Salarius Pharmaceuticals (SLRX) S-4 14 Feb 19 Registration of securities issued in business combination transactions Financial data

Document and Entity Information

Document and Entity Information	9 Months Ended
	Sep. 30, 2018
Document And Entity Information [Abstract]
Document Type	S4
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Trading Symbol	FLKS
Entity Registrant Name	Flex Pharma, Inc.
Entity Central Index Key	1,615,219
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true

CONDENSED CONSOLIDATED BALANCE

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 BALANC_2

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 STATEMEN

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 STATEM_2

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)

CONSOLIDATED STATEMENTS OF CONV

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 StockPreferred Stock	Series A Preferred StockCommon Stock	Series A Preferred StockAdditional Paid-In Capital	Series B Preferred Stock	Series B Preferred StockPreferred Stock	Series B Preferred StockCommon Stock	Series B Preferred StockAdditional 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 CO_2

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

CONDENSED CONSOLIDATED STATEM_3

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

Organization and operations	9 Months Ended	12 Months Ended
	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 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 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 10-K. 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	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, FLX-787 ® FLX-787, FLX-787, 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 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 accounti

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 10-K”), 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 co-packer Restructuring-related costs The Company records employee termination costs in accordance with Accounting Standards Codification (“ASC”) Topic 712, “ Compensation—Nonretirement and Postemployment Benefits” on-going one-time Exit or Disposal Cost Obligations” 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”) Revenue Recognition (“ASC 605”) In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) In July 2018, the FASB issued ASU No. 2018-10, Codification Improvements to Topic 842, Leases. No. 2016-02. No. 2018-11, Leases (Topic 842): Targeted Improvements. right-of-use In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments No. 2016-15 No. 2016-15 In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows No. 2016-18 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, December 31, 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 No. 2017-09 In June 2018, the FASB issued ASU No. 2018-07, Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting No. 2018-07”). non-employees No. 2018-07 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. Fair Value Measurement No. 2018-13 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 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 co-packing 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 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 Revenue Revenue is comprised of net product revenue and other revenue. Net product revenue includes sales of HOTSHOT finished goods to e-commerce e-commerce e-commerce e-commerce e-commerce 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 in-bound 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 The Company outsources the manufacture of HOTSHOT to a co-packer. 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 co-packer 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 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 non-employees Topic 505-50, Equity-Based Payments to Non-Employees non-employee non-employee non-employee re-measurement 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 Prior to adoption of ASU No. 2016-09 Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting No. 2016-09 Income taxes Income taxes are recorded in accordance with FASB ASC Topic 740, Income Taxes 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 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 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) No. 2016-08, Revenue from Contracts with Customers, Principal versus Agent Considerations (Reporting Revenue Gross versus Net), No. 2016-08 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 e-commerce e-commerce 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) In February 2016, the FASB issued ASU No. 2016-02, Leases right-of-use In March 2016, the FASB issued ASU No. 2016-09, Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments ASU 2016-15 In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows In May 2017, the FASB issued ASU 2017-09, Stock Compensation (Topic 718): Scope of Modification Accounting 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. 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 Reverse stock split In January 2015, the Company effected a one-for-4.2825 paid-in 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

Restricted cash	12 Months Ended
	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

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, 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, 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, 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 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 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 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 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.

Cash equivalents and marketable

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 Investments – Debt and Equity Securities 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 Unrealized Unrealized 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 Investments – Debt and Equity Securities 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. Marketable securities at December 31, 2017 and December 31, 2016 consisted of the following: Amortized Unrealized Unrealized 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 Unrealized Unrealized 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

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, December 31, 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, December 31, 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

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, December 31, 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 curr

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, December 31, 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 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 one-time 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 one-time 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. 10b-5 FLX-787	8. ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES Accrued expenses and other current liabilities consist of the following: December 31, December 31, 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

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

Convertible preferred stock	12 Months Ended
	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

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 re-measured re-valuation The following is a summary of restricted common stock activity: Number of Shares Weighted- 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 non-employees re-measured No. 2018-07 non-employees The following is a summary of restricted common stock activity: Number of Shares Weighted- 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 re-measured The following is a summary of restricted common stock activity: Number of Weighted-Average 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 non-employee non-employees re-measured The following is a summary of restricted common stock activity: Number of Weighted-Average 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

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 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 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 re-measured No. 2018-07 non-employees The following table summarizes stock option activity for employees and non-employees Shares Weighted- Exercise Weighted- Remaining Contractual Term Aggregate 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 non-employees Three Months Three Months Nine Months Nine Months 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 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 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 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 There were no stock options issued to non-employee non-employee non-employee 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 re-measured non-employees Shares Weighted-Average Weighted-Average Aggregate 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 Year Ended Year Ended 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 5.3 - 10 5.3 - 10 Expected dividend yield 0% 0% 0% Total stock-based compensation expense recognized for employee and non-employee non-employees Year Ended Year Ended Year Ended 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 non-employee non-employee

