Salarius Pharmaceuticals (SLRX) 10-Q 3 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	Apr. 28, 2017
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-Q
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		17,970,590

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 21,071,684	$ 22,416,040
Marketable securities	31,743,086	38,658,933
Accounts receivable	19,062	12,181
Inventory	414,322	454,132
Prepaid expenses and other current assets	1,585,715	925,983
Total current assets	54,833,869	62,467,269
Property and equipment, net	479,266	556,315
Other assets	64,800	64,800
Restricted cash	126,595	126,595
Total assets	55,504,530	63,214,979
Current liabilities:
Accounts payable	818,794	1,192,183
Accrued expenses and other current liabilities	2,311,405	2,587,573
Deferred revenue	80,637	88,344
Deferred rent, current portion	7,579	21,095
Total current liabilities	3,218,415	3,889,195
Deferred rent, net of current portion	59,111	8,398
Total liabilities	3,277,526	3,897,593
Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized at March 31, 2017 and December 31, 2016; none issued or outstanding at March 31, 2017 and December 31, 2016	0	0
Common stock, $0.0001 par value; 100,000,000 shares authorized at March 31, 2017 and December 31, 2016; 17,970,590 shares issued at March 31, 2017 and December 31, 2016, and 17,029,249 and 16,773,798 shares outstanding at March 31, 2017 and December 31, 2016, respectively	1,703	1,678
Additional paid-in capital	137,151,662	135,962,935
Accumulated other comprehensive loss	(12,353)	(1,614)
Accumulated deficit	(84,914,008)	(76,645,613)
Total stockholders' equity	52,227,004	59,317,386
Total liabilities and stockholders' equity	$ 55,504,530	$ 63,214,979

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	17,970,590	17,970,590
Common stock, shares outstanding (in shares)	17,029,249	16,773,798

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Net product revenue	$ 240,292	$ 0
Other revenue	2,255	0
Total revenue	242,547	0
Costs and expenses:
Cost of product revenue	79,106	197,020
Research and development	3,914,974	4,387,079
Selling, general and administrative	4,594,716	5,111,695
Total costs and expenses	8,588,796	9,695,794
Loss from operations	(8,346,249)	(9,695,794)
Interest income, net	77,854	103,333
Net loss	(8,268,395)	(9,592,461)
Net loss attributable to common stockholders	$ (8,268,395)	$ (9,592,461)
Net loss per share attributable to common stockholders - basic and diluted (in usd per share)	$ (0.49)	$ (0.61)
Weighted-average number of common shares outstanding — basic and diluted (in shares)	16,873,512	15,843,532

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (8,268,395)	$ (9,592,461)
Other comprehensive gain (loss):
Unrealized gain (loss) on available-for-sale securities	(10,739)	44,259
Comprehensive loss	$ (8,279,134)	$ (9,548,202)

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating activities
Net loss	$ (8,268,395)	$ (9,592,461)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	91,367	30,813
Stock-based compensation expense	1,188,752	1,518,161
Amortization and accretion on investments	2,454	46,129
Changes in operating assets and liabilities:
Accounts receivable	(6,881)	0
Inventory	39,810	(112,569)
Prepaid expenses and other current assets	(659,732)	(1,083,871)
Other assets	0	(64,800)
Accounts payable	(366,289)	594,639
Accrued expenses and other current liabilities	(276,168)	(517,446)
Deferred revenue	(7,707)	0
Deferred rent	37,197	7,781
Net cash used in operating activities	(8,225,592)	(9,173,624)
Investing activities
Purchases of marketable securities	(9,607,422)	(12,013,945)
Proceeds from maturities and sales of marketable securities	16,510,076	8,600,195
Purchases of property and equipment	(22,150)	(107,286)
Proceeds from sales of property and equipment	732	0
Net cash provided by (used in) investing activities	6,881,236	(3,521,036)
Financing activities
Proceeds from exercise of common stock	0	7,594
Net cash provided by financing activities	0	7,594
Net decrease in cash and cash equivalents	(1,344,356)	(12,687,066)
Cash and cash equivalents at beginning of period	22,416,040	66,686,695
Cash and cash equivalents at end of period	21,071,684	53,999,629
Supplemental cash flow information
Property and equipment purchases included in accounts payable and accrued expense at December 31, 2016 and 2015	7,100	106,680
Property and equipment purchases included in accounts payable and accrued expense at March 31, 2016	$ 0	$ 226,309

