Leases - Additional Information (Detail) $ in Thousands	1 Months Ended		12 Months Ended
	Jan. 31, 2019 USD ($) ft²	Jan. 31, 2018 USD ($) ft²	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Nov. 30, 2018 USD ($)
Commitment And Contingencies [Line Items]
Future minimum rent commitment			$ 5,331
Future minimum lease commitment			852
Rent expense			$ 2,562	$ 2,500	$ 2,524
Cambridge, Massachusetts [Member] | Lab Equipment [Member]
Commitment And Contingencies [Line Items]
Lease term of contract			48 months
Future minimum lease commitment						$ 900
Lab Space [Member] | Cambridge, Massachusetts [Member]
Commitment And Contingencies [Line Items]
Area of lease agreement | ft²		9,500
Lease term		5 years
Lessee, Operating Lease, Existence of Option to Extend [true false]		true
Lease renewal term		2 years
Future minimum rent commitment		$ 1,900
Office Space [Member] | Cambridge, Massachusetts [Member]
Commitment And Contingencies [Line Items]
Area of lease agreement | ft²	5,000	16,000
Future minimum rent commitment	$ 2,000	$ 1,500
Lease expiration period	2025-10	2022-02
Minimum [Member]
Commitment And Contingencies [Line Items]
Remaining lease terms			1 year
Maximum [Member]
Commitment And Contingencies [Line Items]
Remaining lease terms			6 years