Leases - Additional Information (Details)	1 Months Ended		12 Months Ended
	Nov. 30, 2021 USD ($) Contract	Jul. 31, 2017	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Lessee Lease Description [Line Items]
Right-of-use assets			$ 31,945,000	$ 13,229,000
Liabilities under lease			32,111,000
Watertown Lease
Lessee Lease Description [Line Items]
Right-of-use assets			16,700,000
Liabilities under lease			15,100,000
Construction costs			1,500,000
Tenant improvements	$ 2,600,000		$ 0
Watertown Lease | Office and Laboratory Space
Lessee Lease Description [Line Items]
Lease commencement date		2018-04
Lessee operating lease, description			In July 2017, the Company entered into a lease of office and laboratory space for its headquarters in Watertown, Massachusetts, or the Watertown Lease. The Watertown Lease had a non-cancelable term of ten years with an option to extend for one additional five-year period and is subject to rent escalation throughout the term. Additionally, the Watertown Lease required the Company to provide collateral, which was recorded as restricted cash on the consolidated balance sheets. The Watertown Lease commenced in April 2018.
Watertown Lease | Newly Leased Space
Lessee Lease Description [Line Items]
Right-of-use assets	20,100,000
Liabilities under lease	$ 20,100,000
Amended lease commencement date	2022-01
Rent commencing after lease commencement period	2 months
Amended lease termination date	2032-01
Lease term of amended lease terminate period	10 years
Tenant improvements	$ 2,600,000
Extend lease term of amended lease period	5 years
Restricted cash	$ 3,300,000
Number of amended lease separate contracts | Contract	2
Undiscounted lease payments	$ 62,100,000