Organization and operations	9 Months Ended
Sep. 30, 2018
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 was focused on developing innovative and proprietary treatments for muscle cramps, spasms and spasticity associated with severe neurological conditions. In June 2018, the Company announced that it was ending its ongoing Phase 2 clinical trials of FLX-787 in patients with motor neuron disease ("MND"), primarily with amyotrophic lateral sclerosis ("ALS"), and in patients with Charcot-Marie-Tooth disease ("CMT"), due to oral tolerability concerns observed in both studies. Additionally, in June 2018, the Company initiated a process to explore a range of strategic alternatives for enhancing stockholder value, including the potential sale or merger of the Company. Wedbush PacGrow has been engaged to act as the Company’s strategic financial advisor. The Company also announced the restructuring of the organization to reduce its cost structure in order to preserve liquidity. In connection with the restructuring plan, the Company reduced its workforce by approximately 60%, with the reduction completed as of September 30, 2018. While the strategic assessment is ongoing, the Company will continue to operate with a reduced internal team that will focus their efforts on limited research and development activities and operating its consumer business, which sells HOTSHOT®, the Company's consumer product launched in 2016 to prevent and treat exercise-associated muscle cramps. The Company's evaluation of strategic alternatives and its restructuring plans entails significant risks and uncertainties, including the risks and uncertainties set forth in Item 1A under the heading "Risk Factors" and Item 2 under the heading "Management's Discussion and Analysis of Financial Condition and Results of Operations" of this Quarterly Report on Form 10-Q and in the Company's Annual Report on Form 10-K. There can be no assurance that the Company's evaluation of potential strategic alternatives will result in any transaction. The Company operates as two reportable segments, Consumer Operations and Drug Development. See Note 12 for additional discussion and information on the reportable segments. Liquidity The Company incurred a loss of $2,638,373 for the three months ended September 30, 2018, a loss of $19,913,472 for the nine months ended September 30, 2018 and had an accumulated deficit of $130,952,530 as of September 30, 2018. The Company had unrestricted cash and cash equivalents of $12,961,126 at September 30, 2018. The Company's operating plan assumes limited research and development activities and that the Consumer Operations segment will continue to sell HOTSHOT. In the event that the Company does not complete a sale or merger, the Company (i) may elect to pursue a dissolution and liquidation of the Company or (ii) may continue to market HOTSHOT and operate its consumer business. If the Company dissolves and liquidates, the Company's common stockholders may lose their entire investment. The amount of assets available for distribution to the Company's stockholders will depend heavily on the timing of such liquidation as well as the amount of cash that will be needed for commitments and contingent liabilities. Based on the Company's operating plan, the Company believes that its existing cash and cash equivalents will be sufficient to allow the Company to fund its current operating plan for at least 12 months from the date the financial statements are issued. The Company cannot predict the outcome of its strategic assessment or whether and to what extent it will resume drug development activities for FLX-787 or other drug product candidates and to what extent it will promote and sell HOTSHOT or other consumer products in the future. Accordingly, it is difficult to predict future cash needs. Management does expect the Company to incur losses for the foreseeable future. The Company's ability to achieve profitability in the future is dependent upon achieving a level of revenues adequate to support the Company's cost structure. The Company may never achieve profitability, and unless and until it does, the Company will continue to need to raise additional capital. If the Company raises funds through the issuance of additional equity, whether through private placements or additional public offerings, such an issuance would dilute the stockholders' ownership in the Company. There can be no assurances, however, that additional funding will be available on terms acceptable to the Company, or at all.

Organization and operations

The Company

Flex Pharma, Inc. (the "Company") is a biotechnology company that was focused on developing innovative and proprietary treatments for muscle cramps, spasms and spasticity associated with severe neurological conditions. In June 2018, the Company announced that it was ending its ongoing Phase 2 clinical trials of FLX-787 in patients with motor neuron disease ("MND"), primarily with amyotrophic lateral sclerosis ("ALS"), and in patients with Charcot-Marie-Tooth disease ("CMT"), due to oral tolerability concerns observed in both studies.

Additionally, in June 2018, the Company initiated a process to explore a range of strategic alternatives for enhancing stockholder value, including the potential sale or merger of the Company. Wedbush PacGrow has been engaged to act as the Company’s strategic financial advisor. The Company also announced the restructuring of the organization to reduce its cost structure in order to preserve liquidity. In connection with the restructuring plan, the Company reduced its workforce by approximately 60%, with the reduction completed as of September 30, 2018. While the strategic assessment is ongoing, the Company will continue to operate with a reduced internal team that will focus their efforts on limited research and development activities and operating its consumer business, which sells HOTSHOT®, the Company's consumer product launched in 2016 to prevent and treat exercise-associated muscle cramps.

The Company's evaluation of strategic alternatives and its restructuring plans entails significant risks and uncertainties, including the risks and uncertainties set forth in Item 1A under the heading "Risk Factors" and Item 2 under the heading "Management's Discussion and Analysis of Financial Condition and Results of Operations" of this Quarterly Report on Form 10-Q and in the Company's Annual Report on Form 10-K. There can be no assurance that the Company's evaluation of potential strategic alternatives will result in any transaction.

The Company operates as two reportable segments, Consumer Operations and Drug Development. See Note 12 for additional discussion and information on the reportable segments.

Liquidity

The Company incurred a loss of $2,638,373 for the three months ended September 30, 2018, a loss of $19,913,472 for the nine months ended September 30, 2018 and had an accumulated deficit of $130,952,530 as of September 30, 2018. The Company had unrestricted cash and cash equivalents of $12,961,126 at September 30, 2018. The Company's operating plan assumes limited research and development activities and that the Consumer Operations segment will continue to sell HOTSHOT.

In the event that the Company does not complete a sale or merger, the Company (i) may elect to pursue a dissolution and liquidation of the Company or (ii) may continue to market HOTSHOT and operate its consumer business. If the Company dissolves and liquidates, the Company's common stockholders may lose their entire investment. The amount of assets available for distribution to the Company's stockholders will depend heavily on the timing of such liquidation as well as the amount of cash that will be needed for commitments and contingent liabilities.

Based on the Company's operating plan, the Company believes that its existing cash and cash equivalents will be sufficient to allow the Company to fund its current operating plan for at least 12 months from the date the financial statements are issued.

The Company cannot predict the outcome of its strategic assessment or whether and to what extent it will resume drug development activities for FLX-787 or other drug product candidates and to what extent it will promote and sell HOTSHOT or other consumer products in the future. Accordingly, it is difficult to predict future cash needs. Management does expect the Company to incur losses for the foreseeable future. The Company's ability to achieve profitability in the future is dependent upon achieving a level of revenues adequate to support the Company's cost structure. The Company may never achieve profitability, and unless and until it does, the Company will continue to need to raise additional capital. If the Company raises funds through the issuance of additional equity, whether through private placements or additional public offerings, such an issuance would dilute the stockholders' ownership in the Company. There can be no assurances, however, that additional funding will be available on terms acceptable to the Company, or at all.