Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Operating activities:
Net loss	$ (12,004)	$ (26,451)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,375	3,110
Long-lived assets write-off due to restructuring		1,011
Provision for doubtful accounts and other adjustments to accounts receivable	347	459
Provision for excess and obsolete inventory	38	62
Non-cash compensation related to stock options, ESPP and restricted stock	3,095	2,747
Deferred income taxes	(2)
Change in operating accounts:
Accounts receivable	(139)	1,479
Income tax receivable		1
Inventories	(36)	(48)
Prepaid expenses and other assets	(240)	(335)
Accounts payable and accrued liabilities	(1,082)	4,010
Deferred revenue	267	593
Net cash used in operating activities	(7,381)	(13,362)
Investing activities:
Capital expenditures	(84)	(820)
Sales of short-term