CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 539,000	$ 175,000
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of operating lease right-of-use asset	8,000	8,000
Loss from investments in unconsolidated entities, net	139,000	146,000
Distributed earnings from unconsolidated entities	0	31,000
Deferred income taxes	0	(120,000)
Changes in:
Accounts receivable	(482,000)	(40,000)
Income taxes receivable/payable	5,000	179,000
Other current assets	19,000	6,000
Accounts payable and accrued expenses	(4,000)	13,000
Deferred revenue	0	362,000
Operating lease right-of-use liability	(10,000)	(8,000)
Net cash provided by operating activities	214,000	752,000
Cash flows from investing activities:
Advances to unconsolidated entities	(144,000)	(172,000)
Repayments from loans to unconsolidated entities	0	9,000
Capital contributions to unconsolidated entities	0	(36,000)
Principal payments received under sales-type sublease	532,000	216,000
Net cash provided by investing activities	388,000	17,000
Cash flows from financing activities:
Repayment of finance lease obligations	(89,000)	(370,000)
Net cash used in financing activities	(89,000)	(370,000)
Net change in cash and cash equivalents	513,000	399,000
Cash and cash equivalents - beginning of period	2,030,000	1,335,000	$ 1,335,000
Cash and cash equivalents - end of period	2,543,000	1,734,000	$ 2,030,000
Cash paid for:
Interest	$ 2,000	$ 11,000