CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net loss	$ (1,102)	$ (2,775)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	443	824
Depreciation and amortization	488	304
Amortization of intangible assets	294	309
Amortization of debt discount	19	24
Deferred income taxes	1
Gain on sale of equipment	(18)
Changes in assets and liabilities:
Accounts receivable	(3,520)	49
Inventories	(1,740)	886
Prepaid expenses and other current assets	(163)	(194)
Other non-current assets	(129)	(79)
Accounts payable	125	225
Accrued compensation and benefits	205	187
Accrued expenses and other current liabilities	147	24
Price adjustments and other revenue reserves	4,545
Deferred rent	(110)	(101)
Net cash used in operating activities	(515)	(317)
Cash flows from investing activities:
Acquisition of property and equipment	(293)	(605)
Net cash used in investing activities	(293)	(605)
Cash flows from financing activities:
Proceeds from exercise of stock options and employee stock purchase plan	329	258
Tax withholdings related to net share settlement of restricted stock units	(55)
Proceeds from revolving line of credit	1,500	11,374
Payments on revolving line of credit	(1,500)	(11,283)
Payments on term loan		(1,636)
Net cash provided by (used in )financing activities	274	(1,287)
Effect of exchange rates on cash and equivalents	2	(13)
Net decrease in cash and cash equivalents	(532)	(2,222)
Cash and cash equivalents - beginning of period	30,078	19,719
Cash and cash equivalents - end of period	29,546	17,497
Supplemental disclosures of other cash flow information:
Cash paid for interest expense	137	199
Supplemental disclosures of non-cash investing and financing information:
Purchase of property and equipment included in accounts payable	$ 1,065	$ 219