Income taxes

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	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 Year Ended Year Ended 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, December 31, 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 ASU 2016-09 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

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 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 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 September 30, September 30, 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 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 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. The following potentially dilutive securities outstanding, prior to the use of the treasury stock method or if-converted Year Ended Year Ended Year Ended 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

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. 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 Drug 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 Drug 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 Drug 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 Drug 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 Drug 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 Drug 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 Drug 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

Related parties	12 Months Ended
	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

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 Second Quarter 2017 Third Quarter Fourth 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 Second Quarter 2016 Third Quarter Fourth 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

Subsequent events	12 Months Ended
	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 cus

Revenue from contracts with customers	9 Months Ended
	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 e-commerce e-commerce 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 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 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 e-commerce 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 accoun_2

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 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”).	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”).
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. 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
Principles of consolidation	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.	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.
Concentrations of risk, Concentrations of credit risk and off-balance sheet risk		Concentrations of credit risk and off-balance 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 Concentration of risk The Company outsources the manufacture of HOTSHOT to a single co-packer co-packing
Segment information		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.
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		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.
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 Cost of product revenue includes the cost of raw materials utilized to produce HOTSHOT, co-packing in-bound
Inventory		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 The Company outsources the manufacture of HOTSHOT to a co-packer. 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 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 co-packer	Shipping and handling costs Shipping and handling costs related to the movement of inventory to the Company’s co-packer co-packer
Property and equipment		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 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 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.
Research and development expense		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		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 non-employees Topic 505-50, Equity-Based Payments to Non-Employees non-employee non-employee non-employee re-measurement 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 Prior to adoption of ASU No. 2016-09 Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting No. 2016-09
Income taxes		Income taxes Income taxes are recorded in accordance with FASB ASC Topic 740, Income Taxes 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		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 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 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.
Recent accounting pronouncements	Recent accounting pronouncements In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (“ASC 606”) Revenue Recognition (“ASC 605”) In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) In July 2018, the FASB issued ASU No. 2018-10, Codification Improvements to Topic 842, Leases. No. 2016-02. No. 2018-11, Leases (Topic 842): Targeted Improvements. right-of-use In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments No. 2016-15 No. 2016-15 In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows No. 2016-18 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, December 31, 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 No. 2017-09 In June 2018, the FASB issued ASU No. 2018-07, Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting No. 2018-07”). non-employees No. 2018-07 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. Fair Value Measurement No. 2018-13 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.	Recent accounting pronouncements In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) No. 2016-08, Revenue from Contracts with Customers, Principal versus Agent Considerations (Reporting Revenue Gross versus Net), No. 2016-08 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 e-commerce e-commerce 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) In February 2016, the FASB issued ASU No. 2016-02, Leases right-of-use In March 2016, the FASB issued ASU No. 2016-09, Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments ASU 2016-15 In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows In May 2017, the FASB issued ASU 2017-09, Stock Compensation (Topic 718): Scope of Modification Accounting 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.
Subsequent events		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).
Fair value measurements		The Company records cash equivalents and marketable securities at fair value. ASC Topic 820, Fair Value Measurements and Disclosures 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.
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 Investments – Debt and Equity Securities 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.
Accounts receivable	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.
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 The Company records employee termination costs in accordance with Accounting Standards Codification (“ASC”) Topic 712, “ Compensation—Nonretirement and Postemployment Benefits” on-going one-time Exit or Disposal Cost Obligations” 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.

Summary of significant accoun_3

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	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, December 31, 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

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, 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, 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 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 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 marketab_2

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 Unrealized Unrealized 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 Unrealized Unrealized 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 Unrealized Unrealized 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)

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, December 31, 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, December 31, Raw materials $ 17,411 $ 19,888 Finished goods 414,480 434,244 Total inventory $ 431,891 $ 454,132

Property and equipment, net (Ta

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 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, December 31, 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 cu_2

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, December 31, 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, December 31, 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, December 31, 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 (

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)

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- 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- 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 Weighted-Average 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 Weighted-Average 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

Stock-based compensation (Table

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 Shares Weighted- Exercise Weighted- Remaining Contractual Term Aggregate 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 Shares Weighted-Average Weighted-Average Aggregate 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		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 Year Ended Year Ended 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 5.3 - 10 5.3 - 10 Expected dividend yield 0% 0% 0%
Summary of stock-based compensation expense	Total stock-based compensation expense recognized for employee and non-employee non-employees Three Months Three Months Nine Months Nine Months 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 non-employees Year Ended Year Ended Year Ended 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)

