Receivables - Installment Receivables (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Receivables [Abstract]
Installment receivables, current	$ 218,000	$ 704,000
Installment receivables, long-term	734,000	1,105,000
Total Installment Receivables	952,000	1,809,000
Unearned Interest - Current	0	0
Unearned interest, long-term	0	0
Total Unearned Interest	4,156,000	3,516,000
Unearned Interest	0	0
Installment receivables net of unearned interest, current	218,000	704,000
Installment receivables net of unearned interest, long-term	734,000	1,105,000
Total installment receivables net of unearned interest	952,000	1,809,000
Allowance for doubtful accounts, current	0	(325,000)
Allowance for doubtful accounts, long-term	0	(162,000)
Allowance for doubtful accounts	0	(487,000)	$ (1,514,000)
Installment receivables, net	218,000	379,000
Installment receivables, long-term	734,000	943,000
Total installment receivables, net	$ 952,000	$ 1,322,000