Income taxes - Schedule of effective income tax rate reconciliation (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income tax benefit computed at federal statutory tax rate	21.00%	21.00%
State tax—net of federal	6.40%	4.20%
Federal credits	3.00%	3.50%
State credits	1.30%	1.40%
Other permanent differences	(1.00%)	(0.20%)
Withholding tax	0.00%	(0.90%)
Stock-based compensation	(4.20%)	(2.80%)
Valuation allowance	(26.60%)	(27.20%)
Total	(0.10%)	(1.00%)