Income taxes - Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current:
Federal	$ 0	$ 6	$ 0
State	(456)	(154)	(217)
Foreign	(3,799)	(1,894)	(638)
Total current provision	(4,255)	(2,042)	(855)
Deferred:
Federal	(130)	268	487
State	80	170	1,145
Foreign	2,026	2,517	4,012
Total deferred benefit	1,976	2,955	5,644
Total income tax (provision) benefit	$ (2,279)	$ 913	$ 4,789