Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net loss	$ (7,636)	$ (5,905)
Loss from discontinued operations	0	(12)
Loss from continuing operations	(7,636)	(5,893)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	348	336
Stock-based compensation	433	640
Stock-based compensation reversal	(270)	0
Provision for doubtful accounts receivable	1	(29)
Provision for slow-moving and obsolete inventories and valuation reserves	(271)	167
Provision for warranties	44	46
Loss on dispositions of property and equipment	104	1
Changes in operating assets and liabilities:
Accounts Receivable	2,180	4,952
Inventories	1,839	(7,029)
Prepaid and other assets	(122)	(955)
Accounts payable	(175)	176
Accrued and other liabilities	359	(595)
Deferred revenue	18	(26)
Total adjustments	4,488	(2,316)
Net cash used in operating activities	(3,148)	(8,209)
Cash flows from investing activities:
Acquisitions of property and equipment	(115)	(1,047)
Proceeds from the sale of property and equipment	72	0
Net cash used in investing activities	(43)	(1,047)
Cash flows from financing activities:
Proceeds from exercises of stock options and employee stock purchase plan purchases	106	386
Common stock withheld in lieu of income tax withholding on vesting of restricted stock units	50	0
Common stock withheld to satisfy exercise price and income tax withholding on option exercises	0	(309)
Net cash provided by financing activities	56	77
Effect of exchange rate changes on cash	(7)	(8)
Net cash used in continuing operations	(3,142)	(9,187)
Cash flows of discontinued operations:
Operating cash flows, net	0	(12)
Net cash used in discontinued operations	0	(12)
Net decrease in cash and cash equivalents	(3,142)	(9,199)
Cash and cash equivalents, beginning of period	16,629	34,640
Cash and cash equivalents, end of period	13,487	25,441
Classification of cash and cash equivalents:
Cash and cash equivalents	13,145	25,099
Restricted cash held	342	342
Cash and cash equivalents, end of period	$ 16,629	$ 34,640