Geographic areas - Disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,695	$ 1,307	$ 4,778	$ 3,853
Total long-lived assets	10,603		10,603		$ 11,827
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	10,106		10,106		11,251
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	951	784	2,461	2,100
Total long-lived assets	497		497		$ 576
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	293	304	1,008	1,197
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	237	70	757	197
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 214	$ 149	$ 552	$ 359