Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
OPERATING ACTIVITIES
Net income	$ 183	$ 582
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	116	101
Amortization of finite-lived intangible assets	19	18
Stock-based compensation	10	6
Loss from equity investment in unconsolidated subsidiary	39
Loss (gain) on marketable securities	325	(77)
Deferred income tax expense	59	13
Changes in operating assets and liabilities:
Increase in accounts receivable, net	(374)	(1,005)
Decrease (increase) in inventories, net	30	(707)
Decrease (increase) in prepaid expenses and other assets	126	(52)
Increase in accounts payable, accrued compensation and commissions and other accrued liabilities	389	1,243
Net cash provided by operating activities	922	122
INVESTING ACTIVITIES
Purchase of marketable securities, net		(5,000)
Capital expenditures	(56)	(403)
Net cash used in investing activities	(56)	(5,403)
FINANCING ACTIVITIES
Proceeds from at-the-market stock sales	3,254
Proceeds from stock option exercise	58	71
Net cash provided by financing activities	3,312	71
Increase (decrease) in cash and cash equivalents	4,178	(5,210)
Cash and cash equivalents at beginning of period	12,453	15,508
Cash and cash equivalents at end of period	16,631	10,298
Supplemental Disclosure:
Cash paid for interest	6	6
Cash paid for income taxes	$ 72	$ 10