Organization and operations

Organization and operations	3 Months Ended
	Mar. 31, 2017
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 the Company describes 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. The Company operates as two reportable segments, Consumer Operations and Drug Development. See Note 11 for additional discussion and information on the reportable segments. The Company is subject to risks common to companies in the biotechnology and consumer products industries, including, but not limited to, risks of failure of pre-clinical studies and clinical trials, the need to obtain marketing approval for its drug product candidates, the need to successfully commercialize and gain market acceptance of its drug product candidates and its consumer products, dependence on key personnel, protection of proprietary technology, compliance with government regulations and development by competitors of alternative products. Liquidity The Company has incurred an accumulated deficit of $84,914,008 since inception and will require substantial additional capital to fund its research and development and commercialization and growth of its consumer brand and HOTSHOT. The Company had unrestricted cash, cash equivalents and marketable securities of $52,814,770 at March 31, 2017 . 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 and recent accounting pronouncements	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Summary of significant accounting policies and recent accounting pronouncements	Summary of significant accounting policies and recent accounting pronouncements The accompanying unaudited condensed consolidated financial statements reflect the application of certain significant accounting policies as described below and elsewhere in these notes to the condensed consolidated financial statements. As of March 31, 2017 , the Company’s significant accounting policies, which are detailed in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2016 (the “ 2016 10-K”), have not changed, other than as noted below. 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. The Company issues refunds to e-commerce customers, upon request, within 30 days of delivery. 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 three months ended March 31, 2017 . The vast majority of 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 March 31, 2017 . Advertising expense Advertising expense consists of media and production costs related to print and digital advertising. All advertising is expensed as incurred. Total advertising expenses are included in selling, general and administrative expenses in the condensed consolidated statement of operations, and were approximately $665,000 for the three months ended March 31, 2017 . There were no such costs for the three months ended March 31, 2016 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 expenses in the condensed consolidated statement of operations, and were approximately $34,000 for the three months ended March 31, 2017 . There were no such costs for the three months ended March 31, 2016 as the Company had not yet launched HOTSHOT. Unaudited interim financial information Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. Accordingly, these interim condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the 2016 10-K. The condensed consolidated financial statements as of March 31, 2017 , for the three months ended March 31, 2017 and 2016 , and the related information contained within the notes to the condensed consolidated financial statements, are unaudited. The unaudited condensed consolidated financial statements have been prepared on the same basis as annual audited consolidated financial statements, and in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s condensed consolidated financial position as of March 31, 2017 , and the statements of operations, comprehensive loss and cash flows for the three month periods ended March 31, 2017 and 2016 . The results for the three months ended March 31, 2017 are not necessarily indicative of results to be expected for the year ending December 31, 2017 , or any other future annual or interim periods. Basis of presentation and use of estimates The accompanying condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States ("GAAP"). Any reference in these notes to applicable guidance is meant to refer to the authoritative 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 clinical study accruals, estimates related to inventory realizability, stock-based compensation expense and amounts of expenses during the reported period. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions. Principles of consolidation The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries: TK Pharma, Inc., a Massachusetts Securities Corporation, and Flex Innovation Group LLC, a Delaware limited liability company, which contains the Company's consumer-related operations. All significant intercompany balances and transactions have been eliminated in consolidation. 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. Recent accounting pronouncements In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) . The ASU provides for a single comprehensive model for use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance. The accounting standard is effective for interim and annual periods beginning after December 15, 2016 with no early adoption permitted. In July 2015, the FASB deferred the effective date of this accounting update to annual periods beginning after December 15, 2017, along with an option to permit early adoption as of the original effective date. The Company is required to adopt the 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 No. 2016-08, Revenue from Contracts with Customers, Principal versus Agent Considerations (Reporting Revenue Gross versus Net), clarifying the implementation guidance on principal versus agent considerations. Specifically, an entity is required to determine whether the nature of a promise is to provide the specified good or service itself (that is, the entity is a principal) or to arrange for the good or service to be provided to the customer by the other party (that is, the entity is an agent). The determination influences the timing and amount of revenue recognition. The effective date and transition requirements for ASU No. 2016-08 are the same as the effective date and transition requirements for ASU No. 2014-09. The Company 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 July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330) . This ASU simplifies the measurement of inventory by requiring certain inventory to be measured at the lower of cost or net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The amendments in this ASU are effective for fiscal years beginning after December 15, 2016 and for interim periods therein. Subsequent measurement is unchanged for inventory measured using LIFO or the retail inventory method. The Company adopted this ASU as of March 31, 2017, which did not have a material impact on its condensed consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases . The ASU requires lessees to recognize assets and liabilities on their balance sheet for the right of use ("ROU") and obligations created by most leases, and to 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. While the Company is currently evaluating the effect this standard will have on its consolidated financial statements and timing of adoption, the Company expects that upon adoption, it will recognize ROU assets and lease liabilities and those amounts could be material. In March 2016, the FASB issued ASU No. 2016-09 Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. This ASU simplifies the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The guidance is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods. The Company adopted this standard as of March 31, 2017 and the following summarizes the effects of the adoption on the Company's unaudited condensed consolidated financial statements: Forfeitures - Prior to adoption, share-based compensation expense was recognized on a straight line basis, net of estimated forfeitures, such that expense was recognized only for share-based awards that were expected to vest. A forfeiture rate was estimated annually and revised, if necessary, in subsequent periods if actual forfeitures differed from initial estimates. Upon adoption, the Company no longer applies a forfeiture rate and instead will account for forfeitures as they occur. As the Company previously estimated forfeitures to determine stock-based compensation expense, this change resulted in a cumulative-effect adjustment as of January 1, 2017 to increase retained earnings by approximately $2,000 . Income taxes - Upon adoption of this standard, all excess tax benefits and tax deficiencies (including tax benefits of dividends on share-based payment awards) are recognized as income tax expense or benefit in the income statement. The tax effects of exercised or vested awards are treated as discrete items in the reporting period in which they occur. The Company did not recognized any discrete adjustments to income tax expense for the three months ended March 31, 2017, as the Company is in a full valuation allowance position. The Company has applied the modified retrospective adoption approach beginning in 2017. This cumulative-effect adjustment related to tax assets that had previously arisen from tax deductions for equity compensation expenses that were greater than the compensation recognized for financial reporting. These assets had been excluded from the deferred tax assets and liabilities totals on the balance sheet as a result of certain realization requirements previously included in ASC 718. The Company recorded a cumulative-effect adjustment of approximately $50,000 through retained earnings and deferred tax assets. However, due to the full valuation allowance, the only impact of the retrospective adoption is footnote presentation which will be presented in the December 31, 2017 year-end notes to the consolidated financial statements. Upon adoption, no other aspects of ASU 2016-09 had a material effect on the Company's consolidated financial statements or related footnote disclosures. 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 to have a material impact on its consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows , which amends ASU Topic 230. This update requires entities to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. As a result, entities will no longer be required to present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. When cash, cash equivalents, restricted cash and restricted cash equivalents are presented in more than one line item on the balance sheet, the new guidance requires a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheet. Entities will also have to disclose the nature of their restricted cash and restricted cash equivalent balances. The guidance is effective for fiscal years beginning after December 15, 2017 and interim periods within those years. Early adoption is permitted. Entities are required to apply the guidance retrospectively. The 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.

