Income taxes - Narrative (Detail)	12 Months Ended
	Dec. 31, 2022 USD ($)
Components Of Income Tax Expense Benefit [Line Items]
Approximately valuation allowance increased	$ 69,700,000
Income tax examination, penalties and interest accrued	0
Capitalized research and development expense	$ 232,100,000
Research Tax Credit Carryforward
Components Of Income Tax Expense Benefit [Line Items]
Limitations on use of net operating losses and tax credit carryforwards, percentage	50.00%
Limitations on use of net operating losses and tax credit carryforwards, period	3 years
U.S.
Components Of Income Tax Expense Benefit [Line Items]
Operating loss carryforwards	$ 96,100,000
U.S. | Research Tax Credit Carryforward
Components Of Income Tax Expense Benefit [Line Items]
Tax credit carryforward amount	8,100,000
State and Local Jurisdiction
Components Of Income Tax Expense Benefit [Line Items]
Operating loss carryforwards	113,500,000
State and Local Jurisdiction | Research Tax Credit Carryforward
Components Of Income Tax Expense Benefit [Line Items]
Tax credit carryforward amount	$ 3,300,000