Income taxes - Income Taxes Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
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%
Permanent differences	(0.10%)
Section 162(m) limitation		10.30%
Changes in valuation allowance	(19.70%)	(31.10%)
Other	(1.20%)	(0.20%)
Effective income tax rate	0.00%	0.00%