Commitments and Contingencies - Components of lease expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Operating lease costs:
Operating lease rental expense	$ 330	$ 309	$ 993	$ 1,362
Other income	(340)	(305)	(999)	(881)
Total operating lease costs	(10)	4	(6)	481
Finance lease costs:
Amortization of right-of-use assets	1	2	5	6
Total finance lease costs	$ 1	$ 2	$ 5	$ 6