Condensed Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
OPERATING ACTIVITIES
Net income	$ 1,405,000	$ 117,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	417,000	567,000
Amortization of finite-lived intangible assets	75,000	75,000
(Recovery) impairment of note receivable	(4,000)	102,000
Stock-based compensation	64,000	88,000
Deferred income tax expense	46,000	41,000
Loss (gain) on marketable securities	28,000	(21,000)
Dividend from marketable securities		(6,000)
Changes in operating assets and liabilities:
(Increase) decrease in accounts receivable, net	(1,000)	111,000
Increase in inventories, net	(591,000)	(237,000)
Decrease (increase) in prepaid expenses and other assets	92,000	(28,000)
Increase (decrease) in accounts payable, accrued compensation and commissions expense and other accrued liabilities	125,000	(128,000)
Net cash provided by operating activities	1,656,000	681,000
INVESTING ACTIVITIES
Purchase of marketable securities		(1,002,000)
Capital expenditures	(324,000)	(131,000)
Proceeds from sale of land		96,000
Other		34,000
Net cash used in investing activities	(324,000)	(1,003,000)
FINANCING ACTIVITIES
(Costs) proceeds from issuance of common stock, net of issuance costs	(28,000)	10,794,000
Proceeds from warrant exercise	927,000
Proceeds from stock option exercise	27,000
Net cash provided by financing activities	926,000	10,794,000
(Decrease) increase in cash and cash equivalents	2,258,000	10,472,000
Cash and cash equivalents at beginning of year	13,250,000	2,778,000
Cash and cash equivalents at end of year	15,508,000	13,250,000
Supplemental Disclosure:
Cash paid for interest	23,000	23,000
Cash paid for income taxes	$ 69,000	$ 41,000