Fair value measurements

Fair value measurements	3 Months Ended
	Mar. 31, 2017
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 tables summarize the cash equivalents and marketable securities measured at fair value on a recurring basis as of March 31, 2017 and December 31, 2016 : Level 1 Level 2 Level 3 Balance as of March 31, 2017 Cash equivalents $ 11,115,898 $ — $ — $ 11,115,898 Marketable securities: Corporate debt securities — 3,102,128 — 3,102,128 Commercial paper — 4,594,668 — 4,594,668 U.S. government agency securities — 24,046,290 — 24,046,290 $ 11,115,898 $ 31,743,086 $ — $ 42,858,984 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 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 March 31, 2017 . After completing its validation procedures, the Company did not adjust or override any fair value carrying amounts as of March 31, 2017 . The carrying amounts reflected in the condensed consolidated balance sheets for cash, accounts receivable, prepaid expenses and other current assets, accounts payable, accrued expenses and other current liabilities approximate their fair values at March 31, 2017 and December 31, 2016, due to their short-term nature. The Company evaluates transfers between levels at the end of each reporting period. There were no transfers of assets or liabilities between Level 1 and Level 2 during the three months ended March 31, 2017 or the year ended December 31, 2016 . The Company had no financial assets or liabilities that were classified as Level 3 at any time during the three months ended March 31, 2017 or the year ended December 31, 2016.

Cash equivalents and marketable

Cash equivalents and marketable securities	3 Months Ended
	Mar. 31, 2017
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 March 31, 2017 and December 31, 2016 consisted of money market funds. Marketable securities as of March 31, 2017 and December 31, 2016 consisted of U.S. government agency securities, commercial paper and corporate debt securities. Management determines the appropriate classification of the securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. The Company classifies its marketable securities as available-for-sale pursuant to ASC 320, Investments – Debt and Equity Securities . Marketable securities are recorded at fair value, with unrealized gains and losses included as a component of accumulated other comprehensive income (loss) in stockholders’ equity and a component of total comprehensive income (loss) in the condensed consolidated statement of comprehensive income (loss), until realized. Realized gains and losses are included in investment income on a specific-identification basis. There were no realized gains on marketable securities during the three months ended March 31, 2017 , and there were immaterial realized gains on marketable securities during the three months ended March 31, 2016 . 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 March 31, 2017 and December 31, 2016 consisted of the following: Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of March 31, 2017 Current (due within 1 year): U.S. government agency securities $ 24,058,598 $ — $ (12,308 ) $ 24,046,290 Commercial paper 4,594,668 — — 4,594,668 Corporate debt securities 3,102,173 — (45 ) 3,102,128 Total $ 31,755,439 $ — $ (12,353 ) $ 31,743,086 Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of December 31, 2016 Current (due within 1 year): U.S. government agency securities $ 31,060,710 $ 2,912 $ (4,131 ) $ 31,059,491 Commercial paper 6,081,202 — — 6,081,202 Corporate debt securities 1,518,635 — (395 ) 1,518,240 Total $ 38,660,547 $ 2,912 $ (4,526 ) $ 38,658,933 The Company held eleven and six debt securities that were in an unrealized loss position at March 31, 2017 and December 31, 2016 , respectively, all of which have been in a continuous loss position for less than 12 months. The aggregate fair value of debt securities in an unrealized loss position was $27,148,418 and $16,519,620 at March 31, 2017 and December 31, 2016 , respectively. There were no individual securities that were in a significant unrealized loss position as of March 31, 2017 or December 31, 2016 . The Company evaluated its securities for other-than-temporary impairment and no marketable securities were considered to be other-than-temporarily impaired as of March 31, 2017 . At March 31, 2017 and December 31, 2016 , all investments held by the Company were classified as current. Investments classified as current have maturities of less than one year. Investments classified as noncurrent are those that (i) have a maturity greater than one year and (ii) management does not intend to liquidate within the next year, although these funds are available for use and therefore classified as available-for-sale.

Inventory

Inventory	3 Months Ended
	Mar. 31, 2017
Inventory Disclosure [Abstract]
Inventory	Inventory The Company began capitalizing inventory as of March 31, 2016, when it was determined that the inventory had a probable future economic benefit. Inventory has been recorded at cost as of March 31, 2017 and December 31, 2016 . Costs capitalized at March 31, 2017 and December 31, 2016 relate to HOTSHOT finished goods, as well as raw materials available to be used for future production runs. The following table presents inventory: March 31, 2017 December 31, 2016 Raw materials $ 19,628 $ 19,888 Finished goods 394,694 434,244 Total inventory $ 414,322 $ 454,132 There were no inventory write-offs during the three months ended March 31, 2017 . Write-offs totaled $185,298 for the three months ended March 31, 2016 and were included in cost of product revenue in the accompanying condensed 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.

