		430,560		874,246
Professional fees		284,725		227,980
Restructuring-related costs		189,927		—
Other research and development-related costs		23,808		652,285
Consumer product-related costs		16,437		107,595

Total	$	1,554,679	$	3,712,221

Phase 2 MND and CMT clinical trial-related costs

In June 2018, the Company announced that it was ending its ongoing Phase 2 clinical trials of FLX-787 in MND and CMT due to oral tolerability concerns observed in both studies.

The close out of the studies resulted in increased expense during the second quarter of 2018, with the remainder of close out costs occurring in the third quarter of 2018. Accrued costs as of September 30, 2018 totaled approximately $610,000. All work for the studies was complete as of September 30, 2018. Previously, the Company expected work for the studies to take place through mid-2019.

Restructuring-related costs

In June 2018, the Company’s Board of Directors (“Board”) approved a corporate restructuring plan to reduce the Company’s cost structure. In connection with the corporate restructuring plan, the Company reduced its workforce by approximately 60%, with the reduction completed as of September 30, 2018.

Also, in June 2018, the Board approved employee retention arrangements and certain increased severance payments related to the corporate restructuring plan, to incentivize certain employees to remain with the Company through a potential sale or merger. Cash retention benefits totaling approximately $1,210,000 will be payable to these employees upon the occurrence of a change in control event, including a sale or merger of the Company. Of this total, $500,000 relates to amounts payable only upon a change in control event, and $710,000 relates to amounts payable upon a change in control event or at certain time points through early 2019 if the individuals are employed by the Company and in good standing at the date of payment, even if a change in control event has not occurred. Upon a change in control event and termination without cause, these employees will be eligible for up to approximately $1,125,000, in the aggregate, of severance benefits.

The Company records employee termination costs in accordance with ASC 712, if the termination benefits are paid as part of an ongoing benefit arrangement, which includes benefits provided as part of the Company’s established severance policy or as part of an executive employment agreement. The Company accrues employee termination costs associated with an on-going benefit arrangement if the obligation is attributable to prior services rendered, the rights to the benefits have vested, the payment is probable and the Company can reasonably estimate the liability. The Company accounts for employee termination benefits that represent a one-time benefit in accordance with ASC 420. Upon communication of the termination to the employee, the Company expenses these costs over the employee’s future service period, if any.

During the three months ended September 30, 2018, the Company recognized expense for restructuring-related activities of approximately $212,000, which is comprised of approximately $77,000 of one-time termination benefit costs for terminated employees and approximately $147,000 in retention benefits for seven retained employees who have retention bonuses not contingent on a change in control event, partially offset by approximately $12,000 recorded as a credit to termination benefits under ongoing benefit arrangements for terminated employees as certain benefit payments are no longer expected to occur. During the nine months ended September 30, 2018, the Company recognized expense for restructuring-related activities of approximately $1,130,000 which is comprised of approximately $851,000 recorded as termination benefits under ongoing benefit arrangements for terminated employees, approximately $99,000 as one-time termination benefit costs for terminated employees, approximately $165,000 in retention benefits for seven retained employees who have retention bonuses not triggered by a change in control event and approximately $15,000 of other restructuring related costs including consulting and legal fees. There are currently no assurances a change in control event will take place. The Company does not consider the payment of severance benefits for retained employees or the payment of retention benefits only payable upon a change in control to be probable for accounting purposes as of September 30, 2018. Unless and until the Company’s Board has approved a specific transaction, the Company’s probability assessment regarding a change in control event is not expected to change.

The Company expects to incur between approximately $1,173,000 and $3,353,000 in total costs for its restructuring-related activities, including approximately $1,130,000 that was recorded during the second and third quarters of 2018. Approximately $50,000 is expected to be recorded during the fourth quarter of 2018, based on the Company’s current probability assessment regarding a change in control event and termination of retained employees. The range noted above includes approximately $500,000 related to retention benefits only payable upon a change in control event and $1,125,000 of severance benefits only payable upon a change in control event and termination under certain circumstances.

The following table outlines the Company’s restructuring activities for the nine months ended September 30, 2018:


Opening balance	$	—
Charges:
Employee termination benefits		950,637
Employee retention benefits		164,813
Other		14,995
Payments		(940,518	)

Accrued restructuring balance as of September 30, 2018	$	189,927

The Company’s accrued restructuring balance as of September 30, 2018 is included as a component of accrued expenses and other current liabilities on the Company’s condensed consolidated balance sheet as of September 30, 2018. For the three months ended September 30, 2018, approximately $133,000 of the restructuring-related charges are included in research and development expenses and approximately $79,000 are included in selling, general and administrative expenses in the Company’s condensed consolidated statement of operations. For the nine months ended September 30, 2018, approximately $837,000 of the restructuring-related charges are included in research and development expenses and approximately $293,000 are included in selling, general and administrative expenses in the Company’s condensed consolidated statement of operations.

For the three months ended September 30, 2018, approximately $19,000 of the restructuring-related charges were incurred by our Consumer Operations segment, approximately $133,000 were incurred by our Drug Development segment and the remaining charges of approximately $60,000 related to corporate costs. For the nine months ended September 30, 2018, approximately $75,000 of the restructuring-related charges were incurred by our Consumer Operations segment, approximately $837,000 were incurred by our Drug Development segment and the remaining charges of approximately $218,000 related to corporate costs. The Company may incur total restructuring-related charges of up to approximately $113,000 and $1,048,000 within our Consumer Operations and Drug Development segments, respectively. The Company may incur up to $2,192,000 of corporate costs that do not relate to a reportable segment.

Litigation

On June 19, 2018, a putative class action lawsuit was filed against the Company and certain of its current executive officers in the United States District Court for the Southern District of New York, captioned Teofilina Rumaldo v. Flex Pharma, Inc., et al., Case No. 1:18-cv-05493. The complaint purports to be brought on behalf of stockholders who purchased the Company’s common stock between November 6, 2017 and June 12, 2018. The complaint generally alleges that the Company and certain of its current officers violated Sections 10(b) and/or 20(a) of the Securities Exchange Act of 1934, as amended, and Rule 10b-5 promulgated thereunder by making allegedly false and misleading statements or omissions regarding the Company’s business, operational and compliance policies. Specifically, the complaint alleges that the Company overstated the viability and approval prospects for its product candidate FLX-787 for the treatment of MND and CMT and, as a result, the Company’s public statements were materially false and misleading at all relevant times. The complaint seeks unspecified damages, attorneys’ fees and other costs. The court-appointed lead plaintiff has until December 10, 2018, to file an amended complaint. The Company denies any allegations of wrongdoing and intends to vigorously defend against this lawsuit. The Company is unable, however, to predict the outcome of this matter at this time and has not accrued any expense related to this lawsuit as of September 30, 2018.

8. ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES

Accrued expenses and other current liabilities consist of the following:


	December 31, 2017		December 31, 2016
Research and development costs	$	2,502,400	$	938,665
Payroll and employee-related costs		874,246		1,453,665
Professional fees		227,980		153,219
Consumer product-related costs		107,595		42,024

Total	$	3,712,221	$	2,587,573

Commitments and contingencies

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Commitments and contingencies

9. COMMITMENTS AND CONTINGENCIES

Lease commitments

On April 29, 2014, the Company leased office space in Boston, Massachusetts that was scheduled to expire on August 31, 2017. In January 2017, the Company signed a lease to extend the use of the same office space from September 1, 2017 to August 31, 2019.

Additionally, on October 21, 2014, the Company leased office space in New York, New York under an operating lease that was originally scheduled to expire on October 31, 2018. In March 2017, the Company commenced a plan to transition its consumer operations from New York to Boston. In connection with this transition, the Company terminated its New York office operating lease and was released from any further obligations in July 2017.

As of December 31, 2017, the minimum future lease payments under the Company’s Boston operating lease was as follows:


2018	$	466,593
2019		311,062

Total minimum lease payments	$	777,655

Rent expense is being recognized on a straight-line basis. The Company recorded approximately $522,000, $337,000 and $253,000 of rent expense for the twelve months ended December 31, 2017, December 31, 2016 and December 31, 2015, respectively.

Royalty agreement

In March 2014, the Company entered into a royalty agreement with certain of its founders. Under the agreement, the Company agreed to pay the founders an aggregate royalty of 2% of gross sales of the Company’s products in perpetuity. The Company began incurring royalty expense upon commencement of HOTSHOT sales during the second quarter of 2016. The Company recorded approximately $25,000 and $20,000 of royalty expense during the twelve months ended December 31, 2017 and December 31, 2016, respectively. Royalty amounts owed to the founders as of December 31, 2017 and December 31, 2016 were approximately $3,000 and $4,000. No royalty amounts were owed to the founders as of December 31, 2015.

Litigation

The Company is not a party to any litigation and does not have contingency reserves established for any litigation liabilities as of December 31, 2017.

Convertible preferred stock	12 Months Ended
Convertible preferred stock	Dec. 31, 2017
Equity [Abstract]
Convertible preferred stock	10. CONVERTIBLE PREFERRED STOCK As of December 31, 2014, the Company had authorized 16,000,000 shares of Series A convertible preferred stock (“Series A Preferred Stock”), $0.0001 par value per share, for issuance. During March, April and May 2014, the Company issued an aggregate of 15,775,221 shares of Series A Preferred Stock for $1.00 per share, resulting in net proceeds to the Company of $15,637,032, which was also the carrying value of the Series A Preferred Stock as of December 31, 2014. As of December 31, 2014, the Company had authorized 14,500,000 shares of Series B convertible preferred stock (“Series B Preferred Stock”), $0.0001 par value per share, for issuance. From July to October 2014, the Company issued an aggregate of 14,078,647 shares of Series B Preferred Stock for $1.81 per share, resulting in net proceeds to the Company of $25,394,135, which was also the carrying value of the Series B Preferred Stock as of December 31, 2014. In conjunction with the Company’s IPO in February 2015, all shares of the Series A and Series B Preferred Stock converted into common stock. As of December 31, 2017, there were no shares of Series A convertible preferred stock or Series B convertible preferred stock authorized. On February 3, 2015, the Company filed an amended and restated certificate of incorporation (the “Restated Certificate”) with the Secretary of State of the State of Delaware in connection with the closing of the Company’s IPO. As of December 31, 2017, under the Restated Certificate, the Company is authorized to issue 10,000,000 shares of preferred stock (“Preferred Stock”) with a par value of $0.0001 per share. The Company has not issued any shares of Preferred Stock as of December 31, 2017.

Common stock

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Federal Home Loan Banks [Abstract]

Common stock

8. COMMON STOCK

As of September 30, 2018, the Company had authorized 100,000,000 shares of common stock, $0.0001 par value per share. Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors. The Company does not intend to declare dividends for the foreseeable future.

Restricted common stock to founders

In March 2014, the Company sold 4,553,415 shares of restricted common stock to the founders of the Company (“recipients”), for $0.0004 per share, for total proceeds of $1,950. In April 2014, based upon anti-dilution provisions granted to the recipients, an additional 867,314 shares of restricted common stock were sold to the same recipients, after which the anti-dilution provisions were terminated. The restricted common stock vested 25% upon issuance, and the remaining 75% vested ratably over four years, during which time the Company had the right to repurchase the unvested shares held by a recipient if the relationship between such recipient and the Company ceased. Such shares were not accounted for as outstanding until they vested. Unvested restricted common stock awards to non-employees were re-measured at each vest date and each financial reporting date. All restricted common stock sold to recipients had vested as of September 30, 2018, and is no longer subject to re-valuation or eligible for repurchase.

The following is a summary of restricted common stock activity:


	Number of Shares			Weighted- Average Grant Date Fair Value
Unvested at December 31, 2017		169,654		$	0.10
Issued		—			—
Vested		(169,654	)		0.10
Forfeited		—			—

Unvested at September 30, 2018		—		$	—

Restricted common stock to consultants

During 2016, the Company issued 18,194 shares of restricted common stock to non-employee consultants and advisors. Such shares are not accounted for as outstanding until they vest. There were 15,485 shares of restricted common stock issued to consultants outstanding as of September 30, 2018. Prior to July 1, 2018, unvested restricted common stock awards to non-employees were re-measured at each vest date and each financial reporting date. On July 1, 2018, the Company adopted ASU No. 2018-07 using a modified retrospective transition approach. As a result, the Company permanently revalued all unvested stock awards granted to non-employees as of July 1, 2018. The adoption-date fair value did not materially change from the fair value as of June 30, 2018 and therefore, a cumulative-effect adjustment was not required.

The following is a summary of restricted common stock activity:


	Number of Shares			Weighted- Average Grant Date Fair Value
Unvested at December 31, 2017		5,334		$	10.51
Issued		—			—
Vested		(2,625	)		9.95
Forfeited		—			—

Unvested at September 30, 2018		2,709		$	11.05

11. COMMON STOCK

As of December 31, 2017, the Company had authorized 100,000,000 shares of common stock, $0.0001 par value per share. Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors. The Company does not intend to declare dividends for the foreseeable future.

