Income taxes - Income Taxes Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of effect of applying the federal statutory rate to the net loss and the effective income tax rate
Statutory federal income tax rate	21.00%	21.00%	21.00%
Earnings in jurisdictions taxed at rates different from the statutory U.S. federal tax rate		(0.10%)	0.20%
Permanent differences	(0.60%)		1.70%
Section 162(m) limitation	(2.50%)
In-process research and development	(13.50%)
Changes in valuation allowance	3.70%	18.20%	22.50%
Other	(0.70%)	(2.70%)	(0.40%)
Effective income tax rate	0.00%	0.00%	0.00%