Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net loss	$ (6,114)	$ (9,409)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	399	514
Stock-based compensation	706	625
Stock-based compensation reversal	0	(270)
Provision for doubtful accounts receivable	(15)	19
Provision for slow-moving and obsolete inventories and valuation reserves	(532)	(644)
Provision for warranties	46	152
Loss on dispositions of property and equipment	4	108
Changes in operating assets and liabilities:
Accounts Receivable	648	2,638
Inventories	(184)	3,334
Prepaid and other assets	(647)	(161)
Accounts payable	1,447	(1,173)
Accrued and other liabilities	391	(433)
Deferred revenue	5	16
Total adjustments	2,268	4,725
Net cash used in operating activities	(3,846)	(4,684)
Cash flows from investing activities:
Acquisitions of property and equipment	(57)	(154)
Proceeds from the sale of property and equipment	240	97
Net cash provided by (used in) investing activities	183	(57)
Cash flows from financing activities:
Proceeds from exercises of stock options and employee stock purchase plan purchases	21	105
Common stock withheld to satisfy income tax withholding on vesting of restricted stock units	60	49
Net cash (used in) provided by financing activities	(39)	56
Effect of exchange rate changes on cash	(5)	(9)
Net decrease in cash and cash equivalents	(3,707)	(4,694)
Cash and cash equivalents, beginning of period	10,761	16,629
Cash and cash equivalents, end of period	7,054	11,935
Classification of cash and cash equivalents:
Cash and cash equivalents, end of period	$ 10,761	$ 16,629