Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net loss	$ (2,865)	$ (2,390)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	105	151
Stock-based compensation	543	195
Provision for doubtful accounts receivable	26	(22)
Provision for slow-moving and obsolete inventories and valuation reserves	(836)	(487)
Provision for warranties	101	7
Amortization of loan origination fees	(20)	0
Gain on dispositions of property and equipment	(1)	(19)
Changes in operating assets and liabilities:
Accounts receivable	(210)	66
Inventories	643	597
Prepaid and other assets	459	(274)
Accounts payable	(1,329)	1,398
Accrued and other liabilities	(195)	13
Deferred revenue	(17)	22
Total adjustments	(691)	1,647
Net cash used in operating activities	(3,556)	(743)
Cash flows from investing activities:
Acquisitions of property and equipment	(5)	(57)
Proceeds from the sale of property and equipment	1	244
Net cash (used in) provided by investing activities	(4)	187
Cash flows from financing activities:
Common stock withheld to satisfy income tax withholding on vesting of restricted stock units	(111)	(32)
Principal payments under finance lease obligations	(1)	0
Proceeds from convertible notes	1,660	0
Net repayments on credit line borrowings	(462)	0
Net cash provided by (used in) financing activities	1,086	(32)
Effect of exchange rate changes on cash	0	(1)
Net decrease in cash and cash equivalents	(2,474)	(589)
Cash and cash equivalents, beginning of period	6,335	10,761
Cash and cash equivalents, end of period	3,861	10,172
Classification of cash and cash equivalents:
Cash and cash equivalents, end of period	$ 6,335	$ 10,761