Related Party Transactions	9 Months Ended
Related Party Transactions	Sep. 30, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions The Company receives clinical advisory services from Weatherden Ltd. (“Weatherden”) under agreements that were entered into during 2017 and 2018. Duncan McHale, the Company’s Chief Medical Officer, is a part owner of Weatherden. During the nine months ended September 30, 2020 and 2019, the Company paid Weatherden $0.5 million and $0.7 million, respectively. As of September 30, 2020 and 2019, the amounts due to Weatherden under the supply of service agreement were approximately $30.0 thousand and $0.1 million, respectively. In June 2018, the Company entered into a subleasing arrangement with Ring Therapeutics, Inc. (formerly VL46, Inc.), an affiliate of one of its stockholders, Flagship Venture Funds. Under the terms of the sublease, the Company invoiced Ring Therapeutics for an aggregate $0.9 million in rent payments which were due during the period from July 1, 2018 through April 30, 2020, the sublease expiration date, plus related taxes and lease operating costs. For the nine-months ended September 30, 2020, $0.3 million related to this sublease, inclusive of rent payments, taxes and operating expenses, has been recorded as an offset to operating expense within the unaudited condensed consolidated statements of operations and comprehensive loss. The Company entered into a consulting agreement with David Epstein (as amended, the "Consulting Agreement"), the Company's Chairman of the Board, effective September 16, 2019 pursuant to which Mr. Epstein will provide strategic advisory and other consulting services to the Company. As amended on October 15, 2020, the Consulting Agreement will continue until June 30, 2021 unless terminated earlier by either Mr. Epstein or the Company upon 30 days’ notice, or 24 hours’ notice by the non-breaching party in the event of a breach. In accordance with the terms of the Consulting Agreement, on September 16, 2019, Mr. Epstein was granted an option to purchase 75,000 shares of the Company’s common stock, which award vests in 36 equal monthly installments subject to his continued provision of consulting services to the Company pursuant to the Consulting Agreement on the applicable vesting dates. Under the Consulting Agreement, Mr. Epstein also is entitled to receive (i) an annual equity award on each anniversary of the effective date of the Consulting Agreement in the form of an option to purchase shares of the Company’s common stock having an aggregate grant date fair market value equal to approximately $0.2 million, as determined by the Board in its discretion based on customary option pricing methodologies, which award vests in 12 equal monthly installment following the grant date, subject to his continued provision of consulting services to the Company pursuant to the Consulting Agreement on the applicable vesting date, and (ii) an aggregate annual cash consulting fee of $0.3 million for his consulting services. All of the foregoing options, to the extent then outstanding, will be subject to accelerated vesting upon the occurrence of a change in control of the Company. On October 11, 2020, in connection with the commencement of his second year of service as a consultant to the Company, Mr. Epstein was granted an annual equity award in the form of an option to purchase 44,743 shares of the Company’s common stock, which award vests in nine equal monthly installments, in each case subject to his continued provision of consulting services to the Company pursuant to the Consulting Agreement on the applicable vesting dates.