Restricted common stock to founders

In March 2014, the Company sold 4,553,415 shares of restricted common stock to the founders of the Company (“recipients”), for $0.0004 per share, for total proceeds of $1,950. In April 2014, based upon anti-dilution provisions granted to the founders, an additional 867,314 shares of restricted common stock were sold to the same founders, after which the anti-dilution provisions were terminated. The restricted common stock vested 25% upon issuance, and the remaining 75% vests ratably over four years, during which time the Company has the right to repurchase the unvested shares held by a recipient if the relationship between such recipient and the Company ceases. If the relationship terminates, the Company has 90 days to repurchase unvested shares at $0.0004. Such shares are not accounted for as outstanding until they vest. There were 5,251,075 shares of restricted common stock outstanding as of December 31, 2017. Unvested restricted common stock awards to non-employees are re-measured at each vest date and each financial reporting date.

The following is a summary of restricted common stock activity:


	Number of Shares			Weighted-Average Grant Date Fair Value
Unvested at December 31, 2016		1,185,958		$	0.10
Issued		—			—
Vested		(1,016,304	)		0.10
Forfeited		—			—

Unvested at December 31, 2017		169,654		$	0.10

The total fair value of shares vested during the twelve months ended 2017, 2016 and 2015 was approximately $3,840,000, $9,646,000 and $15,616,000 respectively.

Restricted common stock to consultants

There were no shares of restricted common stock granted to non-employee consultants and advisors during 2017 or 2015. During 2016, the Company granted a total of 18,194 of shares of restricted common stock to non-employee consultants and advisors. Such shares are not accounted for as outstanding until they vest. There were 12,860 shares of restricted common stock issued to consultants outstanding as of December 31, 2017. Unvested restricted common stock awards to non-employees are re-measured at each vest date and each financial reporting date.

The following is a summary of restricted common stock activity:


	Number of Shares			Weighted-Average Grant Date Fair Value
Unvested at December 31, 2016		10,834		$	9.72
Issued		—			—
Vested		(5,500	)		8.95
Forfeited		—			—

Unvested at December 31, 2017		5,334		$	10.51

The total fair value of shares vested during the twelve months ended 2017 and 2016 was approximately $22,000 and $71,000, respectively. No shares were issued to consultants during the twelve months ended December 31, 2015.

Employee stock purchase plan

In 2015, the Company’s Board of Directors adopted, and the Company’s stockholders approved, the 2015 Employee Stock Purchase Plan (the “ESPP”). As of the December 31, 2017, no shares of common stock have been purchased under the ESPP.

Shares reserved for future issuance

The Company has reserved the following number of shares of common stock for future issuance:


	As of December 31,
	2017		2016
Stock-based compensation awards		3,439,820		2,722,573
Vesting of restricted common stock		174,988		1,196,792
Employee stock purchase plan		534,274		354,569

Total		4,149,082		4,273,934

Stock-based compensation

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-based compensation

9. STOCK-BASED COMPENSATION

In March 2014, the Company adopted the Flex Pharma, Inc. 2014 Equity Incentive Plan (the “2014 Plan”), under which it had the ability to grant incentive stock options (“ISOs”), non-qualified stock options, restricted stock awards, restricted stock units and stock appreciation rights to purchase up to 116,754 shares of common stock. In April 2014, the Company amended the 2014 Plan to reserve for the issuance of up to 1,451,087 shares of common stock pursuant to equity awards. In September 2014, the Company further amended the 2014 Plan to reserve for the issuance of up to 2,070,200 shares of common stock pursuant to equity awards. Terms of stock award agreements, including vesting requirements, were determined by the Board, subject to the provisions of the 2014 Plan. For options granted under the 2014 Plan, the exercise price equaled the fair market value of the common stock as determined by the Board on the date of grant. No further awards will be granted under the 2014 Plan.

In January 2015, the Company’s Board adopted, and the Company’s stockholders approved, the 2015 Equity Incentive Plan (the “2015 Plan”), which became effective immediately prior to the closing of the Company’s initial public offering (“IPO”). The 2015 Plan provides for the grant of ISOs, nonstatutory stock options, restricted stock awards, restricted stock units, stock appreciation rights, performance-based stock awards and other stock-based awards. Additionally, the 2015 Plan provides for the grant of performance-based cash awards. ISOs may be granted only to the Company’s employees. All other awards may be granted to the Company’s employees, including officers, and to non-employee directors and consultants. As of September 30, 2018, there were 1,480,758 shares remaining available for the grant of stock awards under the 2015 Plan.

The Company has awarded stock options to its employees, directors, advisors and consultants, pursuant to the plans described above. Stock options subsequent to the completion of the Company’s IPO are granted with an exercise price equal to the closing market price of the Company’s common stock on the date of grant. Stock options generally vest over one to four years and have a contractual term of ten years. Stock options are valued using the Black-Scholes option pricing model and compensation cost is recognized based on the resulting value over the service period. Prior to July 1, 2018, unvested awards to non-employees were re-measured at each vest date and at each financial reporting date. On July 1, 2018, the Company adopted ASU No. 2018-07 using a modified retrospective transition approach. As a result, the Company permanently revalued all unvested stock options granted to non-employees as of July 1, 2018. The adoption-date fair value did not materially change from the fair value as of June 30, 2018 and therefore, a cumulative-effect adjustment was not required.

The following table summarizes stock option activity for employees and non-employees for the nine months ended September 30, 2018:


	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2017		2,580,491		$	6.65		7.55	$	803,600
Granted		1,517,544			2.74
Exercised		(97,310	)		1.21
Forfeited		(714,699	)		5.96
Expired		(705,387	)		8.35

Outstanding at September 30, 2018		2,580,639		$	4.28		8.07	$	—

Exercisable at September 30, 2018		1,126,248		$	5.92		6.55	$	—

Vested or expected to vest at September 30, 2018		2,580,639		$	4.28		8.07	$	—

Total stock-based compensation expense recognized for employee and non-employee restricted common stock, and stock options granted to employees and non-employees is included in the Company’s condensed consolidated statements of operations as follows:


	Three Months Ended September 30, 2018		Three Months Ended September 30, 2017		Nine Months Ended September 30, 2018		Nine Months Ended September 30, 2017
Research and development	$	43,369	$	386,636	$	674,775	$	1,172,655
Selling, general and administrative		235,021		618,145		1,023,548		2,094,224

Total	$	278,390	$	1,004,781	$	1,698,323	$	3,266,879

As of September 30, 2018, there was approximately $2,481,000 of total unrecognized compensation cost related to unvested equity awards. Total unrecognized compensation cost will be adjusted for future changes in employee and non-employee forfeitures, if any. The Company expects to recognize that cost over a remaining weighted-average period of 2.90 years.

In June 2018, the Company extended the three-month post termination exercisability of 877,137 option awards held by six employees and one adviser to one-year post termination. The Company also extended the three-month post termination exercisability of 500,000 option awards held by one employee to three-years post termination. The valuation of these awards did not change as a result of the modification of these awards and as such, the Company did not recognize any additional compensation expense related to the modification.

On June 14, 2018, the Company granted 654,544 stock options, in the aggregate, to seven employees as part of the Company’s retention arrangements with these employees. These awards vest monthly over 48 months as the employees provide continuous service, and expense is being recognized over this period. The awards are exercisable for one to three-years post termination depending on the employee to which the stock options were granted. The awards vest in full upon a change in control event and termination of the employees under certain circumstances. A change in control event is not currently considered probable for accounting purposes. Unless and until the Company’s Board has approved a specific transaction, the Company’s probability assessment regarding a change in control event is not expected to change.

Employee stock purchase plan

In 2015, the Company’s Board adopted, and the Company’s stockholders approved, the 2015 Employee Stock Purchase Plan (the “ESPP”). As of September 30, 2018, no shares of common stock have been purchased under the ESPP.

12. STOCK-BASED COMPENSATION

In March 2014, the Company adopted the Flex Pharma, Inc. 2014 Equity Incentive Plan (the “2014 Plan”), under which it had the ability to grant incentive stock options (“ISOs”), non-qualified stock options, restricted stock awards, restricted stock units and stock appreciation rights to purchase up to 116,754 shares of common stock. In April 2014, the Company amended the 2014 Plan to reserve for the issuance of up to 1,451,087 shares of common stock pursuant to equity awards. In September 2014, the Company further amended the 2014 Plan to reserve for the issuance of up to 2,070,200 shares of common stock pursuant to equity awards. Terms of stock award agreements, including vesting requirements, were determined by the board of directors, subject to the provisions of the 2014 Plan. For options granted under the 2014 Plan, the exercise price equaled the fair market value of the common stock as determined by the board of directors on the date of grant. No further awards will be granted under the 2014 Plan.

In January 2015, the Company’s board of directors adopted, and the Company’s stockholders approved, the 2015 Equity Incentive Plan (the “2015 Plan”), which became effective immediately prior to the closing of the Company’s IPO. The 2015 Plan provides for the grant of ISOs, nonstatutory stock options, restricted stock awards, restricted stock units, stock appreciation rights, performance-based stock awards and other stock-based awards. Additionally, the 2015 Plan provides for the grant of performance-based cash awards. ISOs may be granted only to the Company’s employees. All other awards may be granted to the Company’s employees, including officers, and to non-employee directors and consultants. As of December 31, 2017, there were 859,329 shares remaining available for the grant of stock awards under the 2015 Plan.

There were no stock options issued to non-employee consultants or members of the Scientific Advisory Board during 2017. During 2016 and 2015, the Company granted a total of 14,670 and 10,507, respectively, of stock options to non-employee consultants and members of its Scientific Advisory Board. The options generally vest over a four-year period, and have a contractual term of ten years. The total stock-based compensation expense related to all non-employee stock options for the year ended December 31, 2017, December 31, 2016 and December 31, 2015 was approximately $201,000, $370,000 and $517,000, respectively.

The Company has awarded stock options to its employees, directors, advisors and consultants, pursuant to the plans described above. Stock options subsequent to the completion of the Company’s IPO are granted with an exercise price equal to the closing market price of the Company’s common stock on the date of grant. Stock options generally vest over one to four years and have a contractual term of ten years. Stock options are valued using the Black-Scholes option pricing model and compensation cost is recognized based on the resulting value over the service period. Unvested awards to non-employees are re-measured at each vest date and at each financial reporting date. The following table summarizes stock option activity for employees and non-employees for the twelve months ended December 31, 2017:


	Shares			Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2016		2,156,250		$	8.66		7.94	$	1,605,684
Granted		1,059,500			4.20
Exercised		(1,576	)		1.67
Forfeited		(418,642	)		8.87
Expired		(215,041	)		10.51

Outstanding at December 31, 2017		2,580,491		$	6.65		7.55	$	803,600

Exercisable at December 31, 2017		1,404,844		$	7.21		6.56	$	692,232

Vested or expected to vest at December 31, 2017		2,580,491		$	6.65		7.55	$	803,600

During 2017, 2016 and 2015, the Company granted stock options to purchase an aggregate of 1,059,500, 763,320, and 994,748 shares of its common stock, respectively. The weighted-average grant date fair value of option awards granted during 2017, 2016 and 2015 were $2.80, $6.35, and $8.55, respectively.

The number of stock options exercised during 2017, 2016 and 2015 were 1,576, 8,516, and 47,280, respectively. The weighted-average exercise price of options exercised during 2017, 2016 and 2015 was $1.67, $2.59, and $8.63, respectively. The total intrinsic value of options exercised during 2017, 2016 and 2015 was $2,606, $64,302, and $149,386, respectively. The intrinsic value is calculated as the difference between the fair value of the Company’s common stock and the exercise price of the options at the date of exercise.

The Company estimates the fair value of each stock option award on the grant date using the Black-Scholes option-pricing model based on the following assumptions regarding the fair value of the underlying Common Stock on each measurement date:

Year Ended
December 31, 2017

Year Ended
December 31, 2016

Year Ended
December 31, 2015

Expected volatility

73.87% to 81.04%

71.01% to 74.20%

72.98% to 74.94%

Risk-free interest rate

1.83% to 2.40%

1.23% to 2.40%

1.62% to 2.49%

Expected term

5.3 - 9.5 years

5.3 - 10 years

Expected dividend yield

Total stock-based compensation expense recognized for employee and non-employee restricted common stock, and stock options granted to employees and non-employees is included in the Company’s consolidated statements of operations and comprehensive loss as follows:


	Year Ended December 31, 2017		Year Ended December 31, 2016		Year Ended December 31, 2015
Research and development	$	1,545,737	$	2,435,565	$	3,192,063
Selling, general and administrative		2,673,428		4,137,398		3,405,296

Total	$	4,219,165	$	6,572,963	$	6,597,359

Selling, general and administrative expense for the year ended December 31, 2016 included $285,000 related to stock options that were modified in connection with an employee termination agreement.

As of December 31, 2017, there was approximately $4,533,000 of total unrecognized compensation cost related to unvested equity awards. Total unrecognized compensation cost will be adjusted for the re-measurement of non-employee awards as well as future changes in employee and non-employee forfeitures, if any. The Company expects to recognize that cost over a remaining weighted-average period of 2.26 years.

Income taxes

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income taxes

10. INCOME TAXES

Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax basis of assets and liabilities using statutory rates. A valuation allowance is recorded against deferred tax assets if it is more likely than not that some or all of the deferred tax assets will not be realized. Based upon the Company’s history of operating losses and the uncertainty surrounding the realization of the favorable tax attributes in future tax returns, the Company has recorded a full valuation allowance against the Company’s otherwise recognizable net deferred tax assets. There was no significant income tax provision or benefit for the nine months ended September 30, 2018 or 2017.

