Commitments and contingencies - Additional Information (Detail) - USD ($) |
Dec. 31, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Loss Contingencies [Line Items] | ||
| Contingent liabilities | $ 0 | $ 0 |
| STOPS | ||
| Loss Contingencies [Line Items] | ||
| Non-cancellable purchase commitments | $ 1,900,000 |