Salarius Pharmaceuticals (SLRX) 10-K 8 Mar 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Mar. 03, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Entity Registrant Name	Flex Pharma, Inc.
Entity Central Index Key	1,615,219
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		17,970,590
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 104.8

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 22,416,040	$ 66,686,695
Marketable securities	38,658,933	24,652,348
Accounts receivable	12,181	0
Inventory	454,132	0
Prepaid expenses and other current assets	925,983	908,574
Total current assets	62,467,269	92,247,617
Marketable securities	0	2,312,949
Property and equipment, net	556,315	382,437
Other assets	64,800	0
Restricted cash	126,595	126,835
Total assets	63,214,979	95,069,838
Current liabilities:
Accounts payable	1,192,183	875,646
Accrued expenses and other current liabilities	2,587,573	1,947,374
Deferred revenue	88,344	0
Deferred rent, current portion	21,095	24,381
Total current liabilities	3,889,195	2,847,401
Deferred rent, net of current portion	8,398	14,587
Other long term liabilities	0	15,442
Total liabilities	3,897,593	2,877,430
Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized at December 31, 2016 and December 31, 2015; none issued or outstanding at December 31, 2016 and December 31, 2015	0	0
Common stock, $0.0001 par value; 100,000,000 shares authorized at December 31, 2016 and December 31, 2015, 17,970,590 and 17,943,880 shares issued at December 31, 2016 and December 31, 2015, respectively, and 16,773,798 and 15,741,618 shares outstanding at December 31, 2016 and December 31, 2015, respectively	1,678	1,574
Additional paid-in capital	135,962,935	129,367,978
Accumulated other comprehensive loss	(1,614)	(24,654)
Accumulated deficit	(76,645,613)	(37,152,490)
Total stockholders' equity	59,317,386	92,192,408
Total liabilities and stockholders' equity	$ 63,214,979	$ 95,069,838

CONSOLIDATED BALANCE SHEET (PAR

CONSOLIDATED BALANCE SHEET (PARENTHETICAL) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Preferred stock, authorized (shares)	10,000,000	10,000,000
Preferred stock, issued (shares)	0	0
Preferred stock, shares outstanding (shares)	0	0
Common stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (shares)	100,000,000	100,000,000
Common stock, shares issued (shares)	17,970,590	17,943,880
Common stock, shares outstanding (shares)	16,773,798	15,741,618

CONSOLIDATED STATEMENT OF OPERA

CONSOLIDATED STATEMENT OF OPERATIONS - USD ($)	10 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net product revenue	$ 0	$ 989,918	$ 0
Other revenue	0	20,745	0
Total revenue	0	1,010,663	0
Costs and expenses:
Cost of product revenue	0	662,747	0
Research and development	4,003,911	20,378,161	12,749,379
Selling, general and administrative	4,025,895	19,855,987	16,464,279
Total costs and expenses	8,029,806	40,896,895	29,213,658
Loss from operations	(8,029,806)	(39,886,232)	(29,213,658)
Interest income, net	18,946	393,109	72,028
Net loss	(8,010,860)	(39,493,123)	(29,141,630)
Net loss attributable to common stockholders	$ (8,010,860)	$ (39,493,123)	$ (29,141,630)
Net loss per share attributable to common stockholders - basic and diluted (in usd per share)	$ (4.57)	$ (2.43)	$ (2.08)
Weighted-average number of common shares outstanding — basic and diluted	1,753,024	16,233,985	14,032,916

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($)	10 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (8,010,860)	$ (39,493,123)	$ (29,141,630)
Other Comprehensive gain (loss):
Unrealized gain (loss) on available-for-sale securities	0	23,040	(24,654)
Other comprehensive gain	0	23,040	(24,654)
Comprehensive loss	$ (8,010,860)	$ (39,470,083)	$ (29,166,284)

CONSOLIDATED STATEMENT OF CONVE

CONSOLIDATED STATEMENT OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - 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 Feb. 26, 2014		0						0				0
Equity, beginning balance at Feb. 26, 2014	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0		$ 0				$ 0
Common stock, shares outstanding, beginning balance at Feb. 26, 2014			0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock/IPO proceeds, net of issuance costs (in shares)								15,775,221				14,078,647
Issuance of stock/IPO proceeds, net of issuance costs								$ 15,637,032				$ 25,394,135
Sale of restricted common stock to founders	2,321			2,321
Vesting of restricted common stock (in shares)			2,202,139
Vesting of restricted common stock	0		$ 220	(220)
Issuance of common stock from option exercises (in shares)			13,572
Issuance of common stock from option exercises	8,138		$ 1	8,137
Stock-based compensation expense	1,462,061			1,462,061
Net loss	(8,010,860)					(8,010,860)
Preferred stock, shares outstanding, ending balance at Dec. 31, 2014		0						15,775,221				14,078,647
Equity, ending 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, ending balance at Dec. 31, 2014			2,215,711
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of preferred stock to common stock (in 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 (in 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 (in shares)			1,016,328
Vesting of restricted common stock	$ 0		$ 102	(102)
Issuance of common stock from option exercises (in 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				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		15,741,618
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted common stock (in shares)			1,023,664
Vesting of restricted common stock	$ 0		$ 102	(102)
Issuance of common stock from option exercises (in 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

CONSOLIDATED STATEMENT OF CONV7

CONSOLIDATED STATEMENT OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (PARENTHETICAL) - USD ($)	10 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015
Issuance costs		$ 7,998,871
Series A Preferred Stock
Issuance costs	$ 138,189
Series B Preferred Stock
Issuance costs	$ 55,835

CONSOLIDATED STATEMENT OF CASH

CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($)	10 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Operating activities
Net loss	$ (8,010,860)	$ (39,493,123)	$ (29,141,630)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	11,997	277,231	49,881
Stock-based compensation expense	1,462,061	6,572,963	6,597,359
Amortization of premium on investments	0	16,161	9,523
Other non-cash items	55,221	3,434	4,123
Changes in operating assets and liabilities:
Restricted cash	(126,808)	240	(27)
Accounts receivable	0	(12,181)	0
Inventory	0	(454,132)	0
Prepaid expenses and other current assets	(370,396)	(17,409)	(538,178)
Other assets	(50,000)	(64,800)	100,103
Accounts payable	254,253	309,437	621,393
Accrued expenses and other current liabilities	220,375	746,879	1,570,216
Deferred revenue	0	88,344	0
Deferred rent	57,849	(9,475)	(18,881)
Other long term liabilities	15,442	(15,442)	0
Net cash used in operating activities	(6,480,866)	(32,051,873)	(20,746,118)
Investing activities
Purchases of marketable securities	0	(38,682,081)	(39,397,769)
Proceeds from maturities and sales of marketable securities	0	26,995,324	12,398,295
Purchases of property and equipment	(76,141)	(559,378)	(265,617)
Proceeds from sales of property and equipment	0	5,255	0
Net cash used in investing activities	(76,141)	(12,240,880)	(27,265,091)
Financing activities
Proceeds from initial public offering, net of offering costs	0	0	80,435,430
Proceeds from sale of restricted common stock to founders	2,321	0	0
Proceeds from exercise of common stock		22,098	8,321
Proceeds from early exercise of common stock	8,138	0	400,000
Deferred IPO issuance costs	(575,245)	0	0
Net cash provided by financing activities	40,411,160	22,098	80,843,751
Net (decrease) increase in cash and cash equivalents	33,854,153	(44,270,655)	32,832,542
Cash and cash equivalents at beginning of period		66,686,695	33,854,153
Cash and cash equivalents at end of period	33,854,153	22,416,040	66,686,695
Supplemental cash flow information
Property and equipment purchases included in accounts payable and accrued expense	21,000	7,100	106,680
IPO issuance costs paid in cash through December 31, 2014	0	0	575,245
IPO issuance costs included in accounts payable and accrued expenses	499,549	0	0
Issuance of Series A convertible preferred stock in satisfaction of accounts payable	55,221	0	0
Series A Preferred Stock
Financing activities
Proceeds from issuance of convertible preferred stock, net of issuance costs	15,581,811	0	0
Series B Preferred Stock
Financing activities
Proceeds from issuance of convertible preferred stock, net of issuance costs	$ 25,394,135	$ 0	$ 0

Organization and operations

Organization and operations	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and operations	Organization and operations The Company Flex Pharma, Inc. (the "Company") is a biotechnology company that is developing innovative and proprietary treatments for muscle cramps and spasms associated with severe neurological conditions and exercise-associated muscle cramps. The Company's lead drug product candidate, FLX-787, is currently in exploratory Phase 2 clinical trials in Australia in patients with multiple sclerosis, or MS, and amyotrophic lateral sclerosis, or ALS. In 2017, the Company expects to initiate Phase 2 clinical trials in the United States of FLX-787 in patients with motor neuron disease, primarily with ALS, and patients with Charcot-Marie-Tooth disease, or CMT. In 2016, the Company launched its consumer product, HOTSHOT®, to prevent and treat exercise-associated muscle cramps, or EAMCs. FLX-787, HOTSHOT and the Company's other product candidates are based on the potential mechanism of action we describe as Chemical Neuro Stimulation, which is the process by which a chemical signal, acting topically, induces a neuronal sensory signal that produces a beneficial effect. The Company's product candidates activate certain receptors in primary sensory neurons, which then act via neuronal circuits to reduce the repetitive firing, or hyperexcitability, of alpha-motor neurons in the spinal cord, thereby preventing or reducing the frequency and intensity of muscle cramps and spasms. In connection with the launch of HOTSHOT, the Company began operating as two reportable segments, Consumer Operations and Drug Development. See Note 15 for additional discussion and information on the Company's reportable segments. The Company is subject to risks common to companies in the biotechnology and consumer products industries, including, but not limited to, risks of failure of pre-clinical studies, clinical studies and clinical trials, the need to obtain marketing approval for its drug product candidates, the need to successfully commercialize and gain market acceptance of its drug product candidates and its consumer products, dependence on key personnel, protection of proprietary technology, compliance with government regulations and development by competitors of alternative products. In February 2015, the Company sold 5,491,191 shares of common stock (inclusive of 91,191 shares of common stock sold by the Company pursuant to the exercise of an overallotment option granted to the underwriters in connection with the offering) through an underwritten initial public offering ("IPO") at a price of $16.00 per share. The aggregate net proceeds received by the Company from the offering were approximately $79,900,000 , after deducting underwriting discounts and commissions and offering expenses payable by the Company of approximately $8,000,000 (See Note 2). Liquidity The Company has incurred an accumulated deficit of $76,645,613 from February 26, 2014 (inception) through December 31, 2016 , and will require substantial additional capital to fund its research and development and the growth of its consumer brand and HOTSHOT. The Company had cash, cash equivalents and marketable securities of $61,074,973 at December 31, 2016 . 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 successful commercialization of HOTSHOT and future consumer products, 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.

