Commitments and contingencies - Lease Contracts (Detail) $ in Thousands		3 Months Ended
	Jul. 28, 2021 USD ($) ft²	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Operating lease expense		$ 3,500	$ 1,900
Operating lease payment		$ 2,900	1,700
Lease weighted-average remaining lease term		15 years 11 months 19 days
Lease weighted average discount rate		6.39%
Operating lease area | ft²	21,000
Anticipated receipt of the tenant incentive		$ 17,628
Change in right-of-use asset		10,400	1,400
Change in operating lease liabilities.		11,600	1,100
Non-cancelable operating lease payments in 2022		9,474
Future minimum payments		$ 147,215
South San Francisco, California [Member]
Operating lease term	7 years
Operating lease security deposit with the lessor	$ 200
Initial annual base rent	$ 1,700
Operating lease base rent annual percentage increase	3.00%
Future minimum payments			$ 13,100