Leases - Additional Information (Details) $ in Thousands	1 Months Ended	12 Months Ended
	May 30, 2018 ft²	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2020	Jan. 01, 2019 USD ($)
Lease Agreements [Line Items]
Cash paid for lease liabilities		$ 4,148
Total rent expense			$ 1,649	$ 1,194
Office and Laboratory Space | CoStim Pharmaceuticals, Inc
Lease Agreements [Line Items]
Operating sublease, expiration period		2018-03
Sublease payments received from third-party tenant			$ 231	$ 305
Massachusetts
Lease Agreements [Line Items]
Lease term		10 years
Renewal terms of lease		5 years
Operating lease, expiration period		2027-02
Lease commenced period		2017-04
Operting lease, incentives						$ 4,803
Massachusetts | Sublease agreement with EQRx | Office Space
Lease Agreements [Line Items]
Sublease commenced date		Jan. 01, 2020
Massachusetts | Sublease agreement with EQRx | Office Space | Scenario, Forecast
Lease Agreements [Line Items]
Lease term					3 years
Massachusetts | Lease Amendment
Lease Agreements [Line Items]
Lease term	10 years
Lease term, description	In May 2018, the Company executed an amendment to lease an additional 33,526 square feet at 50 Hampshire Street in Cambridge, Massachusetts, with a 10-year term. This additional space became available for occupancy on January 1, 2020
Land subject to additional ground leases | ft²	33,526
Massachusetts | Lease Amendment | Sublease agreement with EQRx
Lease Agreements [Line Items]
Lease term	10 years
Lease term, description	In May 2018, the Company executed an amendment to lease an additional 33,526 square feet at 50 Hampshire Street in Cambridge, Massachusetts, with a 10-year term.
Land subject to additional ground leases | ft²	33,526
Massachusetts | Minimum
Lease Agreements [Line Items]
Lease term		1 year
Operating lease, discount rate		950.00%
Massachusetts | Maximum
Lease Agreements [Line Items]
Lease term		10 years
Operating lease, discount rate		1050.00%