Condensed Consolidated Statements of Cash Flows - Unaudited - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
OPERATING ACTIVITIES
Net income	$ 1,143,000	$ 148,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	315,000	464,000
Amortization of finite-lived intangible assets	56,000	56,000
Recovery of other assets	(4,000)
Stock-based compensation	19,000	22,000
Gain on marketable securities	(183,000)	(21,000)
Deferred income tax provision	28,000	12,000
Changes in operating assets and liabilities:
(Increase) decrease in accounts receivable, net	(712,000)	267,000
Increase in inventories, net	(542,000)	(269,000)
Decrease (increase) in prepaid expenses and other assets	21,000	(148,000)
Increase (decrease) in accounts payable, accrued compensation and commissions and other accrued liabilities	548,000	(345,000)
Net cash provided by operating activities	689,000	186,000
INVESTING ACTIVITIES
Purchase of marketable securities, net	(12,275,000)	(968,000)
Capital expenditures	(232,000)	(20,000)
Net cash used in investing activities	(12,507,000)	(988,000)
FINANCING ACTIVITIES
Proceeds from warrant exercise	927,000
Proceeds from stock option exercise	27,000
Net cash provided by financing activities	954,000
Decrease in cash and cash equivalents	(10,864,000)	(802,000)
Cash and cash equivalents at beginning of period	13,250,000	2,778,000
Cash and cash equivalents at end of period	2,386,000	1,976,000
Supplemental Disclosure:
Cash paid for interest	23,000	23,000
Cash paid for income taxes	$ 45,000	$ 26,000