Summary of significant accounti

Summary of significant accounting policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of significant accounting policies	Summary of significant accounting policies Basis of presentation and use of estimates The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America ("GAAP"). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification ("ASC") and Accounting Standards Update ("ASU") of the Financial Accounting Standards Board ("FASB"). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company's management evaluates its estimates, which include, but are not limited to, estimates related to inventory write-offs, clinical study accruals, stock-based compensation expense, and amounts of expenses during the reported period. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions. Prior to the Company's IPO, the Company utilized significant estimates and assumptions in determining the fair value of its common stock. The Company utilized various valuation methodologies in accordance with the framework of the 2004 and 2013 American Institute of Certified Public Accountants Technical Practice Aids, Valuation of Privately-Held Company Equity Securities Issued as Compensation , to estimate the fair value of its common stock. Each valuation methodology included estimates and assumptions that required the Company's judgment. These estimates and assumptions included a number of objective and subjective factors, including external market conditions affecting the biotechnology industry sector, the prices at which the Company sold shares of preferred stock, the superior rights and preferences of securities senior to the Company's common stock at the time and the likelihood of achieving a liquidity event, such as an initial public offering or a sale of the Company. Significant changes to the key assumptions used in the valuations could have resulted in different fair values of common stock at each valuation date and may have materially affected the financial statements. Principles of consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries: TK Pharma, Inc., a Massachusetts Securities Corporation, and Flex Innovation Group LLC, a Delaware limited liability company, which contains the Company's consumer-related operations. All significant intercompany balances and transactions have been eliminated in consolidation. Concentration of risk The Company outsources the manufacture of HOTSHOT to a single co-packer that produces bottled finished goods. The Company also sources certain raw materials from sole suppliers. A disruption in the supply of materials or the production of finished goods could significantly impact the Company's revenues in the future as alternative sources of raw materials and co-packing may not be available at commercially reasonable rates or within a reasonably short period of time. Segment information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and assess performance. The Company and the Company's chief operating decision maker, the Company's Chief Executive Officer, view the Company's operations and manage its business as two operating segments, Drug Development and Consumer Operations (see Note 15). The Company operates in one geographic segment, the United States. Concentrations of credit risk and off-balance sheet risk Cash, cash equivalents and marketable securities are financial instruments that potentially subject the Company to concentrations of credit risk. The Company's cash, cash equivalents and marketable securities are held in accounts at financial institutions that management believes are creditworthy. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to any significant credit risk on these funds. The Company has no financial instruments with off-balance sheet risk of loss. Revenue Revenue is comprised of net product revenue and other revenue. Net product revenue includes sales of HOTSHOT finished goods to e-commerce customers, specialty retailers and sports teams. Other revenue consists of payments made by customers for expedited shipping and handling, which the Company began offering during the third quarter of 2016. Revenue is recognized when persuasive evidence of an arrangement exists, delivery of the product has occurred, the sales price is fixed or determinable and 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. Discounts provided to customers are accounted for as a reduction of net product revenue. 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, 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 collectibility is reasonably assured. Receivables are evaluated for collectibility 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, 2016 . Cost of product revenue Cost of product revenue includes the cost of raw materials utilized to produce HOTSHOT, co-packing fees, repacking fees, in-bound freight charges and warehouse and transportation costs incurred to bring HOTSHOT finished goods to salable condition. All other costs incurred after this condition is met are considered selling costs and included in selling, general and administrative expenses. Cost of product revenue also includes write-offs for inventory that has become obsolete, has a cost basis in excess of its estimated realizable value, or exceeds projected sales, as well as depreciation expense related to manufacturing equipment purchased to support production and royalty amounts payable to certain of the Company's founders on HOTSHOT sales. Inventory The Company launched HOTSHOT in the second quarter of 2016 and began capitalizing inventory costs associated with HOTSHOT in the first quarter of 2016, when it was determined that the inventory costs had probable future economic benefit. Inventory is stated at the lower of cost or estimated net realizable value, on a first-in, first-out ("FIFO") basis. The Company outsources the manufacture of HOTSHOT to a co-packer. Inventory at December 31, 2016 includes raw materials available for future production runs, as well as finished goods. The Company periodically analyzes its inventory levels and writes down inventory that has become obsolete, has a cost basis in excess of its estimated realizable value, or exceeds projected sales. Estimates of excess inventory consider factors such as inventory levels, production requirements, projected sales and the estimated shelf-lives of inventory components. Inventory write-offs are recorded as a component of cost of product revenue. Advertising expense Advertising expense consists of media and production costs related to print and digital advertising. All advertising is expensed as incurred. Total advertising expenses are included in selling, general and administrative and were approximately $2,936,000 for the year ended December 31, 2016 . There were no such costs in 2015 as the Company had not yet launched HOTSHOT. Shipping and handling costs Shipping and handling costs related to the movement of inventory to the Company's co-packer and from the co-packer to the Company's third-party warehousing partner is capitalized as inventory and expensed as a cost of product revenue when revenue is recognized. Shipping and handling costs to move finished goods from the Company's warehousing partner to the Company's third-party fulfillment partner or to customer locations are included in selling, general and administrative expense in the consolidated statement of operations, and were approximately $170,000 for the year ended December 31, 2016 . There were no such costs in 2015 as the Company had not yet launched HOTSHOT. Property and equipment Property and equipment is stated at cost, less accumulated depreciation. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed to operations as incurred, while costs of major additions and betterments are capitalized. Upon disposal, the related cost and accumulated depreciation is removed from the accounts and any resulting gain or loss is included in the results of operations. Depreciation is recorded, once assets are placed in service, using the straight-line method over the estimated useful lives of the respective assets, which are as follows: Asset type Estimated useful life Computers and computer equipment 3 years Laboratory equipment 3 years Manufacturing equipment 3 years Website development costs 1-2 years Impairment of long-lived assets The Company evaluates long-lived assets for potential impairment when events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Recoverability is measured by comparing the book values of the assets to the expected future net undiscounted cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the book value of the assets exceed their fair value. The Company has not recognized any impairment losses through December 31, 2016 . Research and development expense Research and development costs are charged to expense as incurred in performing research and development activities. The costs include employee compensation costs, clinical study costs, external consultant costs, regulatory costs and facilities and overhead costs. Facilities and overhead costs primarily include the allocation of insurance, rent, utility and office-related expenses attributable to research and development personnel. The Company records payments made to outside vendors in advance of services performed or goods being delivered for use in research and development activities as prepaid expenses, which are expensed as services are performed or goods are delivered. Stock-based compensation expense The Company accounts for its stock-based compensation awards to employees and directors in accordance with FASB ASC Topic 718, Compensation-Stock Compensation ("ASC 718"). ASC 718 requires all stock-based payments to employees, including grants of employee stock options, to be recognized in the statement of operations based on their grant date fair values. Compensation expense related to awards to employees with service conditions is recognized on a straight-line basis based on the grant date fair value over the associated service period of the award, which is generally the vesting term. Compensation expense related to awards to employees with performance conditions is recognized based on grant date fair value over the remaining service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the relative satisfaction of the performance conditions as of the reporting date. The Company accounts for stock-based compensation arrangements with non-employees based upon the fair value of the consideration received or the equity instruments issued, whichever is more reliably measurable, in accordance with the provisions of FASB ASC Topic 505-50, Equity-Based Payments to Non-Employees . The measurement date for non-employee awards is generally the date performance of services required from the non-employee is complete, resulting in periodic adjustments to stock-based compensation expense during the vesting period for changes in the fair value of the awards. Stock-based compensation costs for non-employee service awards are recognized as services are provided, which is generally the vesting period, on a straight-line basis. The unvested portion of the awards is subject to re-measurement over the vesting period. The Company estimates the fair value of its stock options using the Black-Scholes option pricing model, which requires the input of subjective assumptions, including (a) the expected stock price volatility, (b) the expected term of the award, (c) the risk-free interest rate, (d) expected dividends and (e) the estimated fair value of the Company's common stock on the measurement date. Due to the lack of significant trading history for the Company's common stock, it has based its estimate of expected volatility on the historical volatility of a group of similar companies that are publicly traded. When selecting these public companies on which it has based its expected stock price volatility, the Company selected companies with comparable characteristics, including enterprise value, risk profiles, position within the industry, and with historical share price information sufficient to meet the expected term of the stock-based awards. The Company computes historical volatility data using the volatility for the selected companies' shares during the equivalent period of the calculated expected term of the stock-based awards. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available. Due to the lack of Company specific historical option activity, the Company has estimated the expected term of its employee stock options using the "simplified" method, whereby, the expected term equals the arithmetic average of the vesting term and the original contractual term of the option. The expected term for non-employee awards is the remaining contractual term of the option. The risk-free interest rates are based on the U.S. Treasury securities with a maturity date commensurate with the expected term of the associated award. The Company has never paid, and does not expect to pay dividends in the foreseeable future. The Company is also required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from its estimates. The Company records stock-based compensation expense only for those awards that are expected to vest. To the extent that actual forfeitures differ from the Company's estimates, the differences are recorded as a cumulative adjustment in the period the estimates were revised. Income taxes Income taxes are recorded in accordance with FASB ASC Topic 740, Income Taxes ("ASC 740"), which provides for deferred taxes using an asset and liability approach. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial reporting and the tax reporting basis of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. The Company provides a valuation allowance against net deferred tax assets unless, based upon the available evidence, it is more likely than not that the deferred tax assets will be realized. The Company has evaluated available evidence and concluded that the Company may not realize the benefit of its deferred tax assets; therefore a valuation allowance has been established for the full amount of the deferred tax assets. The Company accounts for uncertain tax positions in accordance with the provisions of ASC 740. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. As of December 31, 2016 and December 31, 2015 , the Company did not have any significant uncertain tax positions. The Company's practice is to recognize interest and/or penalties related to income tax matters in income tax expense. Net loss per share attributable to common stockholders Basic net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and dilutive common stock equivalents outstanding for the period, determined using the treasury stock method and the if-converted method, for convertible securities, if inclusion of these is dilutive. For years ended December 31, 2016 and December 31, 2015 and the period from February 26, 2014 (inception) to December 31, 2014, the Company has excluded the effects of all potentially dilutive shares from the weighted-average number of common shares outstanding as their inclusion in the computation for each period would be anti-dilutive due to the net loss per share incurred by the Company. Comprehensive loss Comprehensive loss is the change in equity of a company during a period from transactions and other events and circumstances, excluding transactions resulting from investments by owners and distributions to owners. Comprehensive loss includes net loss and the change in accumulated other comprehensive loss for the period. Accumulated other comprehensive loss consisted entirely of unrealized gains and losses on available-for-sale marketable securities for the years ended December 31, 2016 and December 31, 2015. The Company's net loss equaled comprehensive loss for the period from February 26, 2014 to December 31, 2014. See the consolidated statements of comprehensive loss for relevant disclosures. The following tables summarize the changes in accumulated other comprehensive loss during the years ended December 31, 2016 and December 31, 2015. There was no accumulated other comprehensive loss for the period from February 26, 2014 to December 31, 2014: Balance as of December 31, 2015 $ (24,654 ) Other comprehensive gain 23,040 Balance as of December 31, 2016 $ (1,614 ) Balance as of December 31, 2014 $ — Other comprehensive loss (24,654 ) Balance as of December 31, 2015 $ (24,654 ) Recent accounting pronouncements In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The ASU provides for a single comprehensive model for use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance. The accounting standard was originally effective for interim and annual periods beginning after December 15, 2016 with no early adoption permitted. In July 2015, the FASB deferred the effective date of this accounting update to annual periods beginning after December 15, 2017, along with an option to permit early adoption as of the original effective date. The Company is required to adopt the amendments in the ASU using one of two acceptable methods: retrospectively to all prior reporting periods presented, with certain practical expedients permitted; or retrospectively with the cumulative effect of initially adopting the ASU recognized at the date of initial application. In March 2016, the FASB issued ASU 2016-08, Revenue from Contracts with Customers, Principal versus Agent Considerations (Reporting Revenue Gross versus Net), clarifying the implementation guidance on principal versus agent considerations. Specifically, an entity is required to determine whether the nature of a promise is to provide the specified good or service itself (that is, the entity is a principal) or to arrange for the good or service to be provided to the customer by the other party (that is, the entity is an agent). The determination influences the timing and amount of revenue recognition. The effective date and transition requirements for ASU 2016-08 are the same as the effective date and transition requirements for ASU 2014-09. The Company is currently evaluating the the adoption impact of the guidance related to the Company's sales of HOTSHOT. Based on evaluation of the Company's current revenue streams, the Company does not expect the new guidance to change the total amount of revenue recognized, but may accelerate the timing of when revenue is recognized. The Company expects that the guidance will impact the consolidated statement of operations and balance sheet, but cannot yet quantify those impacts at this time. The FASB has issued, and may issue in the future, interpretive guidance which may cause the Company's evaluation to change. Based on the Company's project plan and resources, it is following an appropriate timeline to allow for proper recognition, presentation and disclosure upon adoption effective the beginning of fiscal year 2018. In August 2014, the FASB issued ASU No. 2014-15 Presentation of Financial Statements - Going Concern (Subtopic 205-40). The ASU requires management of public and private companies to evaluate whether there is substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. Management’s evaluation should be based on relevant conditions and events that are known and reasonably knowable at the date that the financial statements are issued. If conditions or events raise substantial doubt about an entity’s ability to continue as a going concern, and substantial doubt is not alleviated after consideration of management’s plans, an entity should include a statement in the footnotes indicating that there is substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. The new standard is effective for annual periods ending after December 15, 2016, and for annual periods and interim periods thereafter. Early application was permitted. The Company adopted this standard as of December 31, 2016, and upon evaluation, has concluded that substantial doubt about the Company's ability to continue as a going concern does not exist through the relevant period. In July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330). This ASU simplifies the measurement of inventory by requiring certain inventory to be measured at the lower of cost or net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The amendments in this ASU are effective for fiscal years beginning after December 15, 2016 and for interim periods therein. Subsequent measurement is unchanged for inventory measured using LIFO or the retail inventory method. The Company is currently in the process of evaluating the impact of the guidance related to the launch of HOTSHOT. In February 2016, the FASB issued ASU No. 2016-02 Leases. The ASU requires lessees to recognize the assets and liabilities on their balance sheet for the rights and obligations created by most leases and continue to recognize expenses on their income statements over the lease term. It will also require disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. The guidance is effective for annual reporting periods beginning after December 15, 2018, and interim periods within those years. Early adoption is permitted for all entities. The Company is currently evaluating the impact of ASU 2016-02 on its consolidated financial statements and disclosures. In March 2016, the FASB issued ASU No. 2016-09 Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The ASU simplifies several aspects of the accounting for employee share-based payment transactions. The amendments in the update include income tax consequences related to excess tax benefits and tax deficiencies, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The guidance is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted for all entities in any interim or annual period. The Company does not believe that the impact of recording actual forfeitures as they occur, rather than estimating forfeitures by applying a forfeiture rate, will result in a significant impact to accumulated deficit upon recording the cumulative effect adjustment. In August 2016, the FASB issued ASU No. 2016-15 Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The update amends the guidance in ASU 230 Statement of Cash Flows, and clarifies how entities should classify certain cash receipts and cash payments on the statement of cash flows with the objective of reducing the existing diversity in practice related to eight specific cash flow issues. The amendments in this update are effective for annual periods beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company does not expect the adoption of ASU 2016-15 to have a material impact on its consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18 Statement of Cash Flows, which amends ASU Topic 230. This updates requires entities to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. As a result, entities will no longer be required to present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. When cash, cash equivalents, restricted cash and restricted cash equivalents are presented in more than one line item on the balance sheet, the new guidance requires a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheet. Entities will also have to disclose the nature of their restricted cash and restricted cash equivalent balances. The guidance is effective for fiscal years beginning after December 15, 2017 and interim periods within those years. Early adoption is permitted. Entities are required to apply the guidance retrospectively. The Company is currently evaluating the effect of adopting this new accounting guidance. 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 capital. Reverse stock split In January 2015, the Company effected a one-for- 4.2825 reverse stock split of its then issued and outstanding common stock. All share and per share amounts related to issued and outstanding common stock and outstanding options exercisable for common stock included in the Company's consolidated financial statements and notes to consolidated financial statements have been retroactively adjusted for all periods presented to reflect the reverse stock split, including reclassifying an amount equal to the reduction in par value of common stock to additional paid-in capital. The conversion ratios of the Company's convertible preferred stock have also been adjusted to reflect the reverse stock split. Subsequent events The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the consolidated financial statements for potential recognition or disclosure in the consolidated financial statements. Subsequent events have been evaluated through the date these consolidated financial statements were issued for potential recognition or disclosure in the consolidated financial statements (see Note 18).

