Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Jun. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies Research, Supply and License Agreements Roche Master Supply Agreement The Company is a party to a master supply agreement with Roche Diagnostics Corporation (“Roche”) pursuant to which Roche will custom manufacture certain products for the Company. The agreement specifies a minimum purchase requirement for certain custom manufactured products through December 31, 2024. As of June 30, 2021, the Company’s purchase commitments under the agreement totaled $10.5 million, with $3.5 million committed as payments each year from 2022 to 2024. Research and development expenses related to this agreement totaled $1.3 million and $1.3 million during the three months ended June 30, 2021 and 2020, respectively, and $5.7 million and $2.6 million during the six months ended June 30, 2021 and 2020, respectively. MIT Research Agreement In September 2019, the Company entered into a research agreement with the Massachusetts Institute of Technology (“MIT”) pursuant to which the Company is obligated to reimburse MIT up to $4.1 million for specified direct and indirect costs to be incurred from January 2020 through December 2022 for specified research activities conducted for the Company (the “2019 MIT Agreement”). As of June 30, 2021 and 2020, the Company paid MIT $2.4 million and $1.2 million, respectively, towards the total committed amount. Research and development expenses related to this agreement were $0.3 million during each of the three months ended June 30, 2021 and 2020 and $0.7 million during each of the six months ended June 30, 2021 and 2020. There were no amounts payable by the Company under the agreement as of June 30, 2021. The 2019 MIT Agreement expires in December 2022 and may be extended thereafter by mutual agreement of the parties. MIT Exclusive Patent License Agreement The Company is a party to an exclusive patent license agreement with MIT pursuant to which the Company received an exclusive license under the licensed patent rights to develop, manufacture and commercialize any product containing both Certain RNA sequences and certain lipid products, referred to as a “licensed product”. Under the licensed patent rights, the Company is permitted to develop, manufacture and commercialize the licensed products for the delivery of coding RNA components to treat disease in humans. The Company has the right to grant sublicenses under this license. The patent rights licensed to the Company by MIT include claims that cover certain of the Company’s customized lipid nanoparticles used for delivery of coding RNA components in its MRT platform, including products that may be developed under the Company’s collaboration with Sanofi. The Company is also obligated to make milestone payments to MIT aggregating up to $1.375 million upon the achievement of specified clinical and regulatory milestones with respect to each licensed product and $1.250 million upon the Company’s first commercial sale of each licensed product, and to pay royalties of a low single-digit percentage to MIT based on the Company’s, and any of its affiliates’ and sublicensees’, net sales of licensed products. The royalties are p a yable on a product-by-product and country-by-country basis, and may be reduced in specified circumstances. The Company’s obligation to make royalty payments extends with respect to a licensed product in a country until four years past the expiration of the last-to-expire patent or patent application licensed from MIT covering the licensed product in the country. In addition, the Company is obligated to pay MIT a low double-digit percentage of the portion of income from sublicensees that the Company ascribes to the MIT-licensed patents, excluding royalties on net sales and research support payments. Pursuant to such provision, during the six months ended June 30, 2021, the Company paid $ 3.4 million to MIT which included $ 2.5 million as MIT’s share of sublicense income with respect to the payments the Company received in 2020 under the Second Sanofi Amendment and the Securities Purchase Agreement and $0.9 million as MIT’s share of sublicense income with respect to the milestones the Company achieved in 2021 under the Amended Sanofi Agreement. Future amounts that the Company may owe to MIT will depend upon the relative value of the patents the Company licensed from MIT and sublicensed to Sanofi as compared to the other rights that the Company licensed to Sanofi. The determination of the relative value of such rights is subject to a process described in the Company’s license agreement with MIT. Additionally, in the quarter ended June 30, 2021, the Company paid a total of $0.7 million due to the achievement of specified milestones in accordance with the license agreement with MIT. Indemnification Agreements In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its Board of Directors that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company does not believe that the outcome of any claims under indemnification arrangements will have a material effect on its financial position, results of operations or cash flows, and it has not accrued any liabilities related to such obligations in its condensed consolidated financial statements as of June 30, 2021 and December 31, 2020. Legal Proceedings The Company is not a party to any litigation and does not have contingency reserves established for any litigation liabilities.