Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Operating activities:
Net loss	$ (1,241)	$ (10,862)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	970	1,676
Provision for doubtful accounts and other adjustments to accounts receivable	(291)	369
Provision for excess and obsolete inventory	31	34
Non-cash compensation related to stock options, ESPP and restricted stock	1,099	2,563
Change in operating accounts:
Accounts receivable	(90)	(195)
Income tax receivable	664	(3)
Inventories		(36)
Prepaid expenses and other assets	(295)	(550)
Accounts payable and accrued liabilities	(968)	(1,193)
Deferred revenue	(1,385)	(345)
Net cash used in operating activities	(1,506)	(8,542)
Investing activities:
Capital expenditures	(63)	(61)
Sales (purchases) of short-term investments	(1,440)	1,859
Net cash (used in) provided by investing activities	(1,503)	1,798
Financing activities:
Cash received from stock sale under employee stock purchase plan	8	11
Cash received from exercise of stock options	10	6
Net cash provided by financing activities	18	17
Net decrease in cash and cash equivalents	(2,991)	(6,727)
Cash and cash equivalents, beginning of period	10,165	11,763
Cash and cash equivalents, end of period	7,174	5,036
Supplemental disclosures of cash flow information:
Cash paid for income taxes	$ 12	$ 42