Restricted cash

Restricted cash	12 Months Ended
	Dec. 31, 2016
Cash and Cash Equivalents [Abstract]
Restricted cash	Restricted cash As of December 31, 2016 and December 31, 2015 , the Company had $126,595 and $126,835 of restricted cash, respectively, 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	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair value measurements	Fair value measurements The Company records cash equivalents and marketable securities at fair value. ASC Topic 820 Fair Value Measurements and Disclosures established a fair value hierarchy for those instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). The hierarchy consists of three levels: Level 1 – Unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 – Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, directly or indirectly, for substantially the full term of the asset or liability. Level 3 – Unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability in which there is little, if any, market activity for the asset or liability at the measurement date. The following table summarizes the cash equivalents and marketable securities measured at fair value on a recurring basis as of December 31, 2016 and December 31, 2015 : Level 1 Level 2 Level 3 Balance as of December 31, 2016 Cash equivalents $ 11,681,074 $ — $ — $ 11,681,074 Marketable securities: Corporate debt securities — 1,518,240 — 1,518,240 Commercial paper — 6,081,202 — 6,081,202 U.S. government agency securities — 31,059,491 — 31,059,491 $ 11,681,074 $ 38,658,933 $ — $ 50,340,007 Level 1 Level 2 Level 3 Balance as of December 31, 2015 Cash equivalents $ 58,575,348 $ 1,410,322 $ — $ 59,985,670 Marketable securities: Corporate debt securities — 26,965,297 — 26,965,297 $ 58,575,348 $ 28,375,619 $ — $ 86,950,967 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, 2016 . After completing its validation procedures, the Company did not adjust or override any fair value carrying amounts of as of December 31, 2016 . 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, 2016 and 2015 , 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, 2016 . The Company had no financial assets or liabilities that were classified as Level 3 at any point during the year ended December 31, 2016 .

Cash equivalents and marketable

Cash equivalents and marketable securities	12 Months Ended
	Dec. 31, 2016
Cash and Cash Equivalents [Abstract]
Cash equivalents and marketable securities	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, 2016 and December 31, 2015 consisted of money market funds. Marketable securities as of December 31, 2016 consisted of corporate debt securities, commercial paper and U.S. government agency securities. Marketable securities as of December 31, 2015 consisted of corporate debt securities. Management determines the appropriate classification of the securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. The Company classifies its marketable securities as available-for-sale pursuant to ASC 320 Investments – Debt and Equity Securities . Marketable securities are recorded at fair value, with unrealized gains and losses included as a component of accumulated other comprehensive income (loss) in stockholders’ equity and a component of total comprehensive income (loss) in the consolidated statement of comprehensive income (loss), until realized. Realized gains and losses are included in investment income on a specific-identification basis. There were immaterial realized gains on marketable securities during the years ended December 31, 2016 and December 31, 2015 . 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, 2016 and December 31, 2015 consisted of the following: Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of December 31, 2016 Current (due within 1 year): Corporate debt securities $ 1,518,635 $ — $ (395 ) $ 1,518,240 Commercial paper 6,081,202 — — 6,081,202 U.S. government agency securities 31,060,710 2,912 (4,131 ) 31,059,491 Total $ 38,660,547 $ 2,912 $ (4,526 ) $ 38,658,933 Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of December 31, 2015 Current (due within 1 year): Corporate debt securities $ 24,666,607 $ 1,878 $ (16,137 ) $ 24,652,348 Noncurrent (due after 1 year through 5 years): Corporate debt securities 2,323,344 (10,395 ) 2,312,949 Total $ 26,989,951 $ 1,878 $ (26,532 ) $ 26,965,297 The Company held six and eleven securities that were in an unrealized loss position at December 31, 2016 and December 31, 2015 , respectively, 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 $16,519,620 and $ 24,967,915 at December 31, 2016 and December 31, 2015 , respectively. There were no individual securities that were in a significant unrealized loss position as of December 31, 2016 or December 31, 2015 . 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, 2016 .

Inventory

Inventory	12 Months Ended
	Dec. 31, 2016
Inventory Disclosure [Abstract]
Inventory	Inventory The Company began capitalizing inventory in the first quarter of 2016, when it was determined that the inventory had a probable future economic benefit. Inventory has been recorded at cost as of December 31, 2016 . Costs capitalized at December 31, 2016 relate to finished goods from the initial and second production runs of HOTSHOT, as well as raw materials available to be used for future production runs. The Company held no inventory at December 31, 2015. The following table presents inventory: December 31, 2016 December 31, 2015 Raw materials $ 19,888 $ — Finished goods 434,244 — Total inventory $ 454,132 $ — In the first quarter of 2016, the Company wrote off approximately $185,000 of materials purchased for the initial production run of HOTSHOT finished goods that, upon completion, were not expected to be sold based upon projected sales, estimated product shelf life, the number of units produced and production level requirements. The initial production run of HOTSHOT finished goods was completed in the second quarter of 2016, at which time the Company wrote off approximately $41,000 of production costs incurred for those finished goods that were not expected to be sold. During the third quarter of 2016, the Company wrote off approximately $33,000 of additional finished goods that were not expected to be sold based on shelf life requirements and the timing of Company's next production run, which took place during the fourth quarter of 2016. In the fourth quarter of 2016, upon completion of the second production run of HOTSHOT, the Company wrote off approximately $23,000 for certain raw materials that are not expected to be used in future production runs. Based on the Company's projected sales, estimated product shelf life and the number of units produced, the Company did not write off any finished goods produced during the second production run of HOTSHOT as they are expected to be sold during 2017. Write-offs totaled approximately $282,000 for the year ended December 31, 2016 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, 2016
Property, Plant and Equipment [Abstract]
Property and equipment, net	Property and equipment, net Property and equipment, net consists of the following: December 31, 2016 December 31, 2015 Computers and computer equipment $ 276,263 $ 177,240 Laboratory equipment 13,368 13,368 Manufacturing equipment 421,999 — Website development costs 159,836 — Capital in progress 7,863 251,893 Total property and equipment 879,329 442,501 Accumulated depreciation (323,014 ) (60,064 ) Property and equipment, net $ 556,315 $ 382,437 Capital in progress consists of assets acquired but not yet placed into service. At December 31, 2016 capital in progress consisted of computers and website development costs, and at December 31, 2015, capital in progress consisted primarily of manufacturing equipment. Depreciation expense was $277,231 , $49,881 and $11,997 for the years ended December 31, 2016 and December 31, 2015 and the period from February 26, 2014 (inception) to December 31, 2014, respectively.

Accrued expenses and other curr

Accrued expenses and other current liabilities	12 Months Ended
	Dec. 31, 2016
Payables and Accruals [Abstract]
Accrued expenses and other current liabilities	Accrued expenses and other current liabilities Accrued expenses and other current liabilities consist of the following: December 31, 2016 December 31, 2015 Payroll and employee-related costs $ 1,453,665 $ 1,299,248 Research and development costs 938,665 307,666 Professional fees 153,219 129,625 Consumer product-related costs 42,024 198,887 Other — 11,948 Total $ 2,587,573 $ 1,947,374

Commitments and contingencies

Commitments and contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	Commitments and contingencies Lease commitments On April 29, 2014, the Company leased office space in Boston, Massachusetts under an operating lease 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 (see Note 18). Additionally, on October 21, 2014, the Company leased office space in New York, New York under an operating lease that is scheduled to expire on October 31, 2018. As of December 31, 2016 , the minimum future lease payments under the Company's operating leases were as follows: 2017 $ 312,307 2018 122,570 Total minimum lease payments $ 434,877 The Boston lease agreement signed in January 2017 resulted in an aggregate increase to future minimum lease payments of $933,186 through 2019, that are not reflected in the table above. Rent expense is being recognized on a straight-line basis. The Company recorded approximately $337,000 and $253,000 of rent expense for the twelve months ended December 31, 2016 and December 31, 2015 , respectively, and $152,000 of rent expense for the period from February 26, 2014 (inception) to December 31, 2014. 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 $ 20,000 of royalty expense during the twelve months ended December 31, 2016. Royalty amounts owed to the founders as of December 31, 2016 were approximately $ 4,000 . No royalty amounts were owed to the founders as of December 31, 2015 or 2014. 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, 2016 .

Convertible preferred stock

Convertible preferred stock	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Convertible preferred stock	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, 2016 , 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, 2016 , 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, 2016 .