In March 2018, the FASB issued ASU No. 2018-05, Income Taxes (Topic 740), Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118. The ASU adds various Securities and Exchange Commission (“SEC”) paragraphs pursuant to the issuance of the December 2017 SEC Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB 118), which was effective immediately. The SEC issued SAB 118 to address concerns about a reporting entity’s ability to timely comply with the accounting requirements to recognize all of the effects of the Tax Cuts and Jobs Act in the period of enactment. SAB 118 allows disclosure that timely determination of some or all of the income tax effects from the Tax Cuts and Jobs Act are incomplete by the due date of the financial statements and, if possible, to provide a reasonable estimate. The Company’s accounting for certain income tax effects is incomplete, but it has determined reasonable estimates for those effects and has included provisional amounts in its condensed consolidated financial statements as of September 30, 2018 and December 31, 2017.

13. INCOME TAXES

For the years ended December 31, 2017, December 31, 2016 and December 31, 2015, the Company did not record a current or deferred income tax provision or benefit. The Company’s losses before income taxes for the periods presented consisted solely of domestic losses.

On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act tax reform legislation. This legislation makes significant changes in U.S. tax law including a reduction in the corporate tax rates, changes to net operating loss carryforwards and carrybacks, and a repeal of the corporate alternative minimum tax. The legislation reduced the U.S. corporate tax rate from the current rate of 35% to 21%. As a result of the enacted law, the Company was required to revalue deferred tax assets and liabilities at the enacted rate. This revaluation resulted in a decrease in net deferred tax assets of $12,600,000 and a corresponding reduction in the valuation allowance against these assets. There is no impact to income tax expense. The other provisions of the Tax Cuts and Jobs Act did not have a material impact on the 2017 consolidated financial statements.

On December 22, 2017, the SEC staff issued Staff Accounting Bulletin No. 118, or SAB 118, to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed, including computations, in reasonable detail to complete the accounting for certain income tax effects of the Tax Reform Act. The Company has recognized the provisional tax impacts related to the revaluation of the deferred tax assets and liabilities and included these amounts in its consolidated financial statements for the year ended December 31, 2017. The ultimate impact may differ from these provisional amounts due to, among other things, additional analysis, changes in interpretations and assumptions the Company has made, additional regulatory guidance that may be issued, and actions the Company may take as a result of the Tax Reform Act. The accounting is expected to be complete when the 2017 U.S. corporate income tax return is filed in 2018.

The following table presents a reconciliation of income tax expense (benefit) computed at the statutory federal income tax rate to the effective income tax rate as reflected in the consolidated financial statements:


	Year Ended December 31, 2017			Year Ended December 31, 2016			Year Ended December 31, 2015
Federal income tax expense at statutory rate		35.0	%		35.0	%		35.0	%
State income tax, net of federal benefit		5.0	%		5.0	%		3.4	%
Permanent differences		(0.7	)%		0.0	%		(0.2	)%
Stock-based compensation		(1.9	)%		(2.6	)%		(6.3	)%
Research credits		2.2	%		1.9	%		1.8	%
Other, net		(1.3	)%		(0.1	)%		0.4	%
Payroll Tax Credit Election		(0.7	)%		0.0	%		0.0	%
Change in valuation allowance		(1.1	)%		(39.2	)%		(34.1	)%
Deferred rate change		(36.5	)%		0.0	%		0.0	%

Effective tax rate		0.0	%		0.0	%		0.0	%

Deferred income tax assets and liabilities are determined based upon temporary differences between the financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse.

The following table presents the significant components of the Company’s deferred tax assets and liabilities:


	December 31, 2017			December 31, 2016
Deferred tax assets:
U.S. and state net operating loss carryforwards	$	24,744,841		$	24,322,172
Accruals and other temporary differences		202,301			529,462
Amortization		35,783			32,171
Stock-based compensation		1,591,131			1,847,441
Tax credit carryforward		1,964,189			1,423,292

Total deferred tax assets		28,538,245			28,154,538
Less valuation allowance		(28,533,755	)		(28,127,611	)

Deferred tax assets		4,490			26,927

Deferred tax liabilities:
Stock-based compensation		(4,490	)		(23,316	)
Depreciation		—			(3,611	)
Accruals and other temporary differences		—			—

Deferred tax liabilities		(4,490	)		(26,927	)

Net deferred tax assets	$	—		$	—

As of December 31, 2017, the Company has U.S. federal net operating loss carryforwards of approximately $91,200,000 and U.S. state net operating loss carryforwards of approximately $90,400,000 ($7,100,000 tax affected), which are available to reduce future taxable income. The Company also had federal research and development tax credit carryforwards of approximately $1,600,000 and state research and development tax credit carryforwards of approximately $428,000, which may be used to offset future tax liabilities.

The Company adopted ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting, for the quarter ended March 31, 2017. As a result of adoption, the deferred tax assets associated net operating losses increased by approximately $42,000. These amounts were offset by a corresponding increase in the valuation allowance. The adoption of ASU 2016-09 had no impact to the Company’s consolidated statement of operations, balance sheet, or retained earnings.

The Company’s federal and state operating loss carryforwards and tax credit carryforwards will expire at various dates through 2037. Under the provisions of the Internal Revenue Code, the net operating loss and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service and state tax authorities. Net operating loss and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant shareholders over a three-year period in excess of 50 percent, as defined under Sections 382 and 383 of the Internal Revenue Code, respectively, as well as similar state provisions. This could limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the value of the Company immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation in future years. The Company has completed financings since its inception which may have resulted in a change in control as defined by Sections 382 and 383 of the Internal Revenue Code, or could result in a change in control in the future. The Company has not conducted an assessment to determine whether there may have been a Section 382 or 383 ownership changes.

ASC 740 requires a valuation allowance to reduce the deferred tax assets reported if, based on the weight of available evidence, it is more likely than not that some portion or all of the deferred tax assets will not be realized. After considerations of all the evidence, both positive and negative, the Company continues to maintain a valuation allowance for the full amount of the 2017 deferred tax asset because it is more likely than not that the deferred tax asset will not be realized. The valuation allowance increased by approximately $406,000 from December 31, 2016 to December 31, 2017, primarily due to an increase in net operating losses.

The Company has no unrecognized tax benefits. Interest and penalty charges, if any, related to uncertain tax positions would be classified as income tax expenses in the accompanying consolidated statement of operations. At December 31, 2017 and 2016, the Company had no accrued interest or penalties related to uncertain tax positions.

Under the Protecting Americans from Tax Hikes Act, enacted in December 2015, certain qualified small businesses may elect to apply up to $250,000 of its federal research and development tax credit against the Social Security portion of its payroll tax liability. The Company elected the $250,000 credit on its 2016 tax return and utilized approximately $22,000 of the credit as a decrease to its payroll tax expense in 2017.

Net loss per share

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Earnings Per Share [Abstract]

Net loss per share

11. NET LOSS PER SHARE

As the Company has reported a net loss for the periods presented, diluted net loss per common share is the same as basic net loss per common share.

The following potentially dilutive securities outstanding, prior to the use of the treasury stock method or if-converted method, have been excluded from the computation of diluted weighted-average shares outstanding for the periods indicated, because including them would have had an anti-dilutive impact:


	September 30, 2018		September 30, 2017
Options to purchase common stock		2,580,639		2,701,922
Unvested restricted common stock		2,709		430,439

Total		2,583,348		3,132,361

14. NET LOSS PER SHARE

Because the Company has reported net losses for the periods presented, diluted net loss per common share is the same as basic net loss per common share.


	Year Ended December 31, 2017		Year Ended December 31, 2016		Year Ended December 31, 2015
Options to purchase common stock		2,580,491		2,156,250		1,824,973
Unvested restricted common stock		174,988		1,196,792		2,202,262

Total		2,755,479		3,353,042		4,027,235

SEGMENT INFORMATION

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Segment Reporting [Abstract]

Segment Information

12. SEGMENT INFORMATION

The Company operates as two reportable segments:

•

The Consumer Operations segment, which reflects the total revenue and costs and expenses related to HOTSHOT and the Company’s consumer operations.

•

The Drug Development segment, which reflects the costs and expenses related to the Company’s efforts to develop innovative and proprietary drug products; previously to treat muscle cramps, spasms and spasticity associated with severe neurological conditions.

The Company discloses information about its reportable segments based on the way that the Company’s Chief Operating Decision Maker, who the Company has identified as the Chief Executive Officer, and management, organize segments within the Company for making operating decisions and assessing financial performance. The Company evaluates the performance of its reportable segments based on revenue and operating income or loss. The accounting policies of the segments are the same as those described herein as well as those described in Note 2 to the audited consolidated financial statements in the 2017 Form 10-K. Corporate and unallocated amounts that do not relate to a reportable segment have been allocated to “Corporate”. No asset information has been provided for the Company’s reportable segments as management does not measure or allocate such assets on a reportable segment basis.

Information for the Company’s reportable segments for the three months ended September 30, 2018 and 2017 are as follows:


Three Months Ended September 30, 2018	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	250,991		—		—	$	250,991
Interest income, net	$	—		—		28,210	$	28,210
Loss from operations	$	18,293		864,934		1,783,356	$	2,666,583

Three Months Ended September 30, 2017	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	413,601		—		—	$	413,601
Interest income, net	$	—		—		77,339	$	77,339
Loss from operations	$	2,323,919		4,683,533		2,402,000	$	9,409,452

Information for the Company’s reportable segments for the nine months ended September 30, 2018 and 2017 are as follows:


Nine Months Ended September 30, 2018	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	675,075		—		—	$	675,075
Interest income, net	$	—		—		139,612	$	139,612
Loss from operations	$	1,921,286		11,699,499		6,432,299	$	20,053,084

Nine Months Ended September 30, 2017	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	991,671		—		—	$	991,671
Interest income, net	$	—		—		227,535	$	227,535
Loss from operations	$	7,072,225		12,472,149		7,088,292	$	26,632,666

15. SEGMENT INFORMATION

Effective as of the second quarter of 2016 and in connection with the launch of HOTSHOT, the Company operates as two reportable segments:

•

The Consumer Operations segment, which reflects the total revenue and costs and expenses related to HOTSHOT and the Company’s consumer operations.

•

The Drug Development segment, which reflects the costs and expenses related to the Company’s efforts to develop innovative and proprietary drug products to treat muscle cramps, spasms and spasticity associated with severe neurological conditions.

The Company discloses information about its reportable segments based on the way that the Company’s Chief Operating Decision Maker, who the Company has identified as the Chief Executive Officer, and management, organizes segments within the Company for making operating decisions and assessing financial performance. The Company evaluates the performance of its reportable segments based on revenue and operating income or loss. The accounting policies of the segments are the same as those described herein as well as those described in Note 2. Corporate and unallocated amounts that do not relate to a reportable segment have been allocated to “Corporate”. No asset information has been provided for the Company’s reportable segments as management does not measure or allocate such assets on a reportable segment basis.

Information for the Company’s reportable segments for the years ended December 31, 2017, December 31, 2016, and December 31, 2015 are as follows:


Year Ended December 31, 2017	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	1,274,499		—		—	$	1,274,499
Loss from operations	$	8,877,330		16,715,752		9,132,544	$	34,725,626
Interest income, net	$	—		—		291,964	$	291,964


Year Ended December 31, 2016	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	1,010,663		—		—	$	1,010,663
Loss from operations	$	10,023,137		19,620,338		10,242,757	$	39,886,232
Interest income, net	$	—		—		393,109	$	393,109


Year Ended December 31, 2015	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	—		—		—	$	—
Loss from operations	$	7,892,584		12,224,692		9,096,382	$	29,213,658
Interest income, net	$	—		—		72,028	$	72,028

Related parties	12 Months Ended
Related parties	Dec. 31, 2017
Related Party Transactions [Abstract]
Related parties	16. RELATED PARTIES *Royalty agreement* In 2014, the Company entered into a royalty agreement with certain of the Company’s founders under which these founders are paid a royalty of 2%, in the aggregate, of gross sales of any product sold by the Company or by any of the Company’s licensees for use in the treatment of any neuromuscular disorder, and that uses, incorporates or embodies, or is made using, any of the Company’s intellectual property, including any know-how. Upon the launch of HOTSHOT in the second quarter of 2016, the Company’s founders began earning royalties under this agreement. Royalty amounts earned by the founders during the years ended December 31, 2017 and December 31, 2016 totaled approximately $25,000 and $20,000, respectively, including approximately $3,000 and $4,000 not yet paid as of year end, respectively. There were no such amounts earned during the year ended December 31, 2015. Royalty expense is recorded in cost of product revenue in the consolidated statement of operations. *License agreement* For the period from May 2014 through July 2016, the Company licensed a portion of its office space to ECLDS, LLC, which was controlled by the Company’s former Chief Executive Officer. In October 2015, the license agreement was assigned by ECLDS, LLC to a third party, that was not owned by the Company’s former Chief Executive Officer, but for which a business relationship existed. In July 2016, the license agreement terminated. Under the terms of the license, the entity charged the same rental rate as that was charged to the Company. During the years ended December 31, 2016 and December 31, 2015, the Company received approximately $32,000, and $61,000, respectively, in license fees from the aforementioned related party, and such amounts received have been recorded as a reduction to rent expense.