Accrued expenses and other curr

Accrued expenses and other current liabilities	3 Months Ended
	Mar. 31, 2017
Payables and Accruals [Abstract]
Accrued expenses and other current liabilities	Accrued expenses and other current liabilities Accrued expenses and other current liabilities consisted of the following: March 31, 2017 December 31, 2016 Research and development costs $ 1,385,443 $ 938,665 Payroll and employee-related costs 583,689 1,453,665 Professional fees 188,414 153,219 Consumer product-related costs 153,859 42,024 Total $ 2,311,405 $ 2,587,573

Common stock

Common stock	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Common stock	Common stock As of March 31, 2017 , the Company had authorized 100,000,000 shares of common stock, $0.0001 par value per share. Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors. The Company does not intend to declare dividends for the foreseeable future. Restricted common stock to founders In March 2014, the Company sold 4,553,415 shares of restricted common stock to the founders of the Company ("recipients"), for $0.0004 per share, for total proceeds of $1,950 . In April 2014, based upon anti-dilution provisions granted to the founders, an additional 867,314 shares of restricted common stock were sold to the same founders, after which the anti-dilution provisions were terminated. The restricted common stock vested 25% upon issuance, and the remaining 75% vests ratably over four years , during which time the Company has the right to repurchase the unvested shares held by a recipient if the relationship between such recipient and the Company ceases. If the relationship terminates, the Company has 90 days to repurchase unvested shares at $0.0004 per share. Such shares are not accounted for as outstanding until they vest. There were 4,488,847 shares of restricted common stock outstanding as of March 31, 2017 . Unvested restricted common stock awards to non-employees are re-measured at each vest date and each financial reporting date. The following is a summary of restricted common stock activity: Number of Shares Weighted-Average Grant Date Fair Value Unvested at December 31, 2016 1,185,958 $ 0.10 Issued — — Vested (254,076 ) 0.10 Forfeited — — Unvested at March 31, 2017 931,882 $ 0.10 Restricted common stock to consultants In 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 8,735 shares of restricted common stock issued to consultants outstanding as of March 31, 2017 . Unvested restricted common stock awards to non-employees are re-measured at each vest date and each financial reporting date. The following is a summary of restricted common stock activity: Number of Shares Weighted-Average Grant Date Fair Value Unvested at December 31, 2016 10,834 $ 9.72 Issued — — Vested (1,375 ) 8.95 Forfeited — — Unvested at March 31, 2017 9,459 $ 9.83

Stock-based compensation

Stock-based compensation	3 Months Ended
	Mar. 31, 2017
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 March 31, 2017 , there were 769,327 shares remaining available for the grant of stock awards under the 2015 Plan. The Company has awarded stock options to its employees, directors, advisors and consultants, pursuant to the plans described above. Stock options subsequent to the completion of the Company's IPO are granted with an exercise price equal to the closing market price of the Company's common stock on the date of grant. Stock options generally vest over one to four years and have a contractual term of ten years . Stock options are valued using the Black-Scholes option pricing model and compensation cost is recognized based on the resulting value over the service period. 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 three months ended March 31, 2017 : Shares Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (in years) Aggregate Outstanding at December 31, 2016 2,156,250 $ 8.66 7.94 $ 1,605,684 Granted 587,500 4.58 Exercised — — Cancelled or forfeited (71,681 ) 11.93 Outstanding at March 31, 2017 2,672,069 $ 7.68 7.85 $ 1,031,433 Exercisable at March 31, 2017 1,128,717 $ 7.74 6.74 $ 740,304 Vested or expected to vest at March 31, 2017 2,672,069 $ 7.68 7.85 $ 1,031,433 Total stock-based compensation expense recognized for employee and non-employee restricted common stock, and stock options granted to employees and non-employees is included in the Company's condensed consolidated statement of operations and comprehensive loss as follows: Three Months Ended March 31, 2017 Three Months Ended March 31, 2016 Research and development $ 394,417 $ 595,466 Selling, general and administrative 794,335 922,695 Total $ 1,188,752 $ 1,518,161 As of March 31, 2017 , there was approximately $8,626,310 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 2.35 years . 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 March 31, 2017 , no shares of common stock have been purchased under the ESPP.

Income taxes

Income taxes	3 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income taxes	Income taxes Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax basis of assets and liabilities using statutory rates. A valuation allowance is recorded against deferred tax assets if it is more likely than not that some or all of the deferred tax assets will not be realized. Based upon the Company's history of operating losses and the uncertainty surrounding the realization of the favorable tax attributes in future tax returns, the Company has recorded a full valuation allowance against the Company’s otherwise recognizable net deferred tax assets. There was no significant income tax provision or benefit for the three months ended March 31, 2017 or 2016.

Net loss per share

Net loss per share	3 Months Ended
	Mar. 31, 2017
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 a net loss for the periods presented, diluted net loss per common share is the same as basic net loss per common share. The following potentially dilutive securities outstanding, prior to the use of the treasury stock method or if-converted method, have been excluded from the computation of diluted weighted-average shares outstanding for the periods indicated, because including them would have had an anti-dilutive impact: March 31, 2017 March 31, 2016 Options to purchase common stock 2,672,069 2,336,668 Unvested restricted common stock 941,341 1,963,145 Total 3,613,410 4,299,813

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2017
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, organize segments within the Company for making operating decisions and assessing financial performance. The Company evaluates the performance of its reportable segments based on revenue and operating income or loss. The accounting policies of the segments are the same as those described herein as well as those described in Note 2 to the audited consolidated financial statements in the 2016 Form 10-K. Corporate and unallocated amounts that do not relate to a reportable segment have been allocated to "Corporate". No asset information has been provided for the Company's reportable segments as management does not measure or allocate such assets on a reportable segment basis. Information for the Company's reportable segments for the three months ended March 31, 2017 and 2016 are as follows: Three Months Ended March 31, 2017 Consumer Operations Drug Development Corporate Consolidated Total revenue $ 242,547 — — $ 242,547 Interest income, net $ — — 77,854 $ 77,854 Loss from operations $ 1,987,810 3,828,281 2,530,158 $ 8,346,249 Three Months Ended March 31, 2016 Consumer Operations Drug Development Corporate Consolidated Total revenue $ — — — $ — Interest income, net $ — — 103,333 $ 103,333 Loss from operations $ 2,929,355 4,059,043 2,707,396 $ 9,695,794

