Income taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current
Federal	$ 0	$ 0	$ 0
State	324	45	183
Foreign	3,494	2,241	1,149
Total current income tax expense	3,818	2,286	1,332
Deferred:
Federal	0	0	0
State	0	0	0
Foreign	(165)	0	(149)
Total deferred income tax benefit	(165)	0	(149)
Total provision for income taxes	$ 3,653	$ 2,286	$ 1,183