Leases - Summary (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2021 USD ($) lease	Sep. 30, 2021 USD ($) lease	Sep. 30, 2020 USD ($)
Leases
Number of finance leases | lease	0	0
Number of operating leases | lease	1	1
Operating lease expense | $	$ 38,000	$ 113,000
Operating lease expense information:
Cash paid for amounts included in measurement of lease liabilities | $	$ 35,000	$ 102,000	$ 90,000
Weighted-average remaining lease term (years)	3 months	3 months
Weighted-average discount rate	15.20%	15.20%