Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating leases
Operating lease expense	$ 152	$ 120	$ 458	$ 359
Variable lease expense	51	5	145	139
Operating lease expense	203	125	603	498
Short-term lease rent expense	63	63	188	191
Total expense	$ 266	$ 188	$ 791	$ 689