Common stock

Common stock	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Common stock	Common stock As of December 31, 2016 , 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 4,234,771 shares of restricted common stock outstanding as of December 31, 2016 . Unvested restricted common stock awards to non-employees are re-measured at each vest date and each financial reporting date. The following is a summary of restricted common stock activity: Number of Shares Weighted-Average Grant Date Fair Value Non-vested at December 31, 2015 2,202,262 $ 0.10 Issued — — Vested (1,016,304 ) 0.10 Forfeited — — Non-vested at December 31, 2016 1,185,958 $ 0.10 The total fair value of shares vested during the twelve months ended December 31, 2016 , the twelve months ended December 31, 2015 and the period from February 26, 2014 (inception) to December 31, 2014 was approximately $9,646,000 , $15,616,000 and $3,620,000 respectively. Restricted common stock to consultants During the twelve months ended December 31, 2016 , the Company issued 18,194 shares of restricted common stock to non-employee consultants and advisors. The Company has the right to repurchase any 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 $0.0001 per share. Such shares are not accounted for as outstanding until they vest. There were 7,360 shares of restricted common stock issued to consultants outstanding as of December 31, 2016 . Unvested restricted common stock awards to non-employees are re-measured at each vest date and each financial reporting date. The following is a summary of restricted common stock activity: Number of Shares Weighted-Average Grant Date Fair Value Non-vested at December 31, 2015 — $ — Issued 18,194 9.51 Vested (7,360 ) 9.19 Forfeited — — Non-vested at December 31, 2016 10,834 $ 9.72 The total fair value of shares vested during the twelve months ended December 31, 2016 was $71,000 . No shares were issued to consultants during the twelve months ended December 31, 2015 or the period from February 26, 2014 (inception) to December 31, 2014. 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, 2016 , 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, 2016 2015 Stock-based compensation awards 2,722,573 2,031,528 Vesting of restricted common stock 1,196,792 2,202,262 Employee stock purchase plan 354,569 175,131 Total 4,273,934 4,408,921

Stock-based compensation

Stock-based compensation	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based compensation	Stock-based compensation In March 2014, the Company adopted the Flex Pharma, Inc. 2014 Equity Incentive Plan (the "2014 Plan"), under which it had the ability to grant incentive stock options ("ISOs"), non-qualified stock options, restricted stock awards, restricted stock units and stock appreciation rights to purchase up to 116,754 shares of common stock. In April 2014, the Company amended the 2014 Plan to reserve for the issuance of up to 1,451,087 shares of common stock pursuant to equity awards. In September 2014, the Company further amended the 2014 Plan to reserve for the issuance of up to 2,070,200 shares of common stock pursuant to equity awards. Terms of stock award agreements, including vesting requirements, were determined by the board of directors, subject to the provisions of the 2014 Plan. For options granted under the 2014 Plan, the exercise price equaled the fair market value of the common stock as determined by the board of directors on the date of grant. No further awards will be granted under the 2014 Plan. In January 2015, the Company's board of directors adopted, and the Company's stockholders approved, the 2015 Equity Incentive Plan (the "2015 Plan"), which became effective immediately prior to the closing of the Company's IPO. The 2015 Plan provides for the grant of ISOs, nonstatutory stock options, restricted stock awards, restricted stock units, stock appreciation rights, performance-based stock awards and other stock-based awards. Additionally, the 2015 Plan provides for the grant of performance-based cash awards. ISOs may be granted only to the Company's employees. All other awards may be granted to the Company's employees, including officers, and to non-employee directors and consultants. As of December 31, 2016, there were 566,323 shares remaining available for the grant of stock awards under the 2015 Plan. During the period from February 26, 2014 (inception) to December 31, 2016 , the Company granted a total of 272,993 stock options to non-employee consultants and members of its Scientific Advisory Board, which are included in the following table. The options generally vest over a four -year period, and have a contractual term of ten years . The total stock-based compensation expense related to all non-employee stock options for the twelve months ended December 31, 2016 , the twelve months ended December 31, 2015 and the period from February 26, 2014 (inception) to December 31, 2014 was approximately $369,735 , $517,336 and $ 149,000 , respectively. The Company has awarded stock options to its employees, directors, advisors and consultants, pursuant to the plans described above. Stock options subsequent to the completion of the Company's IPO are granted with an exercise price equal to the closing market price of the Company's common stock on the date of grant. Stock options generally vest over one to four years and have a contractual term of ten years. Stock options are valued using the Black-Scholes option pricing model and compensation cost is recognized based on the resulting value over the service period. Unvested awards to non-employees are re-measured at each vest date and at each financial reporting date. The following table summarizes stock option activity for employees and non-employees for the twelve months ended December 31, 2016 : Shares Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at December 31, 2015 1,824,973 $ 8.34 8.90 $ 9,073,673 Granted 763,320 10.03 Exercised (8,516 ) 2.59 Cancelled or forfeited (423,527 ) 9.86 Outstanding at December 31, 2016 2,156,250 $ 8.66 7.94 $ 1,605,684 Exercisable at December 31, 2016 875,868 $ 7.49 6.87 $ 1,082,490 Vested or expected to vest at December 31, 2016 2,117,832 $ 8.64 7.92 $ 1,594,651 During 2016, 2015 and the period from February 26, 2014 (inception) to December 31, 2014, the Company granted stock options to purchase an aggregate of 763,320 , 994,748 , and 1,020,234 shares of its common stock, respectively. The weighted-average grant date fair value of option awards granted during 2016, 2015 and the period from February 26, 2014 (inception) to December 31, 2014 were $6.35 , $8.55 , and $2.20 , respectively. The number of stock options exercised during 2016, 2015 and the period from February 26, 2014 (inception) to December 31, 2014 were 8,516 , 47,280 , and 13,572 , respectively. The weighted-average exercise price of options exercised during 2016, 2015 and the period from February 26, 2014 (inception) to December 31, 2014 was $2.59 , $8.63 , and $0.60 , respectively. The total intrinsic value of options exercised during 2016, 2015 and the period from February 26, 2014 (inception) to December 31, 2014 was $64,302 , $149,386 , and $51,719 , respectively. The intrinsic value is calculated as the difference between the fair value of the Company's common stock and the exercise price of the options at the date of exercise. The Company estimates the fair value of each stock option award on the grant date using the Black-Scholes option-pricing model based on the following assumptions regarding the fair value of the underlying Common Stock on each measurement date: Year Ended December 31, 2016 Year Ended December 31, 2015 Period from Expected volatility 71.01% to 74.20% 72.98% to 74.94% 75.8% to 76.4% Risk-free interest rate 1.23% to 2.40% 1.62% to 2.49% 1.59% to 2.71% Expected term 5.3 - 10 years 5.3 - 10 years 6 - 10 years Expected dividend yield 0 % 0 % 0 % Total stock-based compensation expense recognized for employee and non-employee restricted common stock, and stock options granted to employees and non-employees is included in the Company's consolidated statements of operations and comprehensive loss as follows: Year Ended December 31, 2016 Year Ended December 31, 2015 Period from Research and development $ 2,435,565 $ 3,192,063 $ 648,001 Selling, general and administrative 4,137,398 3,405,296 814,060 Total $ 6,572,963 $ 6,597,359 $ 1,462,061 As of December 31, 2016 , there was approximately $8,668,326 of total unrecognized compensation cost related to unvested equity awards. Total unrecognized compensation cost will be adjusted for the re-measurement of non-employee awards as well as future changes in employee and non-employee forfeitures, if any. The Company expects to recognize that cost over a remaining weighted-average period of 2.11 years . In November 2015, the Company granted 150,000 performance-based stock options to an employee which would have vested upon the achievement of certain future revenue milestones. During the third quarter of 2016, these options were cancelled in conjunction with an employment termination agreement. The vesting conditions had not previously been considered probable, and no stock-based compensation expense was recorded related to this award. In May 2016, in connection with an amendment to an employment agreement, the Company recorded stock-based compensation expense for a modification to an option award that totaled approximately $227,000 . In August 2016, in connection with an employment termination agreement, the Company recorded stock-based compensation expense for a modification to an option award that totaled approximately $58,000 .

Income taxes

Income taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income taxes	Income taxes For the years ended December 31, 2016 and December 31, 2015 and for the period from February 26, 2014 (inception) to December 31, 2014, 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. The following table presents a reconciliation of income tax expense (benefit) computed at the statutory federal income tax rate to the effective income tax rate as reflected in the consolidated financial statements: Year Ended December 31, 2016 Year Ended December 31, 2015 Period from Federal income tax expense at statutory rate 35.0 % 35.0 % 35.0 % State income tax, net of federal benefit 5.0 % 3.4 % 3.7 % Permanent differences 0.0 % (0.2 )% (0.3 )% Stock-based compensation (2.6 )% (6.3 )% (5.3 )% Research credits 1.9 % 1.8 % 1.2 % Other, net (0.1 )% 0.4 % n/a Change in valuation allowance (39.2 )% (34.1 )% (34.3 )% 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, 2016 December 31, 2015 Deferred tax assets: U.S. and state net operating loss carryforwards $ 24,322,172 $ 11,118,289 Accruals and other temporary differences 529,462 510,897 Amortization 32,171 33,824 Stock-based compensation 1,847,441 473,801 Tax credit carryforward 1,423,292 671,012 Total deferred tax assets 28,154,538 12,807,823 Less valuation allowance (28,127,611 ) (12,688,401 ) Deferred tax assets 26,927 119,422 Deferred tax liabilities: Stock-based compensation (23,316 ) (110,366 ) Depreciation (3,611 ) (9,056 ) Accruals and other temporary differences — — Deferred tax liabilities (26,927 ) (119,422 ) Net deferred tax assets $ — $ — As of December 31, 2016 , the Company has U.S. federal net operating loss carryforwards of approximately $61,000,000 and U.S. state net operating loss carryforwards of approximately $58,500,000 ( $4,500,000 tax affected), which are available to reduce future taxable income. Approximately $120,000 of the federal and state net operating loss carryforwards will result in an increase to additional paid-in capital if and when these carryforwards are used to reduce federal and state income taxes payable. The Company also had federal research and development tax credit carryforwards of $1,200,000 and state research and development tax credit carryforwards of $340,000 , which may be used to offset future tax liabilities. The Company will adopt ASU 2016-09, Improvements to Employee Share-Based Payment Accounting , for the quarter ended March 31, 2017. As a result of adoption, the deferred tax assets associated net operating losses will increase by $120,000 . These amounts will be offset by a corresponding increase in the valuation allowance. The adoption of ASU 2016-09 will have not impact to the Company’s consolidated statement of operations, balance sheet, or retained earnings. The Company's federal and state operating loss carryforwards and tax credit carryforwards will expire at various dates through 2036 . 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 2016 deferred tax asset because it is more likely than not that the deferred tax asset will not be realized. The valuation allowance increased by $15,400,000 from December 31, 2015 to December 31, 2016, 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, 2016 and 2015, the Company had no accrued interest or penalties related to uncertain tax positions.

Net loss per share

Net loss per share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Net loss per share	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 method, for convertible securities, if inclusion of these is dilutive. 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 method, have been excluded from the computation of diluted weighted-average shares outstanding for the periods indicated, because including them would have had an anti-dilutive impact: Year Ended December 31, 2016 Year Ended December 31, 2015 Period from Series A Preferred Stock — — 15,775,221 Series B Preferred Stock — — 14,078,647 Options to purchase common stock 2,156,250 1,824,973 926,832 Unvested restricted common stock 1,196,792 2,202,262 3,218,590 Total 3,353,042 4,027,235 33,999,290

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment Information	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 and spasms 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, 2016 and December 31, 2015 , and for the period from February 26, 2014 (inception) to December 31, 2014 are as follows: Year Ended December 31, 2016 Consumer Operations Drug Development Corporate Consolidated Total revenue $ 1,010,663 — — $ 1,010,663 Loss from operations $ 10,023,137 19,620,338 10,242,757 $ 39,886,232 Interest income, net $ — — 393,109 $ 393,109 Year Ended December 31, 2015 Consumer Operations Drug Development Corporate Consolidated Total revenue $ — — — $ — Loss from operations $ 7,892,584 12,224,692 9,096,382 $ 29,213,658 Interest income, net $ — — 72,028 $ 72,028 Period from February 26, 2014 (Inception) to December 31, 2014 Consumer Operations Drug Development Corporate Consolidated Total revenue $ — — — $ — Loss from operations $ 898,504 4,003,911 3,127,391 $ 8,029,806 Interest income, net $ — — 18,946 $ 18,946

Related parties

Related parties	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Related parties	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 year ended December 31, 2016 totaled approximately $20,000 , including approximately $4,000 not yet paid as of year end. 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 is a Company controlled by the Company's Chief Executive Officer. In October 2015, the license agreement was assigned by ECLDS, LLC to a third party, that is not owned by the Company's 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 , and during the period from February 26, 2014 to December 31, 2014, the Company received approximately $32,000 , $61,000 , and $34,000 , 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, 2016
Quarterly Financial Information Disclosure [Abstract]
Quarterly financial information (unaudited)	Quarterly financial information (unaudited) First Quarter Ended March 31, 2016 Second Quarter Third Quarter Ended Fourth Quarter Ended December 31, 2016 Net product revenue $ — $ 112,685 $ 586,134 $ 291,099 Other revenue — — 12,940 7,805 Total revenue — 112,685 599,074 298,904 Costs and expenses: Cost of product revenue 197,020 110,931 221,090 133,706 Research and development 4,387,079 6,094,921 5,665,357 4,230,804 Selling, general and administrative 5,111,695 5,377,784 5,447,847 3,918,661 Total costs and expenses 9,695,794 11,583,636 11,334,294 8,283,171 Loss from operations (9,695,794 ) (11,470,951 ) (10,735,220 ) (7,984,267 ) Interest income, net 103,333 107,818 97,726 84,232 Net loss $ (9,592,461 ) $ (11,363,133 ) $ (10,637,494 ) $ (7,900,035 ) Net loss per share attributable to common stockholders — basic and diluted $ (0.61 ) $ (0.71 ) $ (0.65 ) $ (0.48 ) Weighted-average number of common shares outstanding — basic and diluted 15,843,532 16,105,555 16,361,617 16,619,596 First Quarter Ended March 31, 2015 Second Quarter Third Quarter Ended September 30, 2015 Fourth Quarter Ended December 31, 2015 Costs and expenses: Research and development $ 2,804,946 $ 3,190,178 $ 3,445,200 $ 3,309,055 Selling, general and administrative 3,216,212 3,904,403 4,722,281 4,621,383 Total costs and expenses 6,021,158 7,094,581 8,167,481 7,930,438 Loss from operations (6,021,158 ) (7,094,581 ) (8,167,481 ) (7,930,438 ) Interest income, net 3,577 16,183 14,637 37,631 Net loss $ (6,017,581 ) $ (7,078,398 ) $ (8,152,844 ) $ (7,892,807 ) Net loss per share attributable to common stockholders — basic and diluted $ (0.59 ) $ (0.47 ) $ (0.53 ) $ (0.51 ) Weighted-average number of common shares outstanding — basic and diluted 10,179,955 15,034,764 15,290,435 15,551,800

