Cash flow information - Supplemental and Non-cash transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flow information
Interest paid	$ 8	$ 96
Income taxes paid	150	284
Deferred equity offering costs amortized	57	32
Deferred equity offering costs written off	$ 352	$ 59