CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - UNAUDITED - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
OPERATING ACTIVITIES
Net income	$ 193	$ 111
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	104	167
Amortization of finite-lived intangible assets	18	20
Recovery of note receivable	(4)
Stock-based compensation	7	7
Gain on marketable securities	(12)
Deferred income tax provision	(7)	(7)
Changes in operating assets and liabilities:
(Increase) decrease in accounts receivable, net	(259)	318
Increase in inventories, net	(133)	(412)
Decrease (increase) in prepaid expenses and other assets	72	(95)
Increase in accounts payable, accrued compensation and commissions and other accrued liabilities	179	110
Net cash provided by operating activities	158	219
INVESTING ACTIVITIES
Purchase of marketable securities	(11,775)	(1,002)
Capital expenditures	(172)	(6)
Net cash used in investing activities	(11,947)	(1,008)
FINANCING ACTIVITIES
Proceeds from issuance of common stock	22
Net cash provided by financing activities	22
Decrease in cash and cash equivalents	(11,767)	(789)
Cash and cash equivalents at beginning of period	13,250	2,778
Cash and cash equivalents at end of period	1,483	1,989
Supplemental Disclosure:
Cash paid for interest	11
Cash paid for income taxes	$ 9	$ 18