Quarterly financial information (unaudited)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Quarterly financial information (unaudited)

17. QUARTERLY FINANCIAL INFORMATION (UNAUDITED)


	First Quarter Ended March 31, 2017			Second Quarter Ended June 30, 2017			Third Quarter Ended September 30, 2017			Fourth Quarter Ended December 31, 2017
Net product revenue	$	240,292		$	330,688		$	407,241		$	282,752
Other revenue		2,255			4,835			6,360			76

Total revenue		242,547			335,523			413,601			282,828
Costs and expenses:
Cost of product revenue		79,106			145,325			148,756			133,343
Research and development		3,914,974			4,076,220			4,739,360			4,259,357
Selling, general and administrative		4,594,716			4,990,943			4,934,937			3,983,088

Total costs and expenses		8,588,796			9,212,488			9,823,053			8,375,788

Loss from operations		(8,346,249	)		(8,876,965	)		(9,409,452	)		(8,092,960	)
Interest income, net		77,854			72,342			77,339			64,429

Net loss	$	(8,268,395	)	$	(8,804,623	)	$	(9,332,113	)	$	(8,028,531	)

Net loss per share attributable to common stockholders – basic and diluted	$	(0.49	)	$	(0.51	)	$	(0.54	)	$	(0.46	)

Weighted-average number of common shares outstanding – basic and diluted		16,873,512			17,130,264			17,386,249			17,642,646


	First Quarter Ended March 31, 2016			Second Quarter Ended June 30, 2016			Third Quarter Ended September 30, 2016			Fourth Quarter Ended December 31, 2016
Net product revenue	$	—		$	112,685		$	586,134		$	291,099
Other revenue		—			—			12,940			7,805

Total revenue		—			112,685			599,074			298,904

Costs and expenses:
Cost of product revenue		197,020			110,931			221,090			133,706
Research and development		4,387,079			6,094,921			5,665,357			4,230,804
Selling, general and administrative		5,111,695			5,377,784			5,447,847			3,918,661

Total costs and expenses		9,695,794			11,583,636			11,334,294			8,283,171

Loss from operations		(9,695,794	)		(11,470,951	)		(10,735,220	)		(7,984,267	)
Interest income, net		103,333			107,818			97,726			84,232

Net loss	$	(9,592,461	)	$	(11,363,133	)	$	(10,637,494	)	$	(7,900,035	)

Net loss per share attributable to common stockholders – basic and diluted	$	(0.61	)	$	(0.71	)	$	(0.65	)	$	(0.48	)

Weighted-average number of common shares outstanding – basic and diluted		15,843,532			16,105,555			16,361,617			16,619,596

Subsequent events	12 Months Ended
Subsequent events	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent events	18. SUBSEQUENT EVENTS The Company has completed an evaluation of all subsequent events after the balance sheet date of December 31, 2017 through the date these consolidated financial statements were issued. The Company concluded that no subsequent events have occurred that require disclosure.

Revenue from contracts with customers	9 Months Ended
Revenue from contracts with customers	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue from contracts with customers	3. REVENUE FROM CONTRACTS WITH CUSTOMERS *Adoption of ASC Topic 606, “Revenue from Contracts with Customers”* On January 1, 2018, the Company adopted ASC 606 using the modified retrospective method applied to contracts not yet completed as of January 1, 2018. Results for reporting periods beginning after January 1, 2018 are presented under ASC 606, while prior period amounts are not adjusted and are reported in accordance with the Company’s historical accounting under ASC 605. The primary impact of the adoption of ASC 606 related to the timing of revenue recognized for e-commerce sales, due to e-commerce refund rights. Under ASC 606, the Company recognizes revenue when control of the promised good is transferred to the customer, and reflects the consideration to which the Company expects to be entitled to receive in exchange for the good. This has resulted in accelerated revenue recognition for e-commerce sales, as under ASC 605, all revenue and related costs were deferred and recognized once the refund period lapsed. The cumulative effect of applying the new guidance to all contracts that were not completed as of January 1, 2018 was recorded as an adjustment to accumulated deficit of approximately $40,000 as of the adoption date, which was primarily the result of reducing deferred revenue by approximately $70,000 and deferred cost of product revenue and selling fees by approximately $30,000, that were recorded on the consolidated balance sheet at December 31, 2017. The Company would have recognized approximately $1,000 and $29,000 of additional total revenue during the three and nine months ended September 30, 2018, respectively, if the Company had continued to recognize revenue under ASC 605. The adoption of ASC 606 did not impact income taxes, as the Company fully reserves its net deferred tax assets. Therefore, the change to the Company’s net deferred tax asset position due to adoption was offset by a corresponding change to the valuation allowance. *Revenue recognition* Revenue includes sales of HOTSHOT bottled finished goods to e-commerce customers, specialty retailers and sports teams, including professional and collegiate teams. Revenue also consists of payments made by customers for expedited shipping and handling. The Company expenses fulfillment costs as incurred because the amortization period would be less than one year in accordance with the ASC 606 practical expedient. In accordance with ASC 606, the Company applies the following steps to recognize revenue for the sale of bottled finished goods that reflects the consideration to which the Company expects to be entitled to receive in exchange for the promised goods: Identify the contract with a customer A contract with a customer exists when the Company enters into an enforceable contract with a customer. The contract is based on either the acceptance of standard terms and conditions on the websites for e-commerce customers, or the execution of terms and conditions contracts with specialty retailers and sports teams. These contracts define each party’s rights, payment terms and other contractual terms and conditions of the sale. The Company applies judgment in determining the customer’s ability and intention to pay, which is based on a variety of factors including the customer’s historical payment experience and, in some circumstances, published credit and financial information pertaining to the customer. Identify the performance obligations in the contract Performance obligations promised in a contract are identified based on the goods that will be transferred to the customer that are both capable of being distinct and are distinct in the context of the contract, whereby the transfer of the goods is separately identifiable from other promises in the contract. The Company has concluded the sale of bottled finished goods and related shipping and handling are accounted for as a single performance obligation. Determine the transaction price The transaction price is determined based on the consideration to which the Company will be entitled to receive in exchange for transferring goods to the customer. For sales through June 18, 2018, the Company offered refunds to e-commerce customers, upon request, within 30 days of delivery. For sales subsequent to June 18, 2018, the Company now offers refunds to e-commerce customers, upon request, within 14 days of delivery. The Company estimates the amount of potential refunds at each reporting period using a portfolio approach of historical data, adjusted for changes in expected customer experience, including seasonality and changes in economic factors, as necessary. For specialty retailers and sports teams, the Company does not offer a right of return or refund and revenue is recognized at the time products are delivered to customers. Discounts provided to customers are accounted for as an element of the transaction price and as a reduction to revenue, and were approximately $2,000 and $19,000 for the three and nine months ended September 30, 2018, respectively, and approximately $82,000 and $202,000 for the three and nine months ended September 30, 2017, respectively. Revenue is presented net of taxes collected from customers and remitted to governmental authorities. Determine the satisfaction of performance obligation Revenue is recognized when control of the bottled finished goods is transferred to the customer. Control of the bottled finished goods is transferred at a point in time, upon delivery to the customer. The period of time between the satisfaction of the performance obligation and when payment is due from the customer is not significant. *Concentrations of credit risk* The Company had no customers that represented greater than 10% of total revenue during the three and nine months ended September 30, 2018 or the three and nine months ended September 30, 2017. The vast majority of revenue was generated from sales within the United States.

Summary of significant accounting policies (Policies)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Accounting Policies [Abstract]

Basis of presentation

Basis of presentation and use of estimates

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company’s management evaluates its estimates, which include, but are not limited to, estimates related to clinical study accruals, estimates related to inventory realizability, stock-based compensation expense and amounts of expenses during the reported period. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions.

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company’s management evaluates its estimates, which include, but are not limited to, estimates related to inventory write-offs, clinical study accruals, stock-based compensation expense, and amounts of expenses during the reported period. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions.

Principles of consolidation

Principles of consolidation

Concentrations of risk, Concentrations of credit risk and off-balance sheet risk

Concentrations of credit risk and off-balance sheet risk

Concentration of risk

Segment information

Segment information

Revenue

Net product revenue and other revenue are presented net of taxes collected from customers and remitted to governmental authorities.

Revenue

Revenue is comprised of net product revenue and other revenue. Net product revenue includes sales of HOTSHOT finished goods to e-commerce customers, specialty retailers and sports teams. Other revenue consists of payments made by customers for expedited shipping and handling, which the Company began offering during the third quarter of 2016. Revenue is recognized when persuasive evidence of an arrangement exists, delivery of the product has occurred, the sales price is fixed or determinable and collectibility is reasonably assured. For sales through September 30, 2016, the Company issued refunds to e-commerce customers, upon request, within 21 days of shipment. When the Company began selling HOTSHOT on a third-party e-commerce website in October 2016, the refund period and related deferral period increased, as the Company began offering refunds to e-commerce customers, upon request, within 30 days of delivery, for purchases subsequent to September 30, 2016. As the Company currently does not have adequate history to accurately estimate refunds, all e-commerce sales, and their related costs, are deferred and revenue is recognized once the refund period lapses. This deferral represents total deferred revenue presented on the Company's consolidated balance sheet. For specialty retailers and sports teams, the Company does not offer a right of return or refund and revenue is recognized at the time products are delivered to customers.

Revenue, discounts

Accounts receivable and allowance for doubtful accounts

Receivables are evaluated for collection probability on a regular basis and an allowance for doubtful accounts is recorded, if necessary.

Accounts receivable and allowance for doubtful accounts

Accounts receivable are stated at their carrying values, net of any allowances for doubtful accounts. Accounts receivable consist primarily of amounts due from specialty retailers and sports teams, for which collectability is reasonably assured. Receivables are evaluated for collectability on a regular basis and an allowance for doubtful accounts is recorded, if necessary.

Cost of product revenue

Cost of product revenue

Inventory

Inventory

The Company outsources the manufacture of HOTSHOT to a co-packer. Inventory at December 31, 2017 includes raw materials available for future production runs, as well as finished goods.

Advertising expense

Advertising expense

Advertising expense consists of media and production costs related to print and digital advertising. All advertising is expensed as incurred.

Advertising expense

Advertising expense consists of media and production costs related to print and digital advertising. All advertising is expensed as incurred.

Shipping and handling costs

Shipping and handling costs

Shipping and handling costs related to the movement of inventory to the Company’s co-packer and from the co-packer to the Company’s third-party warehousing and fulfillment partners is capitalized as inventory and expensed as a cost of product revenue when revenue is recognized. Shipping and handling costs to move finished goods from the Company’s warehousing and third-party fulfillment partners to customer locations are included in selling, general and administrative expense in the consolidated statement of operations

Property and equipment

Property and equipment


Asset type		Estimated useful life
Computers and computer equipment		3 years
Laboratory equipment		3 years
Manufacturing equipment		3 years
Website development costs		1-2 years

Impairment of long-lived assets

Impairment of long-lived assets

Research and development expense

Research and development expense

Stock-based compensation expense

Stock-based compensation expense

Income taxes

Income taxes

Net loss per share attributable to common stockholders

Net loss per share attributable to common stockholders

Comprehensive loss

Comprehensive loss

Recent accounting pronouncements

Recent accounting pronouncements


	September 30, 2018		December 31, 2017
Cash and cash equivalents	$	12,961,126	$	19,186,036
Restricted cash		126,595		126,595

Cash, cash equivalents and restricted cash shown on the condensed consolidated statement of cash flows	$	13,087,721	$	19,312,631

Recent accounting pronouncements

In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The update amends the guidance in ASU 230 Statement of Cash Flows, and clarifies how entities should classify certain cash receipts and cash payments on the statement of cash flows with the objective of reducing the existing diversity in practice related to eight specific cash flow issues. The amendments in this update are effective for fiscal years beginning after December 15, 2017, and interim periods within those years. Early adoption is permitted. The Company does not expect the adoption of ASU 2016-15 to have a material impact on its consolidated financial statements.

In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows, which amends ASU Topic 230. This update requires entities to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. As a result, entities will no longer be required to present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. When cash, cash equivalents, restricted cash and restricted cash equivalents are presented in more than one line item on the balance sheet, the new guidance requires a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheet. Entities will also have to disclose the nature of their restricted cash and restricted cash equivalent balances. The guidance is effective for fiscal years beginning after December 15, 2017 and interim periods within those years. Early adoption is permitted. Entities are required to apply the guidance retrospectively. The new guidance will change the presentation of restricted cash in the Company’s consolidated financial statements in the first quarter of 2018.

Subsequent events

Subsequent events

Fair value measurements

Level 1 – Unadjusted quoted prices in active markets for identical assets or liabilities.

