Subsequent events - Additional Information (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Jan. 31, 2022	Dec. 31, 2021
STOPS
Subsequent Event [Line Items]
Non-cancellable purchase commitments			$ 1.9
Subsequent Event | STOPS
Subsequent Event [Line Items]
Non-cancellable purchase commitments	$ 1.9
Subsequent Event | Merck License and Research Collaboration | Merck
Subsequent Event [Line Items]
Milestone payments and royalties receivable		$ 460.0