Subsequent events

Subsequent events	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent events	Subsequent events The Company has completed an evaluation of all subsequent events after the balance sheet date of December 31, 2016 through the date these consolidated financial statements were issued. The Company has concluded that no subsequent events have occurred that require disclosure, except as described below. Lease for the Company's headquarters On January 27, 2017, the Company entered into a lease agreement (the "Lease Agreement") with BP Prucenter Acquisition LLC for the Company's headquarters located at 800 Boylston Street, Boston, Massachusetts. The Company's current sublease will terminate on August 31, 2017, following which time the Company will lease the same location from September 1, 2017 until August 31, 2019 pursuant to the terms of the Lease Agreement. Under the Lease Agreement, the Company will lease 7,234 square feet which will result in an aggregate increase to future minimum lease payments of $933,186 through 2019. The Company's current security deposit amount, which totals $126,595 , will be unchanged upon commencement of the new lease.

Summary of significant accoun27

Summary of significant accounting policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Basis of presentation	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 inventory write-offs, clinical study accruals, stock-based compensation expense, and amounts of expenses during the reported period. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions. Prior to the Company's IPO, the Company utilized significant estimates and assumptions in determining the fair value of its common stock. The Company utilized various valuation methodologies in accordance with the framework of the 2004 and 2013 American Institute of Certified Public Accountants Technical Practice Aids, Valuation of Privately-Held Company Equity Securities Issued as Compensation , to estimate the fair value of its common stock. Each valuation methodology included estimates and assumptions that required the Company's judgment. These estimates and assumptions included a number of objective and subjective factors, including external market conditions affecting the biotechnology industry sector, the prices at which the Company sold shares of preferred stock, the superior rights and preferences of securities senior to the Company's common stock at the time and the likelihood of achieving a liquidity event, such as an initial public offering or a sale of the Company. Significant changes to the key assumptions used in the valuations could have resulted in different fair values of common stock at each valuation date and may have materially affected the financial statements.
Principles of consolidation	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, credit risk and off-balance sheet risk	Concentration of risk The Company outsources the manufacture of HOTSHOT to a single co-packer that produces bottled finished goods. The Company also sources certain raw materials from sole suppliers. A disruption in the supply of materials or the production of finished goods could significantly impact the Company's revenues in the future as alternative sources of raw materials and co-packing may not be available at commercially reasonable rates or within a reasonably short period of time. Concentrations of credit risk and off-balance sheet risk Cash, cash equivalents and marketable securities are financial instruments that potentially subject the Company to concentrations of credit risk. The Company's cash, cash equivalents and marketable securities are held in accounts at financial institutions that management believes are creditworthy. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to any significant credit risk on these funds. The Company has no financial instruments with off-balance sheet risk of loss.
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	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. Net product revenue and other revenue are presented net of taxes collected from customers and remitted to governmental authorities.
Revenue, Discounts	Discounts provided to customers are accounted for as a reduction of net product revenue.
Accounts receivable and allowance for doubtful accounts	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 collectibility is reasonably assured. Receivables are evaluated for collectibility 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 fees, repacking fees, in-bound freight charges and warehouse and transportation costs incurred to bring HOTSHOT finished goods to salable condition. All other costs incurred after this condition is met are considered selling costs and included in selling, general and administrative expenses. Cost of product revenue also includes write-offs for inventory that has become obsolete, has a cost basis in excess of its estimated realizable value, or exceeds projected sales, as well as depreciation expense related to manufacturing equipment purchased to support production and royalty amounts payable to certain of the Company's founders on HOTSHOT sales.
Inventory	Inventory The Company launched HOTSHOT in the second quarter of 2016 and began capitalizing inventory costs associated with HOTSHOT in the first quarter of 2016, when it was determined that the inventory costs had probable future economic benefit. Inventory is stated at the lower of cost or estimated net realizable value, on a first-in, first-out ("FIFO") basis. The Company outsources the manufacture of HOTSHOT to a co-packer. Inventory at December 31, 2016 includes raw materials available for future production runs, as well as finished goods. The Company periodically analyzes its inventory levels and writes down inventory that has become obsolete, has a cost basis in excess of its estimated realizable value, or exceeds projected sales. Estimates of excess inventory consider factors such as inventory levels, production requirements, projected sales and the estimated shelf-lives of inventory components. Inventory write-offs are recorded as a component of cost of product revenue.
Advertising expense	Advertising expense Advertising expense consists of media and production costs related to print and digital advertising. All advertising is expensed as incurred.
Shipping and handling costs	Shipping and handling costs Shipping and handling costs related to the movement of inventory to the Company's co-packer and from the co-packer to the Company's third-party warehousing partner is capitalized as inventory and expensed as a cost of product revenue when revenue is recognized. Shipping and handling costs to move finished goods from the Company's warehousing partner to the Company's third-party fulfillment partner or to customer locations are included in selling, general and administrative expense in the consolidated statement of operations
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 useful life Computers and computer equipment 3 years Laboratory equipment 3 years Manufacturing equipment 3 years Website development costs 1-2 years
Impairment of long-lived assets	Impairment of long-lived assets 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 expenses	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 ("ASC 718"). ASC 718 requires all stock-based payments to employees, including grants of employee stock options, to be recognized in the statement of operations based on their grant date fair values. Compensation expense related to awards to employees with service conditions is recognized on a straight-line basis based on the grant date fair value over the associated service period of the award, which is generally the vesting term. Compensation expense related to awards to employees with performance conditions is recognized based on grant date fair value over the remaining service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the relative satisfaction of the performance conditions as of the reporting date. The Company accounts for stock-based compensation arrangements with non-employees based upon the fair value of the consideration received or the equity instruments issued, whichever is more reliably measurable, in accordance with the provisions of FASB ASC Topic 505-50, Equity-Based Payments to Non-Employees . The measurement date for non-employee awards is generally the date performance of services required from the non-employee is complete, resulting in periodic adjustments to stock-based compensation expense during the vesting period for changes in the fair value of the awards. Stock-based compensation costs for non-employee service awards are recognized as services are provided, which is generally the vesting period, on a straight-line basis. The unvested portion of the awards is subject to re-measurement over the vesting period. The Company estimates the fair value of its stock options using the Black-Scholes option pricing model, which requires the input of subjective assumptions, including (a) the expected stock price volatility, (b) the expected term of the award, (c) the risk-free interest rate, (d) expected dividends and (e) the estimated fair value of the Company's common stock on the measurement date. Due to the lack of significant trading history for the Company's common stock, it has based its estimate of expected volatility on the historical volatility of a group of similar companies that are publicly traded. When selecting these public companies on which it has based its expected stock price volatility, the Company selected companies with comparable characteristics, including enterprise value, risk profiles, position within the industry, and with historical share price information sufficient to meet the expected term of the stock-based awards. The Company computes historical volatility data using the volatility for the selected companies' shares during the equivalent period of the calculated expected term of the stock-based awards. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available. Due to the lack of Company specific historical option activity, the Company has estimated the expected term of its employee stock options using the "simplified" method, whereby, the expected term equals the arithmetic average of the vesting term and the original contractual term of the option. The expected term for non-employee awards is the remaining contractual term of the option. The risk-free interest rates are based on the U.S. Treasury securities with a maturity date commensurate with the expected term of the associated award. The Company has never paid, and does not expect to pay dividends in the foreseeable future. The Company is also required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from its estimates. The Company records stock-based compensation expense only for those awards that are expected to vest. To the extent that actual forfeitures differ from the Company's estimates, the differences are recorded as a cumulative adjustment in the period the estimates were revised.
Income taxes	Income taxes Income taxes are recorded in accordance with FASB ASC Topic 740, Income Taxes ("ASC 740"), which provides for deferred taxes using an asset and liability approach. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial reporting and the tax reporting basis of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. The Company provides a valuation allowance against net deferred tax assets unless, based upon the available evidence, it is more likely than not that the deferred tax assets will be realized. The Company has evaluated available evidence and concluded that the Company may not realize the benefit of its deferred tax assets; therefore a valuation allowance has been established for the full amount of the deferred tax assets. The Company accounts for uncertain tax positions in accordance with the provisions of ASC 740. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. As of December 31, 2016 and December 31, 2015 , 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 method, for convertible securities, if inclusion of these is dilutive. For years ended December 31, 2016 and December 31, 2015 and the period from February 26, 2014 (inception) to December 31, 2014, 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 (Topic 606). The ASU provides for a single comprehensive model for use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance. The accounting standard was originally effective for interim and annual periods beginning after December 15, 2016 with no early adoption permitted. In July 2015, the FASB deferred the effective date of this accounting update to annual periods beginning after December 15, 2017, along with an option to permit early adoption as of the original effective date. The Company is required to adopt the amendments in the ASU using one of two acceptable methods: retrospectively to all prior reporting periods presented, with certain practical expedients permitted; or retrospectively with the cumulative effect of initially adopting the ASU recognized at the date of initial application. In March 2016, the FASB issued ASU 2016-08, Revenue from Contracts with Customers, Principal versus Agent Considerations (Reporting Revenue Gross versus Net), clarifying the implementation guidance on principal versus agent considerations. Specifically, an entity is required to determine whether the nature of a promise is to provide the specified good or service itself (that is, the entity is a principal) or to arrange for the good or service to be provided to the customer by the other party (that is, the entity is an agent). The determination influences the timing and amount of revenue recognition. The effective date and transition requirements for ASU 2016-08 are the same as the effective date and transition requirements for ASU 2014-09. The Company is currently evaluating the the adoption impact of the guidance related to the Company's sales of HOTSHOT. Based on evaluation of the Company's current revenue streams, the Company does not expect the new guidance to change the total amount of revenue recognized, but may accelerate the timing of when revenue is recognized. The Company expects that the guidance will impact the consolidated statement of operations and balance sheet, but cannot yet quantify those impacts at this time. The FASB has issued, and may issue in the future, interpretive guidance which may cause the Company's evaluation to change. Based on the Company's project plan and resources, it is following an appropriate timeline to allow for proper recognition, presentation and disclosure upon adoption effective the beginning of fiscal year 2018. In August 2014, the FASB issued ASU No. 2014-15 Presentation of Financial Statements - Going Concern (Subtopic 205-40). The ASU requires management of public and private companies to evaluate whether there is substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. Management’s evaluation should be based on relevant conditions and events that are known and reasonably knowable at the date that the financial statements are issued. If conditions or events raise substantial doubt about an entity’s ability to continue as a going concern, and substantial doubt is not alleviated after consideration of management’s plans, an entity should include a statement in the footnotes indicating that there is substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. The new standard is effective for annual periods ending after December 15, 2016, and for annual periods and interim periods thereafter. Early application was permitted. The Company adopted this standard as of December 31, 2016, and upon evaluation, has concluded that substantial doubt about the Company's ability to continue as a going concern does not exist through the relevant period. In July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330). This ASU simplifies the measurement of inventory by requiring certain inventory to be measured at the lower of cost or net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The amendments in this ASU are effective for fiscal years beginning after December 15, 2016 and for interim periods therein. Subsequent measurement is unchanged for inventory measured using LIFO or the retail inventory method. The Company is currently in the process of evaluating the impact of the guidance related to the launch of HOTSHOT. In February 2016, the FASB issued ASU No. 2016-02 Leases. The ASU requires lessees to recognize the assets and liabilities on their balance sheet for the rights and obligations created by most leases and continue to recognize expenses on their income statements over the lease term. It will also require disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. The guidance is effective for annual reporting periods beginning after December 15, 2018, and interim periods within those years. Early adoption is permitted for all entities. The Company is currently evaluating the impact of ASU 2016-02 on its consolidated financial statements and disclosures. In March 2016, the FASB issued ASU No. 2016-09 Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The ASU simplifies several aspects of the accounting for employee share-based payment transactions. The amendments in the update include income tax consequences related to excess tax benefits and tax deficiencies, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The guidance is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted for all entities in any interim or annual period. The Company does not believe that the impact of recording actual forfeitures as they occur, rather than estimating forfeitures by applying a forfeiture rate, will result in a significant impact to accumulated deficit upon recording the cumulative effect adjustment. In August 2016, the FASB issued ASU No. 2016-15 Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The update amends the guidance in ASU 230 Statement of Cash Flows, and clarifies how entities should classify certain cash receipts and cash payments on the statement of cash flows with the objective of reducing the existing diversity in practice related to eight specific cash flow issues. The amendments in this update are effective for annual periods beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company does not expect the adoption of ASU 2016-15 to have a material impact on its consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18 Statement of Cash Flows, which amends ASU Topic 230. This updates requires entities to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. As a result, entities will no longer be required to present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. When cash, cash equivalents, restricted cash and restricted cash equivalents are presented in more than one line item on the balance sheet, the new guidance requires a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheet. Entities will also have to disclose the nature of their restricted cash and restricted cash equivalent balances. The guidance is effective for fiscal years beginning after December 15, 2017 and interim periods within those years. Early adoption is permitted. Entities are required to apply the guidance retrospectively. The Company is currently evaluating the effect of adopting this new accounting guidance. 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	Fair value measurements The Company records cash equivalents and marketable securities at fair value. ASC Topic 820 Fair Value Measurements and Disclosures established a fair value hierarchy for those instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). The hierarchy consists of three levels: Level 1 – Unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 – Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, directly or indirectly, for substantially the full term of the asset or liability. Level 3 – Unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability in which there is little, if any, market activity for the asset or liability at the measurement date.

