Income taxes - Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of uncertain tax benefits
Balance at beginning of the year	$ 297	$ 116	$ 103
Reductions for taxes positions related to prior years	(143)
Additions for taxes positions related to prior years		181	13
Balance at the end of the year	$ 154	$ 297	$ 116