Summary of significant accoun18

Summary of significant accounting policies and recent accounting pronouncements (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
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. The Company issues refunds to e-commerce customers, upon request, within 30 days of delivery. 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 and Refunds	Discounts provided to customers are accounted for as a reduction of net product revenue.
Accounts receivable	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.
Allowance for doubtful accounts	Receivables are evaluated for collectibility on a regular basis and an allowance for doubtful accounts is recorded, if necessary.
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 expenses in the condensed consolidated statement of operations
Basis of presentation	The accompanying condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States ("GAAP"). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification ("ASC") and Accounting Standards Update ("ASU") of the Financial Accounting Standards Board ("FASB").
Use of estimates	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company's management evaluates its estimates, which include, but are not limited to, estimates related to clinical study accruals, estimates related to inventory realizability, stock-based compensation expense and amounts of expenses during the reported period. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions.
Principles of consolidation	Principles of consolidation The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries: TK Pharma, Inc., a Massachusetts Securities Corporation, and Flex Innovation Group LLC, a Delaware limited liability company, which contains the Company's consumer-related operations. All significant intercompany balances and transactions have been eliminated in consolidation.
Concentration of 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.
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 is effective for interim and annual periods beginning after December 15, 2016 with no early adoption permitted. In July 2015, the FASB deferred the effective date of this accounting update to annual periods beginning after December 15, 2017, along with an option to permit early adoption as of the original effective date. The Company is required to adopt the 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 No. 2016-08, Revenue from Contracts with Customers, Principal versus Agent Considerations (Reporting Revenue Gross versus Net), clarifying the implementation guidance on principal versus agent considerations. Specifically, an entity is required to determine whether the nature of a promise is to provide the specified good or service itself (that is, the entity is a principal) or to arrange for the good or service to be provided to the customer by the other party (that is, the entity is an agent). The determination influences the timing and amount of revenue recognition. The effective date and transition requirements for ASU No. 2016-08 are the same as the effective date and transition requirements for ASU No. 2014-09. The Company 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 July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330) . This ASU simplifies the measurement of inventory by requiring certain inventory to be measured at the lower of cost or net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The amendments in this ASU are effective for fiscal years beginning after December 15, 2016 and for interim periods therein. Subsequent measurement is unchanged for inventory measured using LIFO or the retail inventory method. The Company adopted this ASU as of March 31, 2017, which did not have a material impact on its condensed consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases . The ASU requires lessees to recognize assets and liabilities on their balance sheet for the right of use ("ROU") and obligations created by most leases, and to 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. While the Company is currently evaluating the effect this standard will have on its consolidated financial statements and timing of adoption, the Company expects that upon adoption, it will recognize ROU assets and lease liabilities and those amounts could be material. In March 2016, the FASB issued ASU No. 2016-09 Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. This ASU simplifies the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The guidance is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods. The Company adopted this standard as of March 31, 2017 and the following summarizes the effects of the adoption on the Company's unaudited condensed consolidated financial statements: Forfeitures - Prior to adoption, share-based compensation expense was recognized on a straight line basis, net of estimated forfeitures, such that expense was recognized only for share-based awards that were expected to vest. A forfeiture rate was estimated annually and revised, if necessary, in subsequent periods if actual forfeitures differed from initial estimates. Upon adoption, the Company no longer applies a forfeiture rate and instead will account for forfeitures as they occur. As the Company previously estimated forfeitures to determine stock-based compensation expense, this change resulted in a cumulative-effect adjustment as of January 1, 2017 to increase retained earnings by approximately $2,000 . Income taxes - Upon adoption of this standard, all excess tax benefits and tax deficiencies (including tax benefits of dividends on share-based payment awards) are recognized as income tax expense or benefit in the income statement. The tax effects of exercised or vested awards are treated as discrete items in the reporting period in which they occur. The Company did not recognized any discrete adjustments to income tax expense for the three months ended March 31, 2017, as the Company is in a full valuation allowance position. The Company has applied the modified retrospective adoption approach beginning in 2017. This cumulative-effect adjustment related to tax assets that had previously arisen from tax deductions for equity compensation expenses that were greater than the compensation recognized for financial reporting. These assets had been excluded from the deferred tax assets and liabilities totals on the balance sheet as a result of certain realization requirements previously included in ASC 718. The Company recorded a cumulative-effect adjustment of approximately $50,000 through retained earnings and deferred tax assets. However, due to the full valuation allowance, the only impact of the retrospective adoption is footnote presentation which will be presented in the December 31, 2017 year-end notes to the consolidated financial statements. Upon adoption, no other aspects of ASU 2016-09 had a material effect on the Company's consolidated financial statements or related footnote disclosures. 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 to have a material impact on its consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows , which amends ASU Topic 230. This update requires entities to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. As a result, entities will no longer be required to present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. When cash, cash equivalents, restricted cash and restricted cash equivalents are presented in more than one line item on the balance sheet, the new guidance requires a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheet. Entities will also have to disclose the nature of their restricted cash and restricted cash equivalent balances. The guidance is effective for fiscal years beginning after December 15, 2017 and interim periods within those years. Early adoption is permitted. Entities are required to apply the guidance retrospectively. The 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.
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.
Cash equivalents	The Company considers all highly liquid investments with maturities of three months or less when purchased to be cash equivalents.
Marketable securities	Marketable securities as of March 31, 2017 and December 31, 2016 consisted of U.S. government agency securities, commercial paper and corporate debt securities. Management determines the appropriate classification of the securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. The Company classifies its marketable securities as available-for-sale pursuant to ASC 320, Investments – Debt and Equity Securities . Marketable securities are recorded at fair value, with unrealized gains and losses included as a component of accumulated other comprehensive income (loss) in stockholders’ equity and a component of total comprehensive income (loss) in the condensed consolidated statement of comprehensive income (loss), until realized. Realized gains and losses are included in investment income on a specific-identification basis. There were no realized gains on marketable securities during the three months ended March 31, 2017 , and there were immaterial realized gains on marketable securities during the three months ended March 31, 2016 . 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.