Summary of significant accoun28

Summary of significant accounting policies (Tables)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Depreciation over estimated useful life	Depreciation is recorded, once assets are placed in service, using the straight-line method over the estimated useful lives of the respective assets, which are as follows: Asset type Estimated useful life Computers and computer equipment 3 years Laboratory equipment 3 years Manufacturing equipment 3 years Website development costs 1-2 years Property and equipment, net consists of the following: December 31, 2016 December 31, 2015 Computers and computer equipment $ 276,263 $ 177,240 Laboratory equipment 13,368 13,368 Manufacturing equipment 421,999 — Website development costs 159,836 — Capital in progress 7,863 251,893 Total property and equipment 879,329 442,501 Accumulated depreciation (323,014 ) (60,064 ) Property and equipment, net $ 556,315 $ 382,437
Reclassification out of Accumulated Other Comprehensive Income	The following tables summarize the changes in accumulated other comprehensive loss during the years ended December 31, 2016 and December 31, 2015. There was no accumulated other comprehensive loss for the period from February 26, 2014 to December 31, 2014: Balance as of December 31, 2015 $ (24,654 ) Other comprehensive gain 23,040 Balance as of December 31, 2016 $ (1,614 )

Fair value measurements (Tables

Fair value measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Summary of Cash Equivalents and Marketable Securities Measured at Fair Value on a Recurring Basis	The following table summarizes the cash equivalents and marketable securities measured at fair value on a recurring basis as of December 31, 2016 and December 31, 2015 : Level 1 Level 2 Level 3 Balance as of December 31, 2016 Cash equivalents $ 11,681,074 $ — $ — $ 11,681,074 Marketable securities: Corporate debt securities — 1,518,240 — 1,518,240 Commercial paper — 6,081,202 — 6,081,202 U.S. government agency securities — 31,059,491 — 31,059,491 $ 11,681,074 $ 38,658,933 $ — $ 50,340,007 Level 1 Level 2 Level 3 Balance as of December 31, 2015 Cash equivalents $ 58,575,348 $ 1,410,322 $ — $ 59,985,670 Marketable securities: Corporate debt securities — 26,965,297 — 26,965,297 $ 58,575,348 $ 28,375,619 $ — $ 86,950,967

Cash equivalents and marketab30

Cash equivalents and marketable securities (Tables)	12 Months Ended
	Dec. 31, 2016
Cash and Cash Equivalents [Abstract]
Schedule of Marketable Securities	Marketable securities at December 31, 2016 and December 31, 2015 consisted of the following: Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of December 31, 2016 Current (due within 1 year): Corporate debt securities $ 1,518,635 $ — $ (395 ) $ 1,518,240 Commercial paper 6,081,202 — — 6,081,202 U.S. government agency securities 31,060,710 2,912 (4,131 ) 31,059,491 Total $ 38,660,547 $ 2,912 $ (4,526 ) $ 38,658,933 Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of December 31, 2015 Current (due within 1 year): Corporate debt securities $ 24,666,607 $ 1,878 $ (16,137 ) $ 24,652,348 Noncurrent (due after 1 year through 5 years): Corporate debt securities 2,323,344 (10,395 ) 2,312,949 Total $ 26,989,951 $ 1,878 $ (26,532 ) $ 26,965,297

Inventory (Tables)

Inventory (Tables)	12 Months Ended
	Dec. 31, 2016
Inventory Disclosure [Abstract]
Schedule of Inventory, Net	The following table presents inventory: December 31, 2016 December 31, 2015 Raw materials $ 19,888 $ — Finished goods 434,244 — Total inventory $ 454,132 $ —

Property and equipment, net (Ta

Property and equipment, net (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Property and equipment, net	Depreciation is recorded, once assets are placed in service, using the straight-line method over the estimated useful lives of the respective assets, which are as follows: Asset type Estimated useful life Computers and computer equipment 3 years Laboratory equipment 3 years Manufacturing equipment 3 years Website development costs 1-2 years Property and equipment, net consists of the following: December 31, 2016 December 31, 2015 Computers and computer equipment $ 276,263 $ 177,240 Laboratory equipment 13,368 13,368 Manufacturing equipment 421,999 — Website development costs 159,836 — Capital in progress 7,863 251,893 Total property and equipment 879,329 442,501 Accumulated depreciation (323,014 ) (60,064 ) Property and equipment, net $ 556,315 $ 382,437

Accrued expenses and other cu33

Accrued expenses and other current liabilities (Tables)	12 Months Ended
	Dec. 31, 2016
Payables and Accruals [Abstract]
Accrued expenses	Accrued expenses and other current liabilities consist of the following: December 31, 2016 December 31, 2015 Payroll and employee-related costs $ 1,453,665 $ 1,299,248 Research and development costs 938,665 307,666 Professional fees 153,219 129,625 Consumer product-related costs 42,024 198,887 Other — 11,948 Total $ 2,587,573 $ 1,947,374
Other current liabilities	Accrued expenses and other current liabilities consist of the following: December 31, 2016 December 31, 2015 Payroll and employee-related costs $ 1,453,665 $ 1,299,248 Research and development costs 938,665 307,666 Professional fees 153,219 129,625 Consumer product-related costs 42,024 198,887 Other — 11,948 Total $ 2,587,573 $ 1,947,374

Commitments and contingencies (

Commitments and contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Minimum future lease payments	As of December 31, 2016 , the minimum future lease payments under the Company's operating leases were as follows: 2017 $ 312,307 2018 122,570 Total minimum lease payments $ 434,877

Common stock (Tables)

Common stock (Tables)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Restricted common stock activity	The following is a summary of restricted common stock activity: Number of Shares Weighted-Average Grant Date Fair Value Non-vested at December 31, 2015 2,202,262 $ 0.10 Issued — — Vested (1,016,304 ) 0.10 Forfeited — — Non-vested at December 31, 2016 1,185,958 $ 0.10
Shares reserved for future issuance	The Company has reserved the following number of shares of common stock for future issuance: As of December 31, 2016 2015 Stock-based compensation awards 2,722,573 2,031,528 Vesting of restricted common stock 1,196,792 2,202,262 Employee stock purchase plan 354,569 175,131 Total 4,273,934 4,408,921

Stock-based compensation (Table

Stock-based compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of stock option activity	The following table summarizes stock option activity for employees and non-employees for the twelve months ended December 31, 2016 : Shares Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at December 31, 2015 1,824,973 $ 8.34 8.90 $ 9,073,673 Granted 763,320 10.03 Exercised (8,516 ) 2.59 Cancelled or forfeited (423,527 ) 9.86 Outstanding at December 31, 2016 2,156,250 $ 8.66 7.94 $ 1,605,684 Exercisable at December 31, 2016 875,868 $ 7.49 6.87 $ 1,082,490 Vested or expected to vest at December 31, 2016 2,117,832 $ 8.64 7.92 $ 1,594,651
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 December 31, 2016 Year Ended December 31, 2015 Period from Expected volatility 71.01% to 74.20% 72.98% to 74.94% 75.8% to 76.4% Risk-free interest rate 1.23% to 2.40% 1.62% to 2.49% 1.59% to 2.71% Expected term 5.3 - 10 years 5.3 - 10 years 6 - 10 years Expected dividend yield 0 % 0 % 0 %
Summary of stock-based compensation expense	Total stock-based compensation expense recognized for employee and non-employee restricted common stock, and stock options granted to employees and non-employees is included in the Company's consolidated statements of operations and comprehensive loss as follows: Year Ended December 31, 2016 Year Ended December 31, 2015 Period from Research and development $ 2,435,565 $ 3,192,063 $ 648,001 Selling, general and administrative 4,137,398 3,405,296 814,060 Total $ 6,572,963 $ 6,597,359 $ 1,462,061

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016 Year Ended December 31, 2015 Period from Federal income tax expense at statutory rate 35.0 % 35.0 % 35.0 % State income tax, net of federal benefit 5.0 % 3.4 % 3.7 % Permanent differences 0.0 % (0.2 )% (0.3 )% Stock-based compensation (2.6 )% (6.3 )% (5.3 )% Research credits 1.9 % 1.8 % 1.2 % Other, net (0.1 )% 0.4 % n/a Change in valuation allowance (39.2 )% (34.1 )% (34.3 )% 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, 2016 December 31, 2015 Deferred tax assets: U.S. and state net operating loss carryforwards $ 24,322,172 $ 11,118,289 Accruals and other temporary differences 529,462 510,897 Amortization 32,171 33,824 Stock-based compensation 1,847,441 473,801 Tax credit carryforward 1,423,292 671,012 Total deferred tax assets 28,154,538 12,807,823 Less valuation allowance (28,127,611 ) (12,688,401 ) Deferred tax assets 26,927 119,422 Deferred tax liabilities: Stock-based compensation (23,316 ) (110,366 ) Depreciation (3,611 ) (9,056 ) Accruals and other temporary differences — — Deferred tax liabilities (26,927 ) (119,422 ) Net deferred tax assets $ — $ —

Net loss per share (Tables)

Net loss per share (Tables)	12 Months Ended
	Dec. 31, 2016
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 method, have been excluded from the computation of diluted weighted-average shares outstanding for the periods indicated, because including them would have had an anti-dilutive impact: Year Ended December 31, 2016 Year Ended December 31, 2015 Period from Series A Preferred Stock — — 15,775,221 Series B Preferred Stock — — 14,078,647 Options to purchase common stock 2,156,250 1,824,973 926,832 Unvested restricted common stock 1,196,792 2,202,262 3,218,590 Total 3,353,042 4,027,235 33,999,290

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Schedule of Segment Reporting Information	Information for the Company's reportable segments for the years ended December 31, 2016 and December 31, 2015 , and for the period from February 26, 2014 (inception) to December 31, 2014 are as follows: Year Ended December 31, 2016 Consumer Operations Drug Development Corporate Consolidated Total revenue $ 1,010,663 — — $ 1,010,663 Loss from operations $ 10,023,137 19,620,338 10,242,757 $ 39,886,232 Interest income, net $ — — 393,109 $ 393,109 Year Ended December 31, 2015 Consumer Operations Drug Development Corporate Consolidated Total revenue $ — — — $ — Loss from operations $ 7,892,584 12,224,692 9,096,382 $ 29,213,658 Interest income, net $ — — 72,028 $ 72,028 Period from February 26, 2014 (Inception) to December 31, 2014 Consumer Operations Drug Development Corporate Consolidated Total revenue $ — — — $ — Loss from operations $ 898,504 4,003,911 3,127,391 $ 8,029,806 Interest income, net $ — — 18,946 $ 18,946

