Leases - Lease Costs and Other Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Lease costs:
Operating lease costs	$ 270	$ 272	$ 764	$ 779
Variable lease costs	18	29	66	84
Total	288	301	830	863
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 257	$ 264	$ 740	$ 759