Lease - Components of lease expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases
Operating lease cost	$ 1,225	$ 1,225
Variable lease cost	982	959
Total lease costs	2,207	2,184
Finance lease cost
Amortization of right of use asset	$ 85	$ 85
Finance Lease, Right-of-Use Asset, Statement of Financial Position	Other non-current assets	Other non-current assets
Interest on lease liability	$ 6	$ 12