Quarterly financial informati40

Quarterly financial information (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly financial information	First Quarter Ended March 31, 2016 Second Quarter Third Quarter Ended Fourth Quarter Ended December 31, 2016 Net product revenue $ — $ 112,685 $ 586,134 $ 291,099 Other revenue — — 12,940 7,805 Total revenue — 112,685 599,074 298,904 Costs and expenses: Cost of product revenue 197,020 110,931 221,090 133,706 Research and development 4,387,079 6,094,921 5,665,357 4,230,804 Selling, general and administrative 5,111,695 5,377,784 5,447,847 3,918,661 Total costs and expenses 9,695,794 11,583,636 11,334,294 8,283,171 Loss from operations (9,695,794 ) (11,470,951 ) (10,735,220 ) (7,984,267 ) Interest income, net 103,333 107,818 97,726 84,232 Net loss $ (9,592,461 ) $ (11,363,133 ) $ (10,637,494 ) $ (7,900,035 ) Net loss per share attributable to common stockholders — basic and diluted $ (0.61 ) $ (0.71 ) $ (0.65 ) $ (0.48 ) Weighted-average number of common shares outstanding — basic and diluted 15,843,532 16,105,555 16,361,617 16,619,596 First Quarter Ended March 31, 2015 Second Quarter Third Quarter Ended September 30, 2015 Fourth Quarter Ended December 31, 2015 Costs and expenses: Research and development $ 2,804,946 $ 3,190,178 $ 3,445,200 $ 3,309,055 Selling, general and administrative 3,216,212 3,904,403 4,722,281 4,621,383 Total costs and expenses 6,021,158 7,094,581 8,167,481 7,930,438 Loss from operations (6,021,158 ) (7,094,581 ) (8,167,481 ) (7,930,438 ) Interest income, net 3,577 16,183 14,637 37,631 Net loss $ (6,017,581 ) $ (7,078,398 ) $ (8,152,844 ) $ (7,892,807 ) Net loss per share attributable to common stockholders — basic and diluted $ (0.59 ) $ (0.47 ) $ (0.53 ) $ (0.51 ) Weighted-average number of common shares outstanding — basic and diluted 10,179,955 15,034,764 15,290,435 15,551,800

Organization and operations (De

Organization and operations (Details)	Feb. 03, 2015USD ($)$ / sharesshares	Feb. 28, 2015USD ($)$ / sharesshares	Sep. 30, 2016segment	Dec. 31, 2014USD ($)	Dec. 31, 2016USD ($)segment	Dec. 31, 2015USD ($)
Subsidiary, Sale of Stock [Line Items]
Number of reportable segments | segment			2		2
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
Accumulated deficit					76,645,613	$ 37,152,490
Cash, cash equivalents, and marketable securities					$ 61,074,973
IPO
Subsidiary, Sale of Stock [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
Subsidiary, Sale of Stock [Line Items]
Common stock, shares issued | shares	91,191	91,191

Summary of significant accoun42

Summary of significant accounting policies - Narrative (Details)	Feb. 03, 2015USD ($)$ / sharesshares	Feb. 28, 2015USD ($)$ / sharesshares	Jan. 31, 2015	Dec. 31, 2016shares	Sep. 30, 2016	Dec. 31, 2014USD ($)	Dec. 31, 2016USD ($)segmentshares	Dec. 31, 2015USD ($)shares
Entity Location [Line Items]
Number of operating segments | segment							2
Revenue recognition, refund period				30 days	21 days
Shipping and handling costs							$ 170,000	$ 0
Advertising expenses							2,936,000	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 (in shares) | shares	6,971,108
Common stock, shares authorized (shares) | shares				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
IPO
Entity Location [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
Entity Location [Line Items]
Common stock, shares issued | shares	91,191	91,191
United States
Entity Location [Line Items]
Number of geographic segments | segment							1

Summary of significant accoun43

Summary of significant accounting policies - Depreciation Over Estimated Useful Life (Details)	12 Months Ended
	Dec. 31, 2016
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 | Website development costs
Property, Plant and Equipment [Line Items]
Estimated useful life	1 year
Maximum | Website development costs
Property, Plant and Equipment [Line Items]
Estimated useful life	2 years

Summary of significant accoun44

Summary of significant accounting policies - Summary of changes in accumulated other comprehensive loss (Details) - USD ($)	10 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Loss, beginning balance		$ (24,654)	$ 0
Other comprehensive gain	$ 0	23,040	(24,654)
Accumulated Other Comprehensive Loss, ending balance	$ 0	$ (1,614)	$ (24,654)

Restricted cash (Details)

Restricted cash (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 126,595	$ 126,835
Letter of Credit
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 126,595	$ 126,835

Fair value measurements (Detail

Fair value measurements (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Marketable securities:
Marketable securities	$ 38,658,933	$ 26,965,297
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	11,681,074	59,985,670
Marketable securities:
Total assets	50,340,007	86,950,967
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	11,681,074	58,575,348
Marketable securities:
Total assets	11,681,074	58,575,348
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		1,410,322
Marketable securities:
Total assets	38,658,933	28,375,619
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0
Marketable securities:
Total assets	0	0
Fair Value, Measurements, Recurring | Corporate debt securities
Marketable securities:
Marketable securities	1,518,240	26,965,297
Fair Value, Measurements, Recurring | Corporate debt securities | Level 1
Marketable securities:
Marketable securities	0	0
Fair Value, Measurements, Recurring | Corporate debt securities | Level 2
Marketable securities:
Marketable securities	1,518,240	26,965,297
Fair Value, Measurements, Recurring | Corporate debt securities | Level 3
Marketable securities:
Marketable securities	0	$ 0
Fair Value, Measurements, Recurring | Commercial paper
Marketable securities:
Marketable securities	6,081,202
Fair Value, Measurements, Recurring | Commercial paper | Level 1
Marketable securities:
Marketable securities	0
Fair Value, Measurements, Recurring | Commercial paper | Level 2
Marketable securities:
Marketable securities	6,081,202
Fair Value, Measurements, Recurring | Commercial paper | Level 3
Marketable securities:
Marketable securities	0
Fair Value, Measurements, Recurring | U.S. government agency securities
Marketable securities:
Marketable securities	31,059,491
Fair Value, Measurements, Recurring | U.S. government agency securities | Level 1
Marketable securities:
Marketable securities	0
Fair Value, Measurements, Recurring | U.S. government agency securities | Level 2
Marketable securities:
Marketable securities	31,059,491
Fair Value, Measurements, Recurring | U.S. government agency securities | Level 3
Marketable securities:
Marketable securities	$ 0

Cash equivalents and marketab47

Cash equivalents and marketable securities (Details)	Dec. 31, 2016USD ($)security	Dec. 31, 2015USD ($)security
Marketable securities:
Amortized Cost	$ 38,660,547	$ 26,989,951
Unrealized Gains	2,912	1,878
Unrealized Losses	(4,526)	(26,532)
Fair Value	$ 38,658,933	$ 26,965,297
Number of debt securities held | security	6	11
Aggregate fair value of debt securities in an unrealized loss position	$ 16,519,620	$ 24,967,915
Current Assets | Corporate debt securities
Marketable securities:
Amortized Cost	1,518,635	24,666,607
Unrealized Gains	0	1,878
Unrealized Losses	(395)	(16,137)
Fair Value	1,518,240	24,652,348
Current Assets | Commercial paper
Marketable securities:
Amortized Cost	6,081,202
Unrealized Gains	0
Unrealized Losses	0
Fair Value	6,081,202
Current Assets | U.S. government agency securities
Marketable securities:
Amortized Cost	31,060,710
Unrealized Gains	2,912
Unrealized Losses	(4,131)
Fair Value	$ 31,059,491
Noncurrent Assets | Corporate debt securities
Marketable securities:
Amortized Cost		2,323,344
Unrealized Losses		(10,395)
Fair Value		$ 2,312,949

Inventory (Details)

Inventory (Details) - USD ($)	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Raw materials	$ 19,888				$ 19,888	$ 0
Finished goods	434,244				434,244	0
Total inventory	454,132				454,132	$ 0
Write-off of inventory	$ 23,000	$ 33,000	$ 41,000	$ 185,000	$ 282,000

Property and equipment, net (De

Property and equipment, net (Details) - USD ($)	10 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Total property and equipment		$ 879,329	$ 442,501
Accumulated depreciation		(323,014)	(60,064)
Property and equipment, net		556,315	382,437
Depreciation expense	$ 11,997	277,231	49,881
Computers and computer equipment
Property, Plant and Equipment [Line Items]
Total property and equipment		276,263	177,240
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment		13,368	13,368
Manufacturing equipment
Property, Plant and Equipment [Line Items]
Total property and equipment		421,999	0
Website development costs
Property, Plant and Equipment [Line Items]
Total property and equipment		159,836	0
Capital in progress
Property, Plant and Equipment [Line Items]
Total property and equipment		$ 7,863	$ 251,893

Accrued expenses and other cu50

Accrued expenses and other current liabilities (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Payroll and employee-related costs	$ 1,453,665	$ 1,299,248
Research and development costs	938,665	307,666
Professional fees	153,219	129,625
Consumer product-related costs	42,024	198,887
Other	0	11,948
Total	$ 2,587,573	$ 1,947,374

Commitments and contingencies -

Commitments and contingencies - Minimum future lease payments (Details)	Dec. 31, 2016USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,016	$ 312,307
2,017	122,570
Total minimum lease payments	$ 434,877

Commitments and contingencies52

Commitments and contingencies - Narrative (Details) - USD ($)	Jan. 27, 2017	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Long-term Purchase Commitment [Line Items]
Rent expense			$ 152,000	$ 337,000	$ 253,000
Percent of gross sales due to related parties		2.00%				2.00%
Royalty expense				20,000	0
Royalties payable			$ 0	$ 4,000	$ 0	$ 0
Subsequent Event | 800 Boylston St
Long-term Purchase Commitment [Line Items]
Operating leases, increase in future minimum payments due	$ 933,186

Convertible preferred stock - N

Convertible preferred stock - Narrative (Details) - USD ($)	3 Months Ended	4 Months Ended	10 Months Ended	12 Months Ended
	May 31, 2014	Oct. 31, 2014	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Preferred stock, authorized (shares)				10,000,000	10,000,000
Preferred stock, par value (in usd per share)				$ 0.0001	$ 0.0001
Preferred stock, carrying value				$ 0	$ 0
Series A convertible preferred stock
Class of Stock [Line Items]
Preferred stock, authorized (shares)			16,000,000	0
Preferred stock, par value (in usd per share)			$ 0.0001
Issuance of stock/IPO proceeds, net of issuance costs (in shares)	15,775,221
Convertible preferred stock, automatic conversion, minimum share price (in usd per share)	$ 1
Net proceeds from issuance of convertible preferred stock	$ 15,637,032		$ 15,581,811	$ 0	0
Preferred stock, carrying value					15,637,032
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, authorized (shares)			14,500,000	0
Preferred stock, par value (in usd per share)			$ 0.0001
Issuance of stock/IPO proceeds, net of issuance costs (in shares)		14,078,647
Convertible preferred stock, automatic conversion, minimum share price (in usd per share)		$ 1.81
Net proceeds from issuance of convertible preferred stock		$ 25,394,135	$ 25,394,135	$ 0	0
Preferred stock, carrying value					$ 25,394,135

Common stock - Narrative (Detai

Common stock - Narrative (Details) - USD ($)	1 Months Ended		10 Months Ended	12 Months Ended
	Apr. 30, 2014	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Common stock, shares authorized (shares)				100,000,000	100,000,000
Common stock, par value (in usd per share)				$ 0.0001	$ 0.0001
Proceeds from sale of restricted common stock to founders			$ 2,321	$ 0	$ 0
Stock issued under Employee Stock Purchase Plan				0
Unvested restricted common stock
Class of Stock [Line Items]
Restricted common stock, shares sold	867,314	4,553,415
Restricted common stock, price per share (in usd per share)		$ 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				$ 0.0004
Restricted common stock, shares outstanding				4,234,771
Restricted common stock, fair value of shares vested			$ 3,620,000	$ 9,646,000	$ 15,616,000
Issued, number of shares				0
Unvested restricted common stock | Vests upon issuance
Class of Stock [Line Items]
Restricted common stock, percent vested				25.00%
Unvested restricted common stock | Vests ratably over four years
Class of Stock [Line Items]
Restricted common stock, percent vested				75.00%
Restricted common stock, vesting period				4 years
Non-employee Consultants and Advisers | Unvested restricted common stock
Class of Stock [Line Items]
Restricted common stock, repurchase period				90 days
Restricted common stock, repurchase price				$ 0.0001
Restricted common stock, shares outstanding				7,360
Restricted common stock, fair value of shares vested				$ 71,000
Issued, number of shares			0	18,194	0