Fair value measurements (Tables

Fair value measurements (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Summary of Cash Equivalents and Marketable Securities Measured at Fair Value on a Recurring Basis	The following tables summarize the cash equivalents and marketable securities measured at fair value on a recurring basis as of March 31, 2017 and December 31, 2016 : Level 1 Level 2 Level 3 Balance as of March 31, 2017 Cash equivalents $ 11,115,898 $ — $ — $ 11,115,898 Marketable securities: Corporate debt securities — 3,102,128 — 3,102,128 Commercial paper — 4,594,668 — 4,594,668 U.S. government agency securities — 24,046,290 — 24,046,290 $ 11,115,898 $ 31,743,086 $ — $ 42,858,984 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

Cash equivalents and marketab20

Cash equivalents and marketable securities (Tables)	3 Months Ended
	Mar. 31, 2017
Cash and Cash Equivalents [Abstract]
Schedule of Marketable Securities	Marketable securities at March 31, 2017 and December 31, 2016 consisted of the following: Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of March 31, 2017 Current (due within 1 year): U.S. government agency securities $ 24,058,598 $ — $ (12,308 ) $ 24,046,290 Commercial paper 4,594,668 — — 4,594,668 Corporate debt securities 3,102,173 — (45 ) 3,102,128 Total $ 31,755,439 $ — $ (12,353 ) $ 31,743,086 Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of December 31, 2016 Current (due within 1 year): U.S. government agency securities $ 31,060,710 $ 2,912 $ (4,131 ) $ 31,059,491 Commercial paper 6,081,202 — — 6,081,202 Corporate debt securities 1,518,635 — (395 ) 1,518,240 Total $ 38,660,547 $ 2,912 $ (4,526 ) $ 38,658,933

Inventory (Tables)

Inventory (Tables)	3 Months Ended
	Mar. 31, 2017
Inventory Disclosure [Abstract]
Schedule of Inventory, Net	The following table presents inventory: March 31, 2017 December 31, 2016 Raw materials $ 19,628 $ 19,888 Finished goods 394,694 434,244 Total inventory $ 414,322 $ 454,132

Accrued expenses and other cu22

Accrued expenses and other current liabilities (Tables)	3 Months Ended
	Mar. 31, 2017
Payables and Accruals [Abstract]
Schedule of accrued expenses	Accrued expenses and other current liabilities consisted of the following: March 31, 2017 December 31, 2016 Research and development costs $ 1,385,443 $ 938,665 Payroll and employee-related costs 583,689 1,453,665 Professional fees 188,414 153,219 Consumer product-related costs 153,859 42,024 Total $ 2,311,405 $ 2,587,573
Schedule of other current liabilities	Accrued expenses and other current liabilities consisted of the following: March 31, 2017 December 31, 2016 Research and development costs $ 1,385,443 $ 938,665 Payroll and employee-related costs 583,689 1,453,665 Professional fees 188,414 153,219 Consumer product-related costs 153,859 42,024 Total $ 2,311,405 $ 2,587,573

Common stock (Tables)

Common stock (Tables)	3 Months Ended
	Mar. 31, 2017
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 Unvested at December 31, 2016 10,834 $ 9.72 Issued — — Vested (1,375 ) 8.95 Forfeited — — Unvested at March 31, 2017 9,459 $ 9.83 The following is a summary of restricted common stock activity: Number of Shares Weighted-Average Grant Date Fair Value Unvested at December 31, 2016 1,185,958 $ 0.10 Issued — — Vested (254,076 ) 0.10 Forfeited — — Unvested at March 31, 2017 931,882 $ 0.10

Stock-based compensation (Table

Stock-based compensation (Tables)	3 Months Ended
	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of stock option activity	The following table summarizes stock option activity for employees and non-employees for the three months ended March 31, 2017 : Shares Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (in years) Aggregate Outstanding at December 31, 2016 2,156,250 $ 8.66 7.94 $ 1,605,684 Granted 587,500 4.58 Exercised — — Cancelled or forfeited (71,681 ) 11.93 Outstanding at March 31, 2017 2,672,069 $ 7.68 7.85 $ 1,031,433 Exercisable at March 31, 2017 1,128,717 $ 7.74 6.74 $ 740,304 Vested or expected to vest at March 31, 2017 2,672,069 $ 7.68 7.85 $ 1,031,433
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 condensed consolidated statement of operations and comprehensive loss as follows: Three Months Ended March 31, 2017 Three Months Ended March 31, 2016 Research and development $ 394,417 $ 595,466 Selling, general and administrative 794,335 922,695 Total $ 1,188,752 $ 1,518,161

Net loss per share (Tables)

