Leases - Operating Leases (Details) $ in Thousands	3 Months Ended		12 Months Ended		15 Months Ended
	Mar. 31, 2022 USD ($) ft² item lease	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) ft²	Dec. 31, 2020 ft² lease agreement	Mar. 31, 2022 USD ($) ft²
Lessee, Lease, Description [Line Items]
Number of real estate leases | lease	1
Right-of-use assets	$ 11,888		$ 12,392		$ 11,888
Lease liabilities	$ 18,025				$ 18,025
Weighted-average discount rate	11.00%				11.00%
Lease expense for operating lease payments	$ 1,000	$ 1,000
Cash paid against operating lease liabilities	$ 1,200	$ 1,400
Weighted average remaining term of the operating leases	4 years				4 years
Sublease income					$ 1,200
Maximum
Lessee, Lease, Description [Line Items]
100 basis point change effect on ROU asset	$ 1,000
830 Winter Street, Waltham, MA
Lessee, Lease, Description [Line Items]
Area of space leased | ft²	120,000				120,000
Lessee, Operating Lease, Existence of Option to Extend [true false]	true
Number of additional terms for which lease agreement can be extended | item	2
Operating lease term extension period	5 years				5 years
Number of executed sub-lease spaces | lease				4
Area of executed sublease space | ft²			65,000
Winter Street 930 Waltham MA
Lessee, Lease, Description [Line Items]
Number of executed sub-lease spaces | agreement				4
Area of executed sublease space | ft²				65,000
Minimum rental payments over the remaining term of the sublease	$ 12,500				$ 12,500