Restricted cash - Schedule of Collateralized Bank Account of Financial Institution (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt and Equity Securities, FV-NI [Line Items]
Total restricted cash	$ 52,842	$ 45,439
50 Binney Street lease
Debt and Equity Securities, FV-NI [Line Items]
Total restricted cash	40,072	40,072
Assembly Row lease
Debt and Equity Securities, FV-NI [Line Items]
Total restricted cash	2,753	2,753
Embedded lease
Debt and Equity Securities, FV-NI [Line Items]
Total restricted cash	7,632	0
Other
Debt and Equity Securities, FV-NI [Line Items]
Total restricted cash	$ 2,385	$ 2,614