Net loss per share (Tables)	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Schedule of antidilutive securities excluded from computation of earnings per share	The following potentially dilutive securities outstanding, prior to the use of the treasury stock method or if-converted 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: March 31, 2017 March 31, 2016 Options to purchase common stock 2,672,069 2,336,668 Unvested restricted common stock 941,341 1,963,145 Total 3,613,410 4,299,813

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Schedule of Information for the Company's Operating Segments	Information for the Company's reportable segments for the three months ended March 31, 2017 and 2016 are as follows: Three Months Ended March 31, 2017 Consumer Operations Drug Development Corporate Consolidated Total revenue $ 242,547 — — $ 242,547 Interest income, net $ — — 77,854 $ 77,854 Loss from operations $ 1,987,810 3,828,281 2,530,158 $ 8,346,249 Three Months Ended March 31, 2016 Consumer Operations Drug Development Corporate Consolidated Total revenue $ — — — $ — Interest income, net $ — — 103,333 $ 103,333 Loss from operations $ 2,929,355 4,059,043 2,707,396 $ 9,695,794

Organization and operations (De

Organization and operations (Details)	3 Months Ended
	Mar. 31, 2017USD ($)segment	Dec. 31, 2016USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments | segment	2
Retained earnings (accumulated deficit)	$ (84,914,008)	$ (76,645,613)
Cash, cash equivalents, and marketable securities	$ 52,814,770

Summary of significant accoun28

Summary of significant accounting policies and recent accounting pronouncements - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Jan. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Refund period from day of shipment (in days)	30 days
Advertising expense	$ 665,000	$ 0
Shipping and handling costs	34,000	$ 0
Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets	50,000
Retained Earnings | Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment	$ 50,000		$ 2,000

Fair value measurements (Detail

Fair value measurements (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Marketable securities:
Fair Value	$ 31,743,086	$ 38,658,933
Corporate debt securities
Marketable securities:
Fair Value	3,102,128	1,518,240
Commercial paper
Marketable securities:
Fair Value	4,594,668	6,081,202
US government agency securities
Marketable securities:
Fair Value	24,046,290	31,059,491
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	11,115,898	11,681,074
Marketable securities:
Total assets	42,858,984	50,340,007
Fair Value, Measurements, Recurring | Corporate debt securities
Marketable securities:
Fair Value	3,102,128	1,518,240
Fair Value, Measurements, Recurring | Commercial paper
Marketable securities:
Fair Value	4,594,668	6,081,202
Fair Value, Measurements, Recurring | US government agency securities
Marketable securities:
Fair Value	24,046,290	31,059,491
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	11,115,898	11,681,074
Marketable securities:
Total assets	11,115,898	11,681,074
Fair Value, Measurements, Recurring | Level 1 | Corporate debt securities
Marketable securities:
Fair Value	0	0
Fair Value, Measurements, Recurring | Level 1 | Commercial paper
Marketable securities:
Fair Value	0	0
Fair Value, Measurements, Recurring | Level 1 | US government agency securities
Marketable securities:
Fair Value	0	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Marketable securities:
Total assets	31,743,086	38,658,933
Fair Value, Measurements, Recurring | Level 2 | Corporate debt securities
Marketable securities:
Fair Value	3,102,128	1,518,240
Fair Value, Measurements, Recurring | Level 2 | Commercial paper
Marketable securities:
Fair Value	4,594,668	6,081,202
Fair Value, Measurements, Recurring | Level 2 | US government agency securities
Marketable securities:
Fair Value	24,046,290	31,059,491
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Marketable securities:
Total assets	0	0
Fair Value, Measurements, Recurring | Level 3 | Corporate debt securities
Marketable securities:
Fair Value	0	0
Fair Value, Measurements, Recurring | Level 3 | Commercial paper
Marketable securities:
Fair Value	0	0
Fair Value, Measurements, Recurring | Level 3 | US government agency securities
Marketable securities:
Fair Value	$ 0	$ 0

Cash equivalents and marketab30

Cash equivalents and marketable securities (Details)	Mar. 31, 2017USD ($)security	Dec. 31, 2016USD ($)security
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 31,755,439	$ 38,660,547
Unrealized Gains	0	2,912
Unrealized Losses	(12,353)	(4,526)
Fair Value	$ 31,743,086	$ 38,658,933
Number of debt securities held | security	11	6
Aggregate fair value of debt securities in an unrealized loss position	$ 27,148,418	$ 16,519,620
US government agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	24,058,598	31,060,710
Unrealized Gains	0	2,912
Unrealized Losses	(12,308)	(4,131)
Fair Value	24,046,290	31,059,491
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,594,668	6,081,202
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	4,594,668	6,081,202
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,102,173	1,518,635
Unrealized Gains	0	0
Unrealized Losses	(45)	(395)
Fair Value	$ 3,102,128	$ 1,518,240

Inventory (Details)

Inventory (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Inventory Disclosure [Abstract]
Raw materials	$ 19,628		$ 19,888
Finished goods	394,694		434,244
Total inventory	414,322		$ 454,132
Write-off of inventory	$ 0	$ 185,298

Accrued expenses and other cu32

Accrued expenses and other current liabilities (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Research and development costs	$ 1,385,443	$ 938,665
Payroll and employee-related costs	583,689	1,453,665
Professional fees	188,414	153,219
Consumer product-related costs	153,859	42,024
Total	$ 2,311,405	$ 2,587,573

