Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Operating activities:
Net loss	$ (10)	$ (5,167)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	495	872
Provision for doubtful accounts and other adjustments to accounts receivable	12	72
Provision for excess and obsolete inventory	5	22
Non-cash compensation related to stock options, ESPP and restricted stock	576	717
Change in operating accounts:
Accounts receivable	606	449
Income tax receivable	673
Inventories	5	(22)
Prepaid expenses and other assets	62	136
Accounts payable and accrued liabilities	(522)	(414)
Deferred revenue	(1,167)	(263)
Net cash provided by (used in) operating activities	735	(3,598)
Investing activities:
Capital expenditures	(21)	(15)
Sales (purchases) of short-term investments	(919)	453
Net cash provided by (used in) investing activities	(940)	438
Financing activities:
Cash received from stock sale for employee stock purchase plan	8	11
Cash received from exercise of stock options	9	6
Net cash provided by financing activities	17	17
Net decrease in cash and cash equivalents	(188)	(3,143)
Cash and cash equivalents, beginning of period	10,165	11,763
Cash and cash equivalents, end of period	9,977	8,620
Supplemental disclosures of cash flow information:
Cash paid for income taxes	$ 6	$ 15