Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating activities:
Net loss	$ (2,011)	$ (12,004)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,447	2,375
Provision for doubtful accounts and other adjustments to accounts receivable	(289)	347
Provision for excess and obsolete inventory	34	38
Loss on disposal of fixed assets	1
Non-cash compensation related to stock options, ESPP and restricted stock	1,627	3,095
Change in operating accounts:
Accounts receivable	500	(139)
Income tax receivable	697	(2)
Inventories	(1)	(36)
Prepaid expenses and other assets	(151)	(240)
Accounts payable and accrued liabilities	(1,337)	(1,082)
Deferred revenue	(848)	267
Net cash used in operating activities	(331)	(7,381)
Investing activities:
Capital expenditures	(131)	(84)
Sales (purchases) of short-term investments	(1,199)	877
Net cash (used in) provided by investing activities	(1,330)	793
Financing activities:
Cash received from issuance of common stock, net of offering costs		5,291
Cash received from stock sale under employee stock purchase plan	17	21
Cash received from exercise of stock options	10	6
Net cash provided by financing activities	27	5,318
Net decrease in cash and cash equivalents	(1,634)	(1,270)
Cash and cash equivalents, beginning of period	10,165	11,763
Cash and cash equivalents, end of period	8,531	10,493
Supplemental disclosures of cash flow information:
Cash paid for income taxes	16	$ 61
Change in unrealized gain on short-term investments	$ 1