Common stock - Narrative (Detai

Common stock - Narrative (Details) - USD ($)	1 Months Ended		3 Months Ended	12 Months Ended
	Apr. 30, 2014	Mar. 31, 2014	Mar. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)			100,000,000	100,000,000
Common stock, par value (in usd per share)			$ 0.0001	$ 0.0001
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [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 (in days)			90 days
Restricted common stock, repurchase price (in usd per share)			$ 0.0004
Restricted common stock, shares outstanding			4,488,847
Restricted stock | Non-employee Consultants and Advisers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock, shares sold				18,194
Restricted common stock, repurchase period (in days)			90 days
Restricted common stock, repurchase price (in usd per share)			$ 0.0001
Restricted common stock, shares outstanding			8,735
Restricted stock | Vests upon issuance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock, percent vested			25.00%
Restricted stock | Vests ratably over four years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock, percent vested			75.00%
Restricted common stock, vesting period (in years)			4 years

Common stock - Restricted commo

Common stock - Restricted common stock activity (Details) - Restricted stock	3 Months Ended
	Mar. 31, 2017$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance, unvested, number of shares | shares	1,185,958
Issued, number of shares | shares	0
Vested, number of shares | shares	(254,076)
Forfeited, number of shares | shares	0
Ending balance, unvested, number of shares | shares	931,882
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning balance, weighted average grant date fair value (in usd per share) | $ / shares	$ 0.10
Issued, weighted average grant date fair value (in usd per share) | $ / shares	0
Vested, weighted average grant date fair value (in usd per share) | $ / shares	0.10
Forfeited, weighted average grant date fair value (in usd per share) | $ / shares	0
Ending balance, weighted average grant date fair value (in usd per share) | $ / shares	$ 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, unvested, number of shares | shares	10,834
Issued, number of shares | shares	0
Vested, number of shares | shares	(1,375)
Forfeited, number of shares | shares	0
Ending balance, unvested, number of shares | shares	9,459
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning balance, weighted average grant date fair value (in usd per share) | $ / shares	$ 9.72
Issued, weighted average grant date fair value (in usd per share) | $ / shares	0
Vested, weighted average grant date fair value (in usd per share) | $ / shares	8.95
Forfeited, weighted average grant date fair value (in usd per share) | $ / shares	0
Ending balance, weighted average grant date fair value (in usd per share) | $ / shares	$ 9.83

Stock-based compensation - Narr

Stock-based compensation - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Sep. 30, 2014	Apr. 30, 2014	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 8,626,310
Unrecognized compensation cost, recognition period (in years)	2 years 4 months 6 days
Employee stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, contractual term	10 years
Minimum | Employee stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period (in years)	1 year
Maximum | Employee stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period (in years)	4 years
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
2015 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remaining available for grant of stock awards	769,327

Stock-based compensation - Summ

Stock-based compensation - Summary of stock option activity (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Shares
Shares outstanding, Beginning Balance	2,156,250
Shares granted	587,500
Shares exercised	0
Shares canceled or forfeited	(71,681)
Shares outstanding, Ending Balance	2,672,069	2,156,250
Shares exercisable	1,128,717
Shares vested or expected to vest	2,672,069
Weighted-Average Exercise Price
Shares outstanding, weighted-average exercise price, Beginning Balance (in usd per share)	$ 8.66
Shares granted, weighted-average exercise price (in usd per share)	4.58
Shares exercised, weighted-average exercise price (in usd per share)	0
Shares canceled or forfeited, weighted-average exercise price (in usd per share)	11.93
Shares outstanding, weighted-average exercise price, Ending Balance (in usd per share)	7.68	$ 8.66
Shares exercisable, weighted-average exercise price (in usd per share)	7.74
Shares vested or expected to vest, weighted-average exercise price (in usd per share)	$ 7.68
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, weighted-average remaining contractual term (in years)	7 years 10 months 6 days	7 years 11 months 9 days
Exercisable, weighted-average remaining contractual term (in years)	6 years 8 months 27 days
Vested or expected to vest, weighted-average remaining contractual term (in years)	7 years 10 months 6 days
Outstanding, aggregate intrinsic value	$ 1,031,433	$ 1,605,684
Exercisable, aggregate intrinsic value	740,304
Vested or expected to vest, aggregate intrinsic value	$ 1,031,433

Stock-based compensation - Su37

Stock-based compensation - Summary of stock-based compensation expense (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Employee Service Share-Based Compensation Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 1,188,752	$ 1,518,161
Research and development
Employee Service Share-Based Compensation Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	394,417	595,466
Selling, general and administrative
Employee Service Share-Based Compensation Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 794,335	$ 922,695

Income taxes (Details)

Income taxes (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Income tax provision (benefit)	$ 0	$ 0

Net loss per share (Details)

Net loss per share (Details) - shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	3,613,410	4,299,813
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 (in shares)	2,672,069	2,336,668
Unvested restricted common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	941,341	1,963,145

Segment Information (Details)

Segment Information (Details)	3 Months Ended
	Mar. 31, 2017USD ($)segment	Mar. 31, 2016USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment	2
Segment Reporting Information [Line Items]
Total revenue	$ 242,547	$ 0
Interest income, net	77,854	103,333
Loss from operations	8,346,249	9,695,794
Operating Segments | Consumer Operations
Segment Reporting Information [Line Items]
Total revenue	242,547	0
Interest income, net	0	0
Loss from operations	1,987,810	2,929,355
Operating Segments | Drug Development
Segment Reporting Information [Line Items]
Total revenue	0	0
Interest income, net	0	0
Loss from operations	3,828,281	4,059,043
Corporate
Segment Reporting Information [Line Items]
Total revenue	0	0
Interest income, net	77,854	103,333
Loss from operations	$ 2,530,158	$ 2,707,396