Leases - Additional Information (Details) - USD ($)	1 Months Ended				3 Months Ended	12 Months Ended
	Nov. 30, 2021	Sep. 30, 2019	Mar. 31, 2018	Jul. 31, 2017	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Jan. 31, 2022
Lessee, Lease, Description [Line Items]
Operating leases, option to extend		option to extend for up to two five-year periods.
Operating lease liability					$ 1,503,000	$ 1,503,000
Operating lease right-of-use assets					1,254,000	1,254,000	$ 7,480,000
201 Brookline Avenue Lease [Member]
Lessee, Lease, Description [Line Items]
Operating leases, non-cancelable term		10 years
Operating leases, option to extend		true
Annual rent payable		$ 5,100,000
Percentage of increase in annual rent payable		3.00%
Proceeds from line of credit		$ 1,700,000
Tenant improvements allowance		$ 12,700,000
201 Brookline Avenue Lease [Member] | Letter of Credit [Member] | Subsequent Event [Member]
Lessee, Lease, Description [Line Items]
Additional letter of credit								$ 1,700,000
100 Binney Street in Cambridge [Member]
Lessee, Lease, Description [Line Items]
Operating leases, non-cancelable term				8 years
Operating leases, option to extend				option to extend for one additional three-year period.
Operating leases, option to extend				true
Operating lease liability			$ 9,500,000
Operating lease right-of-use assets			9,800,000
Upfront payments for rent and tenant improvements			300,000
Tenant obligation payments for leasehold improvements						$ 0	$ 0
Annual rent payable			$ 1,700,000
Percentage of increase in annual rent payable			3.00%
Minimum rent payments to be paid over original term			$ 15,600,000
Letter of credit to provide for amount that collateralized with cash			$ 600,000
Lease termination agreement month and year	2021-11
Lease terminate option description						The lease termination agreement is a modification of the original lease agreement that provides for, among other things, the acceleration of the expiration of the original term of the lease from June 30, 2026 to an earlier lease termination date, for which the earlier date shall be no later than October 15, 2022.
Reduction of operating lease right-of-use asset					(5,200,000)
Reduction of operating lease liability					$ (5,300,000)
100 Binney Street in Cambridge [Member] | Minimum [Member]
Lessee, Lease, Description [Line Items]
Additional extension period				1 year
Lease expiration date	Oct. 15, 2022
100 Binney Street in Cambridge [Member] | Maximum [Member]
Lessee, Lease, Description [Line Items]
Additional extension period				3 years
Lease expiration date	Jun. 30, 2026
100 Binney Street in Cambridge [Member] | Letter of Credit [Member]
Lessee, Lease, Description [Line Items]
Letter of credit to provide for amount that collateralized with cash						$ 600,000