Long-term debt - Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Long-term debt
Term loan payable	$ 30,000	$ 30,000
End of term charge	946	682
Unamortized debt issuance costs	(248)	(367)
Carrying value of term loan	$ 30,698	$ 30,315