Marketable securities

Management determines the appropriate classification of the securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. The Company classifies its marketable securities as available-for-sale pursuant to ASC 320, Investments – Debt and Equity Securities. Marketable securities are recorded at fair value, with unrealized gains and losses included as a component of accumulated other comprehensive income (loss) in stockholders’ equity and a component of total comprehensive income (loss) in the consolidated statement of comprehensive income (loss), until realized. Realized gains and losses are included in investment income on a specific-identification basis. There were no realized gains on marketable securities during the year ended December 31, 2017, and there were immaterial realized gains on marketable securities during the year ended December 31, 2016.

Accounts receivable

Accounts receivable and allowance for doubtful accounts

Restricted cash

Restricted cash

The Company has restricted cash in the form of a letter of credit it maintains as a security deposit on the lease of its office space in Boston, Massachusetts.

Restructuring-related costs

Restructuring-related costs

Summary of significant accounting policies (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Accounting Policies [Abstract]

Reclassification out of Accumulated Other Comprehensive Income

The following tables summarize the changes in accumulated other comprehensive loss during the years ended December 31, 2017, December 31, 2016 and December 31, 2015.


Balance as of December 31, 2016	$	(1,614	)
Other comprehensive gain		367

Balance as of December 31, 2017	$	(1,247	)


Balance as of December 31, 2015	$	(24,654	)
Other comprehensive gain		23,040

Balance as of December 31, 2016	$	(1,614	)


Balance as of December 31, 2014	$	—
Other comprehensive loss		(24,654	)

Balance as of December 31, 2015	$	(24,654	)

Schedule Of Cash And Cash Equivalents


	September 30, 2018		December 31, 2017
Cash and cash equivalents	$	12,961,126	$	19,186,036
Restricted cash		126,595		126,595

Cash, cash equivalents and restricted cash shown on the condensed consolidated statement of cash flows	$	13,087,721	$	19,312,631

Fair value measurements (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Summary of Cash Equivalents and Marketable Securities Measured at Fair Value on a Recurring Basis

The following tables summarize the cash equivalents and marketable securities measured at fair value on a recurring basis as of September 30, 2018 and December 31, 2017:


	Level 1		Level 2		Level 3		Balance as of September 30, 2018
Cash equivalents	$	2,321,614	$	—	$	—	$	2,321,614

	$	2,321,614	$	—	$	—	$	2,321,614


	Level 1		Level 2		Level 3		Balance as of December 31, 2017
Cash equivalents	$	5,046,205	$	—	$	—	$	5,046,205
Marketable securities:
U.S. government agency securities		—		8,986,259		—		8,986,259
Commercial paper		—		4,440,689		—		4,440,689
Corporate debt securities		—		702,775		—		702,775

	$	5,046,205	$	14,129,723	$	—	$	19,175,928

The following table summarizes the cash equivalents and marketable securities measured at fair value on a recurring basis as of December 31, 2017 and December 31, 2016:


	Level 1		Level 2		Level 3		Balance at December 31, 2017
Cash equivalents	$	5,046,205	$	—	$	—	$	5,046,205
Marketable securities:
U.S. government agency securities		—		8,986,259		—		8,986,259
Commercial paper		—		4,440,689		—		4,440,689
Corporate debt securities		—		702,775		—		702,775

	$	5,046,205	$	14,129,723	$	—	$	19,175,928


	Level 1		Level 2		Level 3		Balance at December 31, 2016
Cash equivalents	$	11,681,074	$	—	$	—	$	11,681,074
Marketable securities:
U.S. government agency securities		—		31,059,491		—		31,059,491
Commercial paper		—		6,081,202		—		6,081,202
Corporate debt securities		—		1,518,240		—		1,518,240

	$	11,681,074	$	38,658,933	$	—	$	50,340,007

Cash equivalents and marketable securities (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Cash and Cash Equivalents [Abstract]

Schedule of Marketable Securities

Marketable securities at December 31, 2017 and December 31, 2016 consisted of the following:


	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
As of December 31, 2017
Current (due within 1 year):
U.S. government agency securities	$	8,987,254	$	38	$	(1,033	)	$	8,986,259
Commercial paper		4,440,689		—		—			4,440,689
Corporate debt securities		703,027		—		(252	)		702,775

Total	$	14,130,970	$	38	$	(1,285	)	$	14,129,723


	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
As of December 31, 2016
Current (due within 1 year):
U.S. government agency securities	$	31,060,710	$	2,912	$	(4,131	)	$	31,059,491
Commercial paper		6,081,202		—		—			6,081,202
Corporate debt securities		1,518,635		—		(395	)		1,518,240

Total	$	38,660,547	$	2,912	$	(4,526	)	$	38,658,933

Schedule Of Marketable Securities

The Company held no marketable securities at September 30, 2018. Marketable securities at December 31, 2017 consisted of the following:


	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
As of December 31, 2017
Current (due within 1 year):
U.S. government agency securities	$	8,987,254	$	38	$	(1,033	)	$	8,986,259
Commercial paper		4,440,689		—		—			4,440,689
Corporate debt securities		703,027		—		(252	)		702,775

Total	$	14,130,970	$	38	$	(1,285	)	$	14,129,723

Inventory (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Inventory Disclosure [Abstract]

Schedule Of Inventory, Net

The following table presents inventory:


	September 30, 2018		December 31, 2017
Raw materials	$	7,240	$	17,411
Finished goods		216,279		414,480

Total inventory	$	223,519	$	431,891

The following table presents inventory:


	December 31, 2017		December 31, 2016
Raw materials	$	17,411	$	19,888
Finished goods		414,480		434,244

Total inventory	$	431,891	$	454,132

Property and equipment, net (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property and equipment, net

Depreciation is recorded, once assets are placed in service, using the straight-line method over the estimated useful lives of the respective assets, which are as follows:


Asset type		Estimated useful life
Computers and computer equipment		3 years
Laboratory equipment		3 years
Manufacturing equipment		3 years
Website development costs		1-2 years

Property and equipment, net consists of the following:


	December 31, 2017			December 31, 2016
Manufacturing equipment	$	421,999		$	421,999
Computers and computer equipment		311,847			276,263
Website development costs		177,886			159,836
Laboratory equipment		13,368			13,368
Capital in progress		28,823			7,863

Total property and equipment		953,923			879,329
Accumulated depreciation		(622,883	)		(323,014	)

Property and equipment, net	$	331,040		$	556,315

Accrued expenses and other current liabilities (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Payables and Accruals [Abstract]

Schedule Of Accrued Expenses

Accrued expenses and other current liabilities consisted of the following:


	September 30, 2018		December 31, 2017
Phase 2 MND and CMT clinical trial-related costs	$	609,222	$	1,850,115
Payroll and other employee-related costs		430,560		874,246
Professional fees		284,725		227,980
Restructuring-related costs		189,927		—
Other research and development-related costs		23,808		652,285
Consumer product-related costs		16,437		107,595

Total	$	1,554,679	$	3,712,221

Accrued expenses and other current liabilities consist of the following:


	December 31, 2017		December 31, 2016
Research and development costs	$	2,502,400	$	938,665
Payroll and employee-related costs		874,246		1,453,665
Professional fees		227,980		153,219
Consumer product-related costs		107,595		42,024

Total	$	3,712,221	$	2,587,573

Schedule Of Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following:


	September 30, 2018		December 31, 2017
Phase 2 MND and CMT clinical trial-related costs	$	609,222	$	1,850,115
Payroll and other employee-related costs		430,560		874,246
Professional fees		284,725		227,980
Restructuring-related costs		189,927		—
Other research and development-related costs		23,808		652,285
Consumer product-related costs		16,437		107,595

Total	$	1,554,679	$	3,712,221

Restructuring And Related Costs

The following table outlines the Company’s restructuring activities for the nine months ended September 30, 2018:


Opening balance	$	—
Charges:
Employee termination benefits		950,637
Employee retention benefits		164,813
Other		14,995
Payments		(940,518	)

Accrued restructuring balance as of September 30, 2018	$	189,927

Commitments and contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Minimum future lease payments

As of December 31, 2017, the minimum future lease payments under the Company’s Boston operating lease was as follows:


2018	$	466,593
2019		311,062

Total minimum lease payments	$	777,655

Common stock (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Federal Home Loan Banks [Abstract]

Restricted Common Stock Activity

The following is a summary of restricted common stock activity:


	Number of Shares			Weighted- Average Grant Date Fair Value
Unvested at December 31, 2017		169,654		$	0.10
Issued		—			—
Vested		(169,654	)		0.10
Forfeited		—			—

Unvested at September 30, 2018		—		$	—

The following is a summary of restricted common stock activity:


	Number of Shares			Weighted- Average Grant Date Fair Value
Unvested at December 31, 2017		5,334		$	10.51
Issued		—			—
Vested		(2,625	)		9.95
Forfeited		—			—

Unvested at September 30, 2018		2,709		$	11.05

The following is a summary of restricted common stock activity:


	Number of Shares			Weighted-Average Grant Date Fair Value
Unvested at December 31, 2016		1,185,958		$	0.10
Issued		—			—
Vested		(1,016,304	)		0.10
Forfeited		—			—

Unvested at December 31, 2017		169,654		$	0.10

The following is a summary of restricted common stock activity:


	Number of Shares			Weighted-Average Grant Date Fair Value
Unvested at December 31, 2016		10,834		$	9.72
Issued		—			—
Vested		(5,500	)		8.95
Forfeited		—			—

Unvested at December 31, 2017		5,334		$	10.51

Shares reserved for future issuance

The Company has reserved the following number of shares of common stock for future issuance:


	As of December 31,
	2017		2016
Stock-based compensation awards		3,439,820		2,722,573
Vesting of restricted common stock		174,988		1,196,792
Employee stock purchase plan		534,274		354,569

Total		4,149,082		4,273,934

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65888546&loc=d3e21300-112643

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21553-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=65877616&loc=d3e177068-122764

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21538-112644

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(d))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21488-112644

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 11: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(27))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 13: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21484-112644

Reference 14: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

Stock-based compensation (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of stock option activity

The following table summarizes stock option activity for employees and non-employees for the nine months ended September 30, 2018:


	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2017		2,580,491		$	6.65		7.55	$	803,600
Granted		1,517,544			2.74
Exercised		(97,310	)		1.21
Forfeited		(714,699	)		5.96
Expired		(705,387	)		8.35

Outstanding at September 30, 2018		2,580,639		$	4.28		8.07	$	—

Exercisable at September 30, 2018		1,126,248		$	5.92		6.55	$	—

Vested or expected to vest at September 30, 2018		2,580,639		$	4.28		8.07	$	—

The following table summarizes stock option activity for employees and non-employees for the twelve months ended December 31, 2017:


	Shares			Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2016		2,156,250		$	8.66		7.94	$	1,605,684
Granted		1,059,500			4.20
Exercised		(1,576	)		1.67
Forfeited		(418,642	)		8.87
Expired		(215,041	)		10.51

Outstanding at December 31, 2017		2,580,491		$	6.65		7.55	$	803,600

Exercisable at December 31, 2017		1,404,844		$	7.21		6.56	$	692,232

Vested or expected to vest at December 31, 2017		2,580,491		$	6.65		7.55	$	803,600

Schedule of fair value assumptions

Year Ended
December 31, 2017

Year Ended
December 31, 2016

Year Ended
December 31, 2015

Expected volatility

73.87% to 81.04%

71.01% to 74.20%

72.98% to 74.94%

Risk-free interest rate

1.83% to 2.40%

1.23% to 2.40%

1.62% to 2.49%

Expected term

5.3 - 9.5 years

5.3 - 10 years

Expected dividend yield

Summary of stock-based compensation expense


	Three Months Ended September 30, 2018		Three Months Ended September 30, 2017		Nine Months Ended September 30, 2018		Nine Months Ended September 30, 2017
Research and development	$	43,369	$	386,636	$	674,775	$	1,172,655
Selling, general and administrative		235,021		618,145		1,023,548		2,094,224

Total	$	278,390	$	1,004,781	$	1,698,323	$	3,266,879

Total stock-based compensation expense recognized for employee and non-employee restricted common stock, and stock options granted to employees and non-employees is included in the Company’s consolidated statements of operations and comprehensive loss as follows:


	Year Ended December 31, 2017		Year Ended December 31, 2016		Year Ended December 31, 2015
Research and development	$	1,545,737	$	2,435,565	$	3,192,063
Selling, general and administrative		2,673,428		4,137,398		3,405,296

Total	$	4,219,165	$	6,572,963	$	6,597,359

Income taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Schedule of effective income tax rate reconciliation


	Year Ended December 31, 2017			Year Ended December 31, 2016			Year Ended December 31, 2015
Federal income tax expense at statutory rate		35.0	%		35.0	%		35.0	%
State income tax, net of federal benefit		5.0	%		5.0	%		3.4	%
Permanent differences		(0.7	)%		0.0	%		(0.2	)%
Stock-based compensation		(1.9	)%		(2.6	)%		(6.3	)%
Research credits		2.2	%		1.9	%		1.8	%
Other, net		(1.3	)%		(0.1	)%		0.4	%
Payroll Tax Credit Election		(0.7	)%		0.0	%		0.0	%
Change in valuation allowance		(1.1	)%		(39.2	)%		(34.1	)%
Deferred rate change		(36.5	)%		0.0	%		0.0	%

Effective tax rate		0.0	%		0.0	%		0.0	%

Schedule of deferred tax assets and liabilities

The following table presents the significant components of the Company’s deferred tax assets and liabilities:


