Leases - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended					3 Months Ended			6 Months Ended
	Jun. 30, 2024	Feb. 29, 2024	Dec. 31, 2023	Oct. 31, 2022	Sep. 30, 2021	Sep. 30, 2024	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Jul. 31, 2024
Leases [Line Items]
ROU asset	$ 495		$ 2,187				$ 495		$ 495
Lease liability	9,000						9,000		9,000
Remaining payments contractually due under lease	11,000						11,000		11,000
Operating lease costs							300	$ 2,600	600	$ 5,100
Impairment loss to operating lease right-of-use assets			16,600				0	0	0	0
Cash paid for operating lease							6,200	2,800	10,000	4,900
Variable lease costs							0	$ 500	$ 100	$ 600
Waltham Leases
Leases [Line Items]
Expiration date					Jul. 30, 2030
Operating lease, existence of option to extend					true
Lease, option to extend									The Company has the option to renew the leased space for an additional one time period of five years with written notice from the Company. As of June 30, 2024, the Company has no reasonable certainty that this option to extend will be exercised.
Tenant improvement allowance to be reimbursed	900				$ 3,100		900		$ 900
Lease commencement month and year					2021-09
Additional one time lease period					5 years
New Lease Agreement with BP Bay Colony LLC
Leases [Line Items]
ROU asset					$ 6,000
Lease liability					6,000
Sublease Agreement with AMAG Pharmaceuticals Inc.
Leases [Line Items]
ROU asset					17,300
Lease liability					$ 17,300
Gain on termination of lease	$ 1,800
Lease, termination date	Jun. 30, 2024
Termination fee paid	$ 5,700						$ 5,700		$ 5,700
2022 SOW Under the DMS Agreement
Leases [Line Items]
Lease expiration month and year				2024-12
ROU asset				$ 14,700
Lease liability				14,700
Utilization fee				$ 16,300
Lessee operating lease, lease term including renewal option				2 years 3 months
Reduction to right-of-use asset and lease liability			$ 4,900
2024 SOW Under the DMS Agreement
Leases [Line Items]
Gain on termination of lease		$ 5,600
Termination Agreement with BP Bay Colony LLC | Forecast
Leases [Line Items]
Gain on termination of lease						$ 1,500
Termination Agreement with BP Bay Colony LLC | Subsequent Event
Leases [Line Items]
Termination fee payable											$ 7,000