Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
OPERATING ACTIVITIES
Net income	$ 27	$ 183
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	115	116
Amortization of finite-lived intangible assets	19	19
Stock-based compensation	78	10
Loss from equity investment in unconsolidated subsidiary	76	39
Unrealized (gain) loss on marketable securities	(127)	325
Deferred income tax expense	29	59
Changes in operating assets and liabilities:
Decrease (increase) in accounts receivable, net	209	(374)
(Increase) decrease in inventories, net	(59)	30
(Increase) decrease in prepaid expenses and other assets	(156)	126
Increase in accounts payable, accrued compensation and commissions and other	191	389
Net cash provided by operating activities	402	922
INVESTING ACTIVITIES
Capital expenditures	(55)	(56)
Net cash used in investing activities	(55)	(56)
FINANCING ACTIVITIES
Proceeds from at-the-market stock sales		3,254
Proceeds from stock option exercise		58
Net cash provided by financing activities		3,312
Increase in cash and cash equivalents	347	4,178
Cash and cash equivalents at beginning of period	18,331	12,453
Cash and cash equivalents at end of period	18,678	16,631
Supplemental Disclosure:
Cash paid for income taxes	27	$ 72
Non-cash subscription agreement (Note C)	$ 2,725