Common stock - Restricted commo

Common stock - Restricted common stock activity (Details) - Unvested restricted common stock - $ / shares	10 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance, non-vested, number of shares		2,202,262
Issued, number of shares		0
Vested, number of shares		(1,016,304)
Forfeited, number of shares		0
Ending balance, non-vested, number of shares		1,185,958	2,202,262
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning balance, non-vested, weighted average grant date fair value (in usd per share)		$ 0.10
Issued, weighted average grant date fair value (in usd per share)		0
Vested, weighted average grant date fair value (in usd per share)		0.10
Forfeited, weighted average grant date fair value (in usd per share)		0
Ending balance, non-vested, weighted average grant date fair value (in usd per share)		$ 0.10	$ 0.10
Non-employee Consultants and Advisers
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance, non-vested, number of shares		0
Issued, number of shares	0	18,194	0
Vested, number of shares		(7,360)
Forfeited, number of shares		0
Ending balance, non-vested, number of shares		10,834	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning balance, non-vested, weighted average grant date fair value (in usd per share)		$ 0
Issued, weighted average grant date fair value (in usd per share)		9.51
Vested, weighted average grant date fair value (in usd per share)		9.19
Forfeited, weighted average grant date fair value (in usd per share)		0
Ending balance, non-vested, weighted average grant date fair value (in usd per share)		$ 9.72	$ 0

Common stock - Shares reserved

Common stock - Shares reserved for future issuance (Details) - shares	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Stock-based compensation awards	2,722,573	2,031,528
Employee stock purchase plan	354,569	175,131
Total	4,273,934	4,408,921
Unvested restricted common stock
Class of Stock [Line Items]
Vesting of restricted common stock	1,196,792	2,202,262

Stock-based compensation - Narr

Stock-based compensation - Narrative (Details) - USD ($)	1 Months Ended			10 Months Ended	12 Months Ended		34 Months Ended
	Aug. 31, 2016	May 31, 2016	Nov. 30, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Sep. 30, 2014	Apr. 30, 2014	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense				$ 1,462,061	$ 6,572,963	$ 6,597,359
Shares granted				1,020,234	763,320	994,748
Shares granted, weighted-average grant date fair value (in usd per share)				$ 2.20	$ 6.35	$ 8.55
Shares exercised				13,572	8,516	47,280
Shares exercised, weighted average exercise price (in usd per share)				$ 0.60	$ 2.59	$ 8.63
Stock options exercised, intrinsic value				$ 51,719	$ 64,302	$ 149,386
Unrecognized compensation cost					$ 8,668,326		$ 8,668,326
Unrecognized compensation cost, recognition period					2 years 1 month 10 days
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							272,993
Stock options, vesting period							4 years
Stock options, contractual term							10 years
Stock-based compensation expense				$ 149,000	$ 369,735	$ 517,336
Options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, contractual term					10 years
Stock-based compensation expense	$ 58,000	$ 227,000
Options to purchase common stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period					1 year
Options to purchase common stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period					4 years
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			150,000
Flex Pharma, Inc. 2014 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized								2,070,200	1,451,087	116,754
Shares remaining available for grant of stock awards					566,323		566,323

Stock-based compensation - Summ

Stock-based compensation - Summary of stock option activity (Details) - USD ($)	10 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Shares
Shares outstanding, beginning balance		1,824,973
Shares granted	1,020,234	763,320	994,748
Shares exercised	(13,572)	(8,516)	(47,280)
Shares canceled or forfeited		(423,527)
Shares outstanding, ending balance		2,156,250	1,824,973
Shares exercisable		875,868
Shares vested or expected to vest		2,117,832
Weighted-Average Exercise Price
Shares outstanding, beginning balance, weighted average exercise price (in usd per share)		$ 8.34
Shares granted, weighted average exercise price (in usd per share)		10.03
Shares exercised, weighted average exercise price (in usd per share)	$ 0.60	2.59	$ 8.63
Shares canceled or forfeited, weighted average exercise price (in usd per share)		9.86
Shares outstanding, ending balance, weighted average exercise price (in usd per share)		8.66	$ 8.34
Shares exercisable, weighted average exercise price (in usd per share)		7.49
Shares vested or expected to vest, weighted average exercise price (in usd per share)		$ 8.64
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, weighted average remaining contractual term		7 years 11 months 9 days	8 years 10 months 24 days
Exercisable, weighted average remaining contractual term		6 years 10 months 13 days
Vested or expected to vest, weighted average remaining contractual term		7 years 11 months 1 day
Outstanding, aggregate intrinsic value		$ 1,605,684	$ 9,073,673
Exercisable, aggregate intrinsic value		1,082,490
Vested or expected to vest, aggregate intrinsic value		$ 1,594,651

Stock-based compensation - Sche

Stock-based compensation - Schedule of fair value assumptions (Details) - Options to purchase common stock	10 Months Ended	12 Months Ended
	Dec. 31, 2014	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)	1.59%	1.23%	1.62%
Risk-free interest rate, maximum (as a percent)	2.71%	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)	75.80%	71.01%	72.98%
Expected term (in years)	6 years	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)	76.40%	74.20%	74.94%
Expected term (in years)	10 years	10 years	10 years

Stock-based compensation - Su60

Stock-based compensation - Summary of stock-based compensation expense (Details) - USD ($)	10 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Employee Service Share-Based Compensation Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 1,462,061	$ 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	648,001	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	$ 814,060	$ 4,137,398	$ 3,405,296

Income taxes - Schedule of effe

Income taxes - Schedule of effective income tax rate reconciliation (Details)	10 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal income tax expense at statutory rate (as a percent)	35.00%	35.00%	35.00%
State income tax, net of federal benefit (as a percent)	3.70%	5.00%	3.40%
Permanent differences (as a percent)	(0.30%)	0.00%	(0.20%)
Stock compensation (as a percent)	(34.30%)	(2.60%)	(34.10%)
Research credits (as a percent)	(5.30%)	1.90%	(6.30%)
Other, net (as a percent)		(0.10%)	0.40%	0.00%
Change in valuation allowance (as a percent)	1.20%	(39.20%)	1.80%
Effective tax rate (as a percent)	0.00%	0.00%	0.00%

Income taxes - Schedule of defe

Income taxes - Schedule of deferred tax assets and liabilities (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
U.S. and state net operating loss carryforwards	$ 24,322,172	$ 11,118,289
Accruals and other temporary differences	529,462	510,897
Amortization	32,171	33,824
Stock-based compensation	1,847,441	473,801
Tax credit carryforward	1,423,292	671,012
Total deferred tax assets	28,154,538	12,807,823
Less valuation allowance	(28,127,611)	(12,688,401)
Deferred tax assets	26,927	119,422
Deferred tax liabilities:
Stock-based compensation	(23,316)	(110,366)
Depreciation	(3,611)	(9,056)
Accruals and other temporary differences	0	0
Deferred tax liabilities	(26,927)	(119,422)
Net deferred tax assets	$ 0	$ 0

Income taxes - Narrative (Detai

Income taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Mar. 31, 2017	Dec. 31, 2015
Income Taxes [Line Items]
Deferred tax assets	$ 0		$ 0
Deferred tax assets, valuation allowance	28,127,611		12,688,401
Increase (decrease) in valuation allowance	15,400,000
U.S. Federal
Income Taxes [Line Items]
Net operating loss carryforward	61,000,000
Research and development tax credit carryforwards	1,200,000
U.S. State
Income Taxes [Line Items]
Net operating loss carryforward	58,500,000
Operating loss carryforward tax affected	4,500,000
Research and development tax credit carryforwards			$ 340,000
U.S. Federal and State
Income Taxes [Line Items]
Operating loss carryforwards that will increase additional paid in capital if used to reduce income taxes payable	$ 120,000
Scenario, Forecast | Accounting Standards Update 2016-09
Income Taxes [Line Items]
Deferred tax assets		$ 120,000
Deferred tax assets, valuation allowance		$ 120,000

Net loss per share (Details)

Net loss per share (Details) - shares	10 Months Ended	12 Months Ended
	Dec. 31, 2014	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	33,999,290	3,353,042	4,027,235
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	926,832	2,156,250	1,824,973
Unvested restricted common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	3,218,590	1,196,792	2,202,262
Series A Preferred Stock | Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	15,775,221	0	0
Series B Preferred Stock | Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	14,078,647	0	0

Segment Information (Details)

Segment Information (Details)	3 Months Ended								9 Months Ended	10 Months Ended	12 Months Ended
	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Sep. 30, 2016segment	Dec. 31, 2014USD ($)	Dec. 31, 2016USD ($)segment	Dec. 31, 2015USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment									2		2
Total revenue	$ 298,904	$ 599,074	$ 112,685	$ 0						$ 0	$ 1,010,663	$ 0
Interest income, net	$ 84,232	$ 97,726	$ 107,818	$ 103,333	$ 37,631	$ 14,637	$ 16,183	$ 3,577		18,946	393,109	72,028
Loss from operations										8,029,806	39,886,232	29,213,658
Operating Segments | Consumer Operations
Segment Reporting Information [Line Items]
Total revenue										0	1,010,663	0
Interest income, net										0	0	0
Loss from operations										898,504	10,023,137	7,892,584
Operating Segments | Drug Development
Segment Reporting Information [Line Items]
Total revenue										0	0	0
Interest income, net										0	0	0
Loss from operations										4,003,911	19,620,338	12,224,692
Corporate
Segment Reporting Information [Line Items]
Total revenue										0	0	0
Interest income, net										18,946	393,109	72,028
Loss from operations										$ 3,127,391	$ 10,242,757	$ 9,096,382

Related parties (Details)

Related parties (Details) - USD ($)	1 Months Ended	10 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2014	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			$ 20,000	$ 0
Royalties payable		$ 0	4,000	0	$ 0
Affiliated Entity
Related Party Transaction [Line Items]
License fees received		$ 34,000	$ 32,000	$ 61,000

Quarterly financial informati67

Quarterly financial information (unaudited) (Details) - USD ($)	3 Months Ended								10 Months Ended		12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Net product revenue	$ 291,099	$ 586,134	$ 112,685	$ 0						$ 0	$ 989,918	$ 0
Other revenue	7,805	12,940	0	0						0	20,745	0
Total revenue	298,904	599,074	112,685	0						0	1,010,663	0
Costs and expenses:
Cost of product revenue	133,706	221,090	110,931	197,020						0	662,747	0
Research and development	4,230,804	5,665,357	6,094,921	4,387,079	$ 3,309,055	$ 3,445,200	$ 3,190,178	$ 2,804,946		4,003,911	20,378,161	12,749,379
Selling, general and administrative	3,918,661	5,447,847	5,377,784	5,111,695	4,621,383	4,722,281	3,904,403	3,216,212		4,025,895	19,855,987	16,464,279
Total costs and expenses	8,283,171	11,334,294	11,583,636	9,695,794	7,930,438	8,167,481	7,094,581	6,021,158		8,029,806	40,896,895	29,213,658
Loss from operations	(7,984,267)	(10,735,220)	(11,470,951)	(9,695,794)	(7,930,438)	(8,167,481)	(7,094,581)	(6,021,158)
Interest income, net	84,232	97,726	107,818	103,333	37,631	14,637	16,183	3,577		18,946	393,109	72,028
Net loss	$ (7,900,035)	$ (10,637,494)	$ (11,363,133)	$ (9,592,461)	$ (7,892,807)	$ (8,152,844)	$ (7,078,398)	$ (6,017,581)	$ (8,010,860)	$ (8,010,860)	$ (39,493,123)	$ (29,141,630)
Net loss per share attributable to common stockholders - basic and diluted (in usd per share)	$ (0.48)	$ (0.65)	$ (0.71)	$ (0.61)	$ (0.51)	$ (0.53)	$ (0.47)	$ (0.59)		$ (4.57)	$ (2.43)	$ (2.08)
Weighted-average number of common shares outstanding — basic and diluted	16,619,596	16,361,617	16,105,555	15,843,532	15,551,800	15,290,435	15,034,764	10,179,955		1,753,024	16,233,985	14,032,916

Subsequent events (Details)

Subsequent events (Details) - 800 Boylston St - Subsequent Event	Jan. 27, 2017USD ($)ft²
Subsequent Event [Line Items]
Area of Real Estate Property | ft²	7,234
Operating leases, increase in future minimum payments due	$ 933,186
Security deposit	$ 126,595