Income taxes - Effective Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Federal tax expense	21.00%	21.00%	21.00%
State taxes, net of federal benefit	0.49%	0.50%	1.24%
Foreign rate differential	(0.28%)	(1.40%)	(0.33%)
Withholding taxes	(2.43%)	(1.77%)	(0.60%)
Nondeductible compensation	(6.18%)	(10.20%)	(2.52%)
Stock-based compensation	(9.48%)	(1.84%)	(3.18%)
Change in valuation allowance	(16.40%)	(18.33%)	(21.41%)
Research and development credits	7.57%	7.94%	4.69%
Nontaxable dividends	0.00%	1.31%	0.00%
Other	0.34%	(0.73%)	(0.40%)
Effective tax rate	(5.37%)	(3.52%)	(1.51%)