	December 31, 2017			December 31, 2016
Deferred tax assets:
U.S. and state net operating loss carryforwards	$	24,744,841		$	24,322,172
Accruals and other temporary differences		202,301			529,462
Amortization		35,783			32,171
Stock-based compensation		1,591,131			1,847,441
Tax credit carryforward		1,964,189			1,423,292

Total deferred tax assets		28,538,245			28,154,538
Less valuation allowance		(28,533,755	)		(28,127,611	)

Deferred tax assets		4,490			26,927

Deferred tax liabilities:
Stock-based compensation		(4,490	)		(23,316	)
Depreciation		—			(3,611	)
Accruals and other temporary differences		—			—

Deferred tax liabilities		(4,490	)		(26,927	)

Net deferred tax assets	$	—		$	—

Net loss per share (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Earnings Per Share [Abstract]

Schedule of antidilutive securities excluded from computation of earnings per share


	September 30, 2018		September 30, 2017
Options to purchase common stock		2,580,639		2,701,922
Unvested restricted common stock		2,709		430,439

Total		2,583,348		3,132,361


	Year Ended December 31, 2017		Year Ended December 31, 2016		Year Ended December 31, 2015
Options to purchase common stock		2,580,491		2,156,250		1,824,973
Unvested restricted common stock		174,988		1,196,792		2,202,262

Total		2,755,479		3,353,042		4,027,235

SEGMENT INFORMATION (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Segment Reporting [Abstract]

Schedule of Segment Reporting Information

Information for the Company’s reportable segments for the years ended December 31, 2017, December 31, 2016, and December 31, 2015 are as follows:


Year Ended December 31, 2017	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	1,274,499		—		—	$	1,274,499
Loss from operations	$	8,877,330		16,715,752		9,132,544	$	34,725,626
Interest income, net	$	—		—		291,964	$	291,964


Year Ended December 31, 2016	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	1,010,663		—		—	$	1,010,663
Loss from operations	$	10,023,137		19,620,338		10,242,757	$	39,886,232
Interest income, net	$	—		—		393,109	$	393,109


Year Ended December 31, 2015	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	—		—		—	$	—
Loss from operations	$	7,892,584		12,224,692		9,096,382	$	29,213,658
Interest income, net	$	—		—		72,028	$	72,028

Schedule Of Information For The Company's Operating Segments

Information for the Company’s reportable segments for the three months ended September 30, 2018 and 2017 are as follows:


Three Months Ended September 30, 2018	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	250,991		—		—	$	250,991
Interest income, net	$	—		—		28,210	$	28,210
Loss from operations	$	18,293		864,934		1,783,356	$	2,666,583

Three Months Ended September 30, 2017	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	413,601		—		—	$	413,601
Interest income, net	$	—		—		77,339	$	77,339
Loss from operations	$	2,323,919		4,683,533		2,402,000	$	9,409,452

Information for the Company’s reportable segments for the nine months ended September 30, 2018 and 2017 are as follows:


Nine Months Ended September 30, 2018	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	675,075		—		—	$	675,075
Interest income, net	$	—		—		139,612	$	139,612
Loss from operations	$	1,921,286		11,699,499		6,432,299	$	20,053,084

Nine Months Ended September 30, 2017	Consumer Operations		Drug Development		Corporate		Consolidated
Total revenue	$	991,671		—		—	$	991,671
Interest income, net	$	—		—		227,535	$	227,535
Loss from operations	$	7,072,225		12,472,149		7,088,292	$	26,632,666

Quarterly financial information (unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Schedule of quarterly financial information


	First Quarter Ended March 31, 2017			Second Quarter Ended June 30, 2017			Third Quarter Ended September 30, 2017			Fourth Quarter Ended December 31, 2017
Net product revenue	$	240,292		$	330,688		$	407,241		$	282,752
Other revenue		2,255			4,835			6,360			76

Total revenue		242,547			335,523			413,601			282,828
Costs and expenses:
Cost of product revenue		79,106			145,325			148,756			133,343
Research and development		3,914,974			4,076,220			4,739,360			4,259,357
Selling, general and administrative		4,594,716			4,990,943			4,934,937			3,983,088

Total costs and expenses		8,588,796			9,212,488			9,823,053			8,375,788

Loss from operations		(8,346,249	)		(8,876,965	)		(9,409,452	)		(8,092,960	)
Interest income, net		77,854			72,342			77,339			64,429

Net loss	$	(8,268,395	)	$	(8,804,623	)	$	(9,332,113	)	$	(8,028,531	)

Net loss per share attributable to common stockholders – basic and diluted	$	(0.49	)	$	(0.51	)	$	(0.54	)	$	(0.46	)

Weighted-average number of common shares outstanding – basic and diluted		16,873,512			17,130,264			17,386,249			17,642,646


	First Quarter Ended March 31, 2016			Second Quarter Ended June 30, 2016			Third Quarter Ended September 30, 2016			Fourth Quarter Ended December 31, 2016
Net product revenue	$	—		$	112,685		$	586,134		$	291,099
Other revenue		—			—			12,940			7,805

Total revenue		—			112,685			599,074			298,904

Costs and expenses:
Cost of product revenue		197,020			110,931			221,090			133,706
Research and development		4,387,079			6,094,921			5,665,357			4,230,804
Selling, general and administrative		5,111,695			5,377,784			5,447,847			3,918,661

Total costs and expenses		9,695,794			11,583,636			11,334,294			8,283,171

Loss from operations		(9,695,794	)		(11,470,951	)		(10,735,220	)		(7,984,267	)
Interest income, net		103,333			107,818			97,726			84,232

Net loss	$	(9,592,461	)	$	(11,363,133	)	$	(10,637,494	)	$	(7,900,035	)

Net loss per share attributable to common stockholders – basic and diluted	$	(0.61	)	$	(0.71	)	$	(0.65	)	$	(0.48	)

Weighted-average number of common shares outstanding – basic and diluted		15,843,532			16,105,555			16,361,617			16,619,596

Organization and operations (Detail)		1 Months Ended		3 Months Ended									9 Months Ended		12 Months Ended
Organization and operations (Detail)	Feb. 03, 2015 USD ($) $ / shares shares	Jun. 30, 2018	Feb. 28, 2015 USD ($) $ / shares shares	Sep. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Sep. 30, 2018 USD ($) Segment	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) Segment shares	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of reportable segments \| Segment													2		2
Common stock, shares issued \| shares															0
Proceeds from initial public offering, net of offering costs	$ 79,900,000		$ 79,900,000												$ 0	$ 0	$ 80,435,430
Payments of stock issuance costs			$ 8,000,000
Retained earnings (accumulated deficit)				$ (130,952,530)	$ (111,079,275)				$ (76,645,613)				$ (130,952,530)		(111,079,275)	(76,645,613)
Cash, cash equivalents, and marketable securities					33,315,759										33,315,759
Percentage decrease in company workforce		60.00%											60.00%
Net loss				2,638,373	$ 8,028,531	$ 9,332,113	$ 8,804,623	$ 8,268,395	$ 7,900,035	$ 10,637,494	$ 11,363,133	$ 9,592,461	$ 19,913,472	$ 26,405,131	$ 34,433,662	$ 39,493,123	$ 29,141,630
Cash and cash equivalents				$ 12,961,126									$ 12,961,126
IPO
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock, shares issued \| shares	5,491,191		5,491,191
Common stock, price per share \| $ / shares	$ 16.00		$ 16.00
Over-Allotment Option
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock, shares issued \| shares	91,191		91,191

Summary of significant accounting policies and recent accounting pronouncements - Narrative (Detail)		1 Months Ended	3 Months Ended									9 Months Ended			12 Months Ended				15 Months Ended
	Feb. 03, 2015 USD ($) $ / shares shares	Feb. 28, 2015 USD ($) $ / shares shares	Sep. 30, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) shares	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Sep. 30, 2018 USD ($) shares	Sep. 30, 2017 USD ($)	Sep. 30, 2016	Dec. 31, 2017 USD ($) Segment shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Jan. 31, 2015	Dec. 31, 2017 shares	Jan. 01, 2017 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of operating segments \| Segment															2
Revenue recognition, refund period														21 days					30 days
Sale discounts			$ 2,000		$ 82,000							$ 19,000	$ 202,000		$ 278,000	$ 135,000	$ 0
Advertising expenses			20,000		1,158,000							792,000	3,073,000		3,566,000	2,936,000	0
Cost of product revenue			$ 91,937	$ 133,343	148,756	$ 145,325	$ 79,106	$ 133,706	$ 221,090	$ 110,931	$ 197,020	$ 355,816	373,187		$ 506,530	662,747
Common stock, shares issued \| shares															0
IPO proceeds, net of issuance costs	$ 79,900,000	$ 79,900,000													$ 0	$ 0	$ 80,435,430
Common stock, number of shares issued from conversion of preferred stock, shares \| shares	6,971,108
Common stock, shares authorized \| shares			100,000,000	100,000,000				100,000,000				100,000,000			100,000,000	100,000,000	100,000,000		100,000,000
IPO issuance costs	$ 1,848,737
IPO underwriting discounts and commissions	$ 6,150,134
Reverse stock split conversion ratio																		0.2335
Accounting Policies [Abstract]
Advertising expense			$ 20,000		1,158,000							$ 792,000	3,073,000		$ 3,566,000	$ 2,936,000	$ 0
IPO
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Common stock, shares issued \| shares	5,491,191	5,491,191
Common stock, price per share (in usd per share) \| $ / shares	$ 16.00	$ 16.00
Over-Allotment Option
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Common stock, shares issued \| shares	91,191	91,191
United States
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of operating segments \| Segment															1
Accumulated Deficit \| Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase to retained earnings due to new accounting principle																				$ 2,000
U.S. Federal and State
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating loss carryforwards that will increase additional paid in capital if used to reduce income taxes payable							$ 42,000
Shipping and Handling
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of product revenue			$ 27,000		$ 64,000							$ 81,000	$ 145,000		$ 261,000	$ 170,000	$ 0

Summary of significant accounting policies - Depreciation Over Estimated Useful Life (Detail)	12 Months Ended
	Dec. 31, 2017
Computers and computer equipment
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Laboratory equipment
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Manufacturing equipment
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Minimum \| Laboratory equipment
Property, Plant and Equipment [Line Items]
Estimated useful life	1 year
Maximum \| Laboratory equipment
Property, Plant and Equipment [Line Items]
Estimated useful life	2 years

Summary of significant accounting policies - Summary of changes in accumulated other comprehensive loss (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Equity, beginning balance	$ 59,317,386	$ 92,192,408	$ (6,538,340)
Other comprehensive gain (loss)	367	23,040	(24,654)
Equity, ending balance	29,105,888	59,317,386	92,192,408
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Equity, beginning balance	(1,614)	(24,654)	0
Equity, ending balance	$ (1,247)	$ (1,614)	$ (24,654)

Restricted cash (Details) (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 126,595	$ 126,595
Letter of Credit
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 126,595	$ 126,595

Fair value measurements (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Marketable securities:
Marketable securities		$ 14,129,723	$ 38,658,933
U.S. government agency securities
Marketable securities:
Marketable securities		8,986,259	31,059,491
Commercial paper
Marketable securities:
Marketable securities		4,440,689	6,081,202
Corporate debt securities
Marketable securities:
Marketable securities		702,775	1,518,240
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 2,321,614	5,046,205	11,681,074
Marketable securities:
Total assets	2,321,614	19,175,928	50,340,007
Fair Value, Measurements, Recurring \| U.S. government agency securities
Marketable securities:
Marketable securities		8,986,259	31,059,491
Fair Value, Measurements, Recurring \| Commercial paper
Marketable securities:
Marketable securities		4,440,689	6,081,202
Fair Value, Measurements, Recurring \| Corporate debt securities
Marketable securities:
Marketable securities		702,775	1,518,240
Fair Value, Measurements, Recurring \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	2,321,614	5,046,205	11,681,074
Marketable securities:
Total assets	2,321,614	5,046,205	11,681,074
Fair Value, Measurements, Recurring \| Level 1 \| U.S. government agency securities
Marketable securities:
Marketable securities		0	0
Fair Value, Measurements, Recurring \| Level 1 \| Commercial paper
Marketable securities:
Marketable securities		0	0
Fair Value, Measurements, Recurring \| Level 1 \| Corporate debt securities
Marketable securities:
Marketable securities		0	0
Fair Value, Measurements, Recurring \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0	0
Marketable securities:
Total assets	0	14,129,723	38,658,933
Fair Value, Measurements, Recurring \| Level 2 \| U.S. government agency securities
Marketable securities:
Marketable securities		8,986,259	31,059,491
Fair Value, Measurements, Recurring \| Level 2 \| Commercial paper
Marketable securities:
Marketable securities		4,440,689	6,081,202
Fair Value, Measurements, Recurring \| Level 2 \| Corporate debt securities
Marketable securities:
Marketable securities		702,775	1,518,240
Fair Value, Measurements, Recurring \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0	0
Marketable securities:
Total assets	$ 0	0	0
Fair Value, Measurements, Recurring \| Level 3 \| U.S. government agency securities
Marketable securities:
Marketable securities		0	0
Fair Value, Measurements, Recurring \| Level 3 \| Commercial paper
Marketable securities:
Marketable securities		0	0
Fair Value, Measurements, Recurring \| Level 3 \| Corporate debt securities
Marketable securities:
Marketable securities		$ 0	$ 0

