Accounts payable and accrued liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Payables and Accruals [Abstract]
Trade accounts payable	$ 852	$ 2,398
Research and development accruals	2,719	1,433
Professional fee accruals	447	809
Payroll accruals	2,844	2,314
Site consolidation accrual	0	137
Other accrued liabilities	51	144
Total accounts payable and accrued liabilities	$ 6,913	$ 7,235