Leases - Components of Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Sub-lease income	$ (25)	$ (26)	$ (87)	$ (80)
Lease cost	139	148	423	451
Operating lease cost, net	114	122	336	371
Sub-lease income	0	(68)	(136)	(204)
Lease cost	0	59	109	180
Restructured lease income, net	0	(9)	(27)	(24)
Total lease cost, net	$ 114	$ 113	$ 309	$ 347