Cash equivalents and marketable securities (Detail)	Dec. 31, 2017 USD ($) Security	Dec. 31, 2016 USD ($)
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 14,130,970	$ 38,660,547
Unrealized Gains	38	2,912
Unrealized Losses	(1,285)	(4,526)
Fair Value	$ 14,129,723	38,658,933
Number of debt securities in an unrealized loss position \| Security	6
Aggregate fair value of debt securities in an unrealized loss position	$ 8,191,315	16,519,620
Number of debt securities in a significant unrealized loss position \| Security	0
U.S. government agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 8,987,254	31,060,710
Unrealized Gains	38	2,912
Unrealized Losses	(1,033)	(4,131)
Fair Value	8,986,259	31,059,491
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,440,689	6,081,202
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	4,440,689	6,081,202
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	703,027	1,518,635
Unrealized Gains	0	0
Unrealized Losses	(252)	(395)
Fair Value	$ 702,775	$ 1,518,240

Inventory (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
Inventory (Detail) - USD ($)	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Raw materials	$ 7,240		$ 7,240		$ 17,411	$ 19,888
Finished goods	216,279		216,279		414,480	434,244
Total inventory	223,519		223,519		431,891	454,132
Write-off of inventory	$ 0	$ 15,000	$ 85,000	$ 34,000	$ 42,000	$ 282,000

Property and equipment, net (Detail) - USD ($)	9 Months Ended		12 Months Ended
Property and equipment, net (Detail) - USD ($)	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Total property and equipment			$ 953,923	$ 879,329
Accumulated depreciation			(622,883)	(323,014)
Property and equipment, net	$ 127,090		331,040	556,315
Depreciation expense	$ 176,954	$ 250,563	324,548	277,231	$ 49,881
Manufacturing equipment
Property, Plant and Equipment [Line Items]
Total property and equipment			421,999	421,999
Computers and computer equipment
Property, Plant and Equipment [Line Items]
Total property and equipment			311,847	276,263
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment			177,886	159,836
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment			13,368	13,368
Capital in progress
Property, Plant and Equipment [Line Items]
Total property and equipment			$ 28,823	$ 7,863

Accrued expenses and other current liabilities - Summary of accrued expenses and other current liabilities (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Phase 2 MND and CMT clinical trial-related costs	$ 609,222	$ 1,850,115
Research and development costs, including other related expenses		2,502,400	$ 938,665
Payroll and employee-related costs	430,560	874,246	1,453,665
Professional fees	284,725	227,980	153,219
Restructuring-related costs	189,927	0
Other research and development-related costs	23,808	652,285
Consumer product-related costs	16,437	107,595	42,024
Total	$ 1,554,679	$ 3,712,221	$ 2,587,573

Commitments and contingencies - Minimum future lease payments (Detail)	Dec. 31, 2017 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2018	$ 466,593
2019	311,062
Total minimum lease payments	$ 777,655

Commitments and contingencies - Narrative (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Rent expense		$ 522,000	$ 337,000	$ 253,000
Percent of gross sales due to related parties	2.00%				2.00%
Royalty expense		25,000	20,000	0
Royalties payable		$ 3,000	$ 4,000	$ 0

Convertible preferred stock (Detail) - USD ($)	3 Months Ended	4 Months Ended	12 Months Ended
Convertible preferred stock (Detail) - USD ($)	May 31, 2014	Oct. 31, 2014	Dec. 31, 2017	Sep. 30, 2018	Dec. 31, 2016	Dec. 31, 2014
Class of Stock [Line Items]
Preferred stock, authorized			10,000,000	10,000,000	10,000,000
Preferred stock, par value			$ 0.0001	$ 0.0001	$ 0.0001
Issuance of stock/IPO proceeds, net of issuance costs			0
Preferred stock, carrying value			$ 0	$ 0	$ 0
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, authorized						16,000,000
Preferred stock, par value						$ 0.0001
Issuance of stock/IPO proceeds, net of issuance costs	15,775,221
Convertible preferred stock, automatic conversion, minimum share price	$ 1.00
Preferred stock, carrying value					15,637,032
Net proceeds from issuance of convertible preferred stock	$ 15,637,032
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, authorized			0			14,500,000
Preferred stock, par value						$ 0.0001
Issuance of stock/IPO proceeds, net of issuance costs		14,078,647
Convertible preferred stock, automatic conversion, minimum share price		$ 1.81
Preferred stock, carrying value					$ 25,394,135
Net proceeds from issuance of convertible preferred stock		$ 25,394,135

Common stock - Narrative (Detail)		1 Months Ended		9 Months Ended	12 Months Ended
Common stock - Narrative (Detail)	Jun. 14, 2018	Apr. 30, 2014 shares	Mar. 31, 2014 USD ($) $ / shares shares	Sep. 30, 2018 Vote $ / shares shares	Dec. 31, 2017 USD ($) Vote $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock, shares sold (shares)					0
Restricted common stock, vesting period (in years)	48 months
Stock issued under Employee Stock Purchase Plan (shares)					0
Equity [Abstract]
Common stock, shares authorized (shares)				100,000,000	100,000,000	100,000,000	100,000,000
Common stock, par value (in usd per share) \| $ / shares				$ 0.0001	$ 0.0001	$ 0.0001
Common stock, number of votes per share \| Vote				1	1
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock, shares sold (shares)		867,314	4,553,415
Restricted common stock, price per share (in usd per share) \| $ / shares			$ 0.0004
Proceeds from sale of restricted common stock to founders \| $			$ 1,950
Restricted common stock, repurchase period					90 days
Restricted common stock, repurchase price (in usd per share) \| $ / shares					$ 0.0004
Restricted common stock, shares outstanding (shares)					5,251,075
Restricted common stock, fair value of shares vested \| $					$ 3,840,000	$ 9,646,000	$ 15,616,000
Restricted stock \| Non-employee Consultants and Advisers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock, shares sold (shares)					0	18,194	0
Restricted common stock, shares outstanding (shares)				15,485	12,860
Restricted common stock, fair value of shares vested \| $					$ 22,000	$ 71,000
Restricted stock \| Vests upon issuance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock, percent vested				25.00%	25.00%
Restricted stock \| Vests ratably over four years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock, percent vested				75.00%	75.00%
Restricted common stock, vesting period (in years)				4 years	4 years

Common stock - Restricted common stock activity (Detail) - Restricted stock - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Number of Shares
Beginning balance, unvested (shares)	169,654	1,185,958
Issued (shares)	0	0
Vested (shares)	(169,654)	(1,016,304)
Forfeited (shares)	0	0
Ending balance, unvested (shares)	0	169,654
Weighted-Average Grant Date Fair Value
Beginning balance, weighted average grant date fair value (in usd per share)	$ 0.10	$ 0.10
Issued, weighted average grant date fair value (in usd per share)	0.00	0.00
Vested, weighted average grant date fair value (in usd per share)	0.10	0.10
Forfeited, weighted average grant date fair value (in usd per share)	0.00	0.00
Ending balance, weighted average grant date fair value (in usd per share)	$ 0.00	$ 0.10
Non-employee Consultants and Advisers
Number of Shares
Beginning balance, unvested (shares)	5,334	10,834
Issued (shares)	0	0
Vested (shares)	(2,625)	(5,500)
Forfeited (shares)	0	0
Ending balance, unvested (shares)	2,709	5,334
Weighted-Average Grant Date Fair Value
Beginning balance, weighted average grant date fair value (in usd per share)	$ 10.51	$ 9.72
Issued, weighted average grant date fair value (in usd per share)	0.00	0.00
Vested, weighted average grant date fair value (in usd per share)	9.95	8.95
Forfeited, weighted average grant date fair value (in usd per share)	0.00	0.00
Ending balance, weighted average grant date fair value (in usd per share)	$ 11.05	$ 10.51

Common stock - Shares reserved for future issuance (Detail) - shares	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Stock-based compensation awards	3,439,820	2,722,573
Employee stock purchase plan	534,274	354,569
Total	4,149,082	4,273,934
Restricted stock
Class of Stock [Line Items]
Vesting of restricted common stock	174,988	1,196,792

Stock-based compensation - Narrative (Detail)		1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
Stock-based compensation - Narrative (Detail)	Jun. 14, 2018 Employee shares	Jun. 01, 2018 Employee Advisors shares	Sep. 30, 2018 USD ($) shares	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) $ / shares shares	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Sep. 30, 2014 shares	Apr. 30, 2014 shares	Mar. 31, 2014 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period (in years)	48 months
Stock-based compensation expense \| $			$ 278,390	$ 1,004,781	$ 1,698,323	$ 3,266,879	$ 4,219,165	$ 6,572,963	$ 6,597,359
Number of stock options granted (shares)	654,544				1,517,544		1,059,500	763,320	994,748
Shares granted, weighted-average grant date fair value (in usd per share) \| $ / shares							$ 2.80	$ 6.35	$ 8.55
Shares exercised (shares)					97,310		1,576	8,516	47,280
Shares exercised, weighted average exercise price (in usd per share) \| $ / shares					$ 1.21		$ 1.67	$ 2.59	$ 8.63
Stock options exercised, intrinsic value \| $							$ 2,606	$ 64,302	$ 149,386
Unrecognized compensation cost \| $			$ 2,481,000		$ 2,481,000		$ 4,533,000
Unrecognized compensation cost, recognition period (in years)					2 years 10 months 24 days		2 years 3 months 4 days
Number of options outstanding (shares)			2,580,639		2,580,639		2,580,491	2,156,250
Number of employees granted options \| Employee	7
Employee stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, contractual term					10 years		10 years
Non-employee Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted to non-employee consultants and members of the Scientific Advisory Board (shares)							0	14,670	10,507
Stock options, vesting period (in years)							4 years
Stock options, contractual term							10 years
Stock-based compensation expense \| $							$ 201,000	$ 370,000	$ 517,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, post termination exercisability extended period	1 year
Minimum \| Employee stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period (in years)					1 year		1 year
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, post termination exercisability extended period	3 years
Maximum \| Employee stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period (in years)					4 years		4 years
2014 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized										2,070,200	1,451,087	116,754
2015 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remaining available for grant of stock awards			1,480,758		1,480,758		859,329
Employee Stock Option, One-Year Post Termination Exercisability
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, post termination exercisability period		3 months
Number of options outstanding (shares)		877,137
Number of employees holding options \| Employee		6
Number of advisers holding options \| Advisors		1
Stock options, post termination exercisability extended period		1 year
Employee Stock Option, Three-Year Post Termination Exercisability
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, post termination exercisability period		3 months
Number of options outstanding (shares)		500,000
Number of employees holding options \| Employee		1
Stock options, post termination exercisability extended period		3 years
Selling, general and administrative \| Employee stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense \| $								$ 285,000

Stock-based compensation - Summary of stock option activity (Detail) - USD ($)		9 Months Ended	12 Months Ended
	Jun. 14, 2018	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Shares
Shares outstanding, Beginning Balance (shares)		2,580,491	2,156,250
Shares granted (shares)	654,544	1,517,544	1,059,500	763,320	994,748
Shares exercised (shares)		(97,310)	(1,576)	(8,516)	(47,280)
Shares forfeited (shares)		(714,699)	(418,642)
Shares expired (shares)		(705,387)	(215,041)
Shares outstanding, Ending Balance (shares)		2,580,639	2,580,491	2,156,250
Shares exercisable (shares)		1,126,248	1,404,844
Shares vested or expected to vest (shares)		2,580,639	2,580,491
Weighted-Average Exercise Price
Shares outstanding, weighted-average exercise price, Beginning Balance (in usd per share)		$ 6.65	$ 8.66
Shares granted, weighted-average exercise price (in usd per share)		2.74	4.20
Shares exercised, weighted-average exercise price (in usd per share)		1.21	1.67	$ 2.59	$ 8.63
Shares forfeited, weighted-average exercise price (in usd per share)		5.96	8.87
Shares expired, weighted-average exercise price (in usd per share)		8.35	10.51
Shares outstanding, weighted-average exercise price, Ending Balance (in usd per share)		4.28	6.65	$ 8.66
Shares exercisable, weighted-average exercise price (in usd per share)		5.92	7.21
Shares vested or expected to vest, weighted-average exercise price (in usd per share)		$ 4.28	$ 6.65
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, weighted-average remaining contractual term (in years)		8 years 26 days	7 years 6 months 18 days	7 years 11 months 9 days
Exercisable, weighted-average remaining contractual term (in years)		6 years 6 months 18 days	6 years 6 months 22 days
Vested or expected to vest, weighted-average remaining contractual term (in years)		8 years 26 days	7 years 6 months 18 days
Outstanding, aggregate intrinsic value		$ 0	$ 803,600	$ 1,605,684
Exercisable, aggregate intrinsic value		0	692,232
Vested or expected to vest, aggregate intrinsic value		$ 0	$ 803,600