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of effective income tax rate reconciliation	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 Year Ended Year Ended 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, December 31, 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)

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	The following potentially dilutive securities outstanding, prior to the use of the treasury stock method or if-converted September 30, September 30, 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	The following potentially dilutive securities outstanding, prior to the use of the treasury stock method or if-converted Year Ended Year Ended Year Ended 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)

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 Drug 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 Drug 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 Drug 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 Drug 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 Drug 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 Drug 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 Drug 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 informati_2

Quarterly financial information (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly financial information	First Quarter Second Quarter 2017 Third Quarter Fourth 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 Second Quarter 2016 Third Quarter Fourth 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 (De

Organization and operations (Detail)	Feb. 03, 2015USD ($)$ / sharesshares	Jun. 30, 2018	Feb. 28, 2015USD ($)$ / sharesshares	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Sep. 30, 2018USD ($)Segment	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)Segmentshares	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
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		$ 16
Over-Allotment Option
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock, shares issued | shares	91,191		91,191

Summary of significant accoun_4

Summary of significant accounting policies and recent accounting pronouncements - Narrative (Detail)	Feb. 03, 2015USD ($)$ / sharesshares	Feb. 28, 2015USD ($)$ / sharesshares	Sep. 30, 2018USD ($)shares	Dec. 31, 2017USD ($)shares	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)shares	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Sep. 30, 2018USD ($)shares	Sep. 30, 2017USD ($)	Sep. 30, 2016	Dec. 31, 2017USD ($)Segmentshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)shares	Jan. 31, 2015	Dec. 31, 2017shares	Jan. 01, 2017USD ($)
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	$ 16
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 accoun_5

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 accoun_6

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) (Deta

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

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 marketab_3

Cash equivalents and marketable securities (Detail)	Dec. 31, 2017USD ($)Security	Dec. 31, 2016USD ($)
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)

Inventory (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
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 (De

Property and equipment, net (Detail) - USD ($)	9 Months Ended		12 Months Ended
	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 cu_3

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 -

Commitments and contingencies - Minimum future lease payments (Detail)	Dec. 31, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,018	$ 466,593
2,019	311,062
Total minimum lease payments	$ 777,655

Commitments and contingencies_2

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 (De

Convertible preferred stock (Detail) - USD ($)	3 Months Ended	4 Months Ended	12 Months Ended
	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
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 (Detai

Common stock - Narrative (Detail)	Jun. 14, 2018	Apr. 30, 2014shares	Mar. 31, 2014USD ($)$ / sharesshares	Sep. 30, 2018Vote$ / sharesshares	Dec. 31, 2017USD ($)Vote$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)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 commo

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	0
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	0
Ending balance, weighted average grant date fair value (in usd per share)	$ 0	$ 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	0
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	0
Ending balance, weighted average grant date fair value (in usd per share)	$ 11.05	$ 10.51

Common stock - Shares reserved

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 - Narr

Stock-based compensation - Narrative (Detail)

Jun. 14, 2018Employeeshares

Jun. 01, 2018EmployeeAdvisorsshares

Sep. 30, 2018USD ($)shares

Sep. 30, 2017USD ($)

Sep. 30, 2018USD ($)$ / sharesshares

Sep. 30, 2017USD ($)

Dec. 31, 2017USD ($)$ / sharesshares

Dec. 31, 2016USD ($)$ / sharesshares

Dec. 31, 2015USD ($)$ / sharesshares

Sep. 30, 2014shares

Apr. 30, 2014shares

Mar. 31, 2014shares

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 - Summ

Stock-based compensation - Summary of stock option activity (Detail) - USD ($)	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 - Sche

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 - Su_2

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 (Detai

Income taxes - Narrative (Detail) - USD ($)	3 Months Ended	9 Months Ended		12 Months Ended
	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 effe

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 defe

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)

Net loss per share (Detail) - shares	9 Months Ended		12 Months Ended
	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)

Segment Information (Detail)	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Sep. 30, 2018USD ($)Segment	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)Segment	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
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)

Related parties (Detail) - USD ($)	1 Months Ended	12 Months Ended
	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 informati_3

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 accoun_7

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 c_2

Revenue from contracts with customers (Detail)	3 Months Ended			6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)Customer	Sep. 30, 2017USD ($)Customer	Jun. 18, 2018	Sep. 30, 2018USD ($)Customer	Sep. 30, 2017USD ($)Customer	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Jan. 01, 2018USD ($)
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 cu_4

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, 2018USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)Employee	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)Employee	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
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 cu_5

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