Condensed Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
OPERATING ACTIVITIES
Net income	$ 7,016,000	$ 1,405,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	418,000	417,000
Amortization of finite-lived intangible assets	75,000	75,000
Loss from equity investment in unconsolidated subsidiary	16,000
Recovery of note receivable		(4,000)
Stock-based compensation	112,000	64,000
Deferred income tax (benefit) expense	(3,180,000)	46,000
(Gain) loss on marketable securities	(206,000)	28,000
Changes in operating assets and liabilities:
Increase in accounts receivable, net	(1,051,000)	(1,000)
Increase in inventories, net	(1,550,000)	(591,000)
(Increase) decrease in prepaid expenses and other assets	(225,000)	92,000
Increase in accounts payable, accrued compensation and commissions expense and other accrued liabilities	1,241,000	125,000
Net cash provided by operating activities	2,666,000	1,656,000
INVESTING ACTIVITIES
Purchase of marketable securities	(5,050,000)
Equity investment in unconsoldiated subsidiary	(3,350,000)
Capital expenditures	(1,163,000)	(324,000)
Proceeds from sale of marketable securities	3,400,000
Net cash used in investing activities	(6,163,000)	(324,000)
FINANCING ACTIVITIES
Costs from issuance of common stock		(28,000)
Proceeds from warrant exercise		927,000
Proceeds from stock option exercise	442,000	27,000
Net cash provided by financing activities	442,000	926,000
(Decrease) increase in cash and cash equivalents	(3,055,000)	2,258,000
Cash and cash equivalents at beginning of year	15,508,000	13,250,000
Cash and cash equivalents at end of year	12,453,000	15,508,000
Supplemental Disclosure:
Cash paid for interest	6,000	23,000
Cash paid for income taxes	86,000	$ 69,000
Non-Cash Disclosure:
Right-of-use assets offset by operating lease liabilities	$ 331,000