Stock-based compensation - Schedule of fair value assumptions (Detail) - Employee stock option	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum (as a percent)	1.83%	1.23%	1.62%
Risk-free interest rate, maximum (as a percent)	2.40%	2.40%	2.49%
Expected dividend yield (as a percent)	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility (as a percent)	73.87%	71.01%	72.98%
Expected term (in years)	5 years 3 months 18 days	5 years 3 months 18 days	5 years 3 months 18 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility (as a percent)	81.04%	74.20%	74.94%
Expected term (in years)	9 years 6 months	10 years	10 years

Stock-based compensation - Summary of stock-based compensation expense (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Service Share-Based Compensation Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 278,390	$ 1,004,781	$ 1,698,323	$ 3,266,879	$ 4,219,165	$ 6,572,963	$ 6,597,359
Research and development
Employee Service Share-Based Compensation Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	43,369	386,636	674,775	1,172,655	1,545,737	2,435,565	3,192,063
Selling, general and administrative
Employee Service Share-Based Compensation Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 235,021	$ 618,145	$ 1,023,548	$ 2,094,224	$ 2,673,428	$ 4,137,398	$ 3,405,296

Income taxes - Narrative (Detail) - USD ($)	3 Months Ended	9 Months Ended		12 Months Ended
Income taxes - Narrative (Detail) - USD ($)	Mar. 31, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Taxes Disclosure [Line Items]
Decrease in net deferred tax asset				$ 12,600,000
Net impact to income tax expense				0
Increase (decrease) in valuation allowance				406,000
Payroll tax credit				22,000
Income tax provision (benefit)		$ 0	$ 0
U.S. Federal
Income Taxes Disclosure [Line Items]
Net operating loss carryforward				91,200,000
Research and development tax credit carryforwards				1,600,000
U.S. State
Income Taxes Disclosure [Line Items]
Net operating loss carryforward				90,400,000
Research and development tax credit carryforwards				428,000
Operating loss carryforward tax affected				$ 7,100,000
U.S. Federal and State
Income Taxes Disclosure [Line Items]
Operating loss carryforwards that will increase additional paid in capital if used to reduce income taxes payable	$ 42,000

Income taxes - Schedule of effective income tax rate reconciliation (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal income tax expense at statutory rate	35.00%	35.00%	35.00%
State income tax, net of federal benefit	5.00%	5.00%	3.40%
Permanent differences	(0.70%)	0.00%	(0.20%)
Stock-based compensation	(1.90%)	(2.60%)	(6.30%)
Research credits	2.20%	1.90%	1.80%
Other, net	(1.30%)	(0.10%)	0.40%
Payroll Tax Credit Election	(0.70%)	0.00%	0.00%
Change in valuation allowance	(1.10%)	(39.20%)	(34.10%)
Deferred rate change	(36.50%)	0.00%	0.00%
Effective tax rate	0.00%	0.00%	0.00%

Income taxes - Schedule of deferred tax assets and liabilities (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
U.S. and state net operating loss carryforwards	$ 24,744,841	$ 24,322,172
Accruals and other temporary differences	202,301	529,462
Amortization	35,783	32,171
Stock-based compensation	1,591,131	1,847,441
Tax credit carryforward	1,964,189	1,423,292
Total deferred tax assets	28,538,245	28,154,538
Less valuation allowance	(28,533,755)	(28,127,611)
Deferred tax assets	4,490	26,927
Deferred tax liabilities:
Stock-based compensation	(4,490)	(23,316)
Depreciation	0	(3,611)
Accruals and other temporary differences	0	0
Deferred tax liabilities	(4,490)	(26,927)
Net deferred tax assets	$ 0	$ 0

Net loss per share (Detail) - shares	9 Months Ended		12 Months Ended
Net loss per share (Detail) - shares	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)	2,583,348	3,132,361	2,755,479	3,353,042	4,027,235
Employee stock option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)	2,580,639	2,701,922	2,580,491	2,156,250	1,824,973
Restricted stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)	2,709	430,439	174,988	1,196,792	2,202,262

Segment Information (Detail)	3 Months Ended									9 Months Ended		12 Months Ended
Segment Information (Detail)	Sep. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Sep. 30, 2018 USD ($) Segment	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) Segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments \| Segment										2		2
Total revenue	$ 250,991		$ 413,601							$ 675,075	$ 991,671	$ 1,274,499	$ 1,010,663
Interest income, net	28,210	$ 64,429	77,339	$ 72,342	$ 77,854	$ 84,232	$ 97,726	$ 107,818	$ 103,333	139,612	227,535	291,964	393,109	$ 72,028
Loss from operations	2,666,583	$ 8,092,960	9,409,452	$ 8,876,965	$ 8,346,249	$ 7,984,267	$ 10,735,220	$ 11,470,951	$ 9,695,794	20,053,084	26,632,666	34,725,626	39,886,232	29,213,658
Operating Segments \| Consumer Operations
Segment Reporting Information [Line Items]
Total revenue	250,991		413,601							675,075	991,671	1,274,499	1,010,663
Loss from operations	18,293		2,323,919							1,921,286	7,072,225	8,877,330	10,023,137	7,892,584
Operating Segments \| Drug Development
Segment Reporting Information [Line Items]
Loss from operations	864,934		4,683,533							11,699,499	12,472,149	16,715,752	19,620,338	12,224,692
Corporate
Segment Reporting Information [Line Items]
Interest income, net	28,210		77,339							139,612	227,535	291,964	393,109	72,028
Loss from operations	$ 1,783,356		$ 2,402,000							$ 6,432,299	$ 7,088,292	$ 9,132,544	$ 10,242,757	$ 9,096,382

Related parties (Detail) - USD ($)	1 Months Ended	12 Months Ended
Related parties (Detail) - USD ($)	Mar. 31, 2014	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Percent of gross sales due to related parties	2.00%				2.00%
Royalty expense		$ 25,000	$ 20,000	$ 0
Royalties payable		$ 3,000	4,000	0
Affiliated Entity
Related Party Transaction [Line Items]
License fees received			$ 32,000	$ 61,000

Quarterly financial information (unaudited) (Detail) - USD ($)	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Total revenue		$ 282,828	$ 413,601	$ 335,523	$ 242,547	$ 298,904	$ 599,074	$ 112,685
Costs and expenses:
Cost of product revenue	$ 91,937	133,343	148,756	145,325	79,106	133,706	221,090	110,931	$ 197,020	$ 355,816	$ 373,187	$ 506,530	$ 662,747
Research and development	865,765	4,259,357	4,739,360	4,076,220	3,914,974	4,230,804	5,665,357	6,094,921	4,387,079	11,720,535	12,730,554	16,989,911	20,378,161	$ 12,749,379
Selling, general and administrative	1,959,872	3,983,088	4,934,937	4,990,943	4,594,716	3,918,661	5,447,847	5,377,784	5,111,695	8,651,808	14,520,596	18,503,684	19,855,987	16,464,279
Total costs and expenses	2,917,574	8,375,788	9,823,053	9,212,488	8,588,796	8,283,171	11,334,294	11,583,636	9,695,794	20,728,159	27,624,337	36,000,125	40,896,895	29,213,658
Loss from operations	(2,666,583)	(8,092,960)	(9,409,452)	(8,876,965)	(8,346,249)	(7,984,267)	(10,735,220)	(11,470,951)	(9,695,794)	(20,053,084)	(26,632,666)	(34,725,626)	(39,886,232)	(29,213,658)
Interest income, net	28,210	64,429	77,339	72,342	77,854	84,232	97,726	107,818	103,333	139,612	227,535	291,964	393,109	72,028
Net loss	$ (2,638,373)	$ (8,028,531)	$ (9,332,113)	$ (8,804,623)	$ (8,268,395)	$ (7,900,035)	$ (10,637,494)	$ (11,363,133)	$ (9,592,461)	$ (19,913,472)	$ (26,405,131)	$ (34,433,662)	$ (39,493,123)	$ (29,141,630)
Net loss per share attributable to common stockholders - basic and diluted	$ (0.15)	$ (0.46)	$ (0.54)	$ (0.51)	$ (0.49)	$ (0.48)	$ (0.65)	$ (0.71)	$ (0.61)	$ (1.11)	$ (1.54)	$ (1.99)	$ (2.43)	$ (2.08)
Weighted-average number of common shares outstanding - basic and diluted	18,066,548	17,642,646	17,386,249	17,130,264	16,873,512	16,619,596	16,361,617	16,105,555	15,843,532	17,999,877	17,131,887	17,260,626	16,233,985	14,032,916
Net product revenue
Quarterly Financial Information Disclosure [Abstract]
Total revenue		$ 282,752	$ 407,241	$ 330,688	$ 240,292	$ 291,099	$ 586,134	$ 112,685
Other revenue
Quarterly Financial Information Disclosure [Abstract]
Total revenue		$ 76	$ 6,360	$ 4,835	$ 2,255	$ 7,805	$ 12,940

Summary of significant accounting policies and recent accounting pronouncements - Summary of cash and cash equivalents and restricted cash (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Regulatory Assets [Abstract]
Cash and cash equivalents	$ 12,961,126	$ 19,186,036		$ 22,416,040	$ 66,686,695	$ 33,854,153
Restricted cash	126,595	126,595		126,595
Cash, cash equivalents and restricted cash shown on the condensed consolidated statement of cash flows	$ 13,087,721	$ 19,312,631	$ 20,405,319	$ 22,542,635

Revenue from contracts with customers (Detail)	3 Months Ended			6 Months Ended	9 Months Ended		12 Months Ended
Revenue from contracts with customers (Detail)	Sep. 30, 2018 USD ($)	Sep. 30, 2018 USD ($) Customer	Sep. 30, 2017 USD ($) Customer	Jun. 18, 2018	Sep. 30, 2018 USD ($) Customer	Sep. 30, 2017 USD ($) Customer	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jan. 01, 2018 USD ($)
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Increase to retained earnings due to adoption of Topic 606	$ (130,952,530)	$ (130,952,530)			$ (130,952,530)		$ (111,079,275)	$ (76,645,613)
Total revenue		250,991	$ 413,601		675,075	$ 991,671	1,274,499	1,010,663
Refund period	14 days			30 days
Discounts to customers		$ 2,000	$ 82,000		$ 19,000	$ 202,000	$ 278,000	$ 135,000	$ 0
Number of customers that represented greater than 10% of total revenue \| Customer		0	0		0	0
Difference between Revenue Guidance in Effect before and after Topic 606 \| Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Increase to retained earnings due to adoption of Topic 606										$ 40,000
Decrease in deferred revenue										70,000
Decrease in deferred costs from product revenue										$ 30,000
Total revenue		$ (1,000)			$ (29,000)

Accrued expenses and other current liabilities - Narrative (Detail)	1 Months Ended	3 Months Ended		6 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($) Employee	Sep. 30, 2018 USD ($)	Sep. 30, 2018 USD ($) Employee	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Accrued research and development expense			$ 609,222	$ 609,222	$ 609,222		$ 1,850,115
Percentage decrease in company workforce	60.00%				60.00%
Cash retention bonuses payable	$ 1,210,000
Cash retention bonuses payable upon change in control	500,000
Cash retention bonuses payable upon employees in good standing	710,000
Severance benefits payable upon change in control and termination without cause	$ 1,125,000
Restructuring charges			$ 212,000	$ 1,130,000	$ 1,130,000
Number of retained employees \| Employee			7		7
Ongoing Termination Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 12,000		$ 851,000
One-time termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges			77,000		99,000
Employee retention benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges			147,000		164,813
Other
Restructuring Cost and Reserve [Line Items]
Restructuring charges					14,995
Research and development
Restructuring Cost and Reserve [Line Items]
Restructuring charges			133,000		837,000
Selling, general and administrative
Restructuring Cost and Reserve [Line Items]
Restructuring charges			79,000		293,000
Consumer Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges			19,000		75,000
Drug Development
Restructuring Cost and Reserve [Line Items]
Restructuring charges			133,000		837,000
Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 60,000		$ 218,000
Scenario, Forecast
Restructuring Cost and Reserve [Line Items]
Severance benefits payable upon change in control and termination without cause						$ 1,125,000
Restructuring charges		$ 50,000
Restructuring charges to be incurred if change of control occurs						500,000
Scenario, Forecast \| Consumer Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges						113,000
Scenario, Forecast \| Drug Development
Restructuring Cost and Reserve [Line Items]
Restructuring charges						1,048,000
Scenario, Forecast \| Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring charges						2,192,000
Scenario, Forecast \| Minimum
Restructuring Cost and Reserve [Line Items]
Restructuring charges						1,173,000
Scenario, Forecast \| Maximum
Restructuring Cost and Reserve [Line Items]
Restructuring charges						$ 3,353,000

Accrued expenses and other current liabilities - Summary of restructuring reserve activity (Detail) - USD ($)	3 Months Ended	6 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2018
Restructuring Reserve [Roll Forward]
Opening balance			$ 0
Charges	$ 212,000	$ 1,130,000	1,130,000
Payments			(940,518)
Accrued restructuring balance as of September 30, 2018	189,927	$ 189,927	189,927
Employee termination benefits
Restructuring Reserve [Roll Forward]
Charges			950,637
Employee retention benefits
Restructuring Reserve [Roll Forward]
Charges	$ 147,000		164,813
Other
Restructuring Reserve [Roll Forward]
Charges			$ 14,995