Leases - Supplemental Balance Sheet Information (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Operating leases
Operating lease right-of-use assets	$ 5,494,000	$ 6,605,000
Operating lease liabilities - current	1,109,000	1,200,000
Operating lease liabilities - long-term	4,899,000	5,940,000
Total operating lease liabilities	6,008,000	7,140,000
Finance leases
Property and equipment, at cost	8,663,000	8,663,000
Accumulated depreciation	(4,624,000)	(3,297,000)
Property and equipment, net	4,039,000	5,366,000
Finance lease liabilities - current	54,000	2,316,000
Finance lease liabilities - long-term	44,000	96,000
Obligations under finance leases	$ 98,000	$ 2,412,000
Weighted average remaining lease term:
Operating leases	5 years 7 months 6 days	6 years 3 months 18 days
Finance leases	1 year 7 months 6 days	9 months 18 days
Weighted average discount rate:
Operating leases	5.04%	5.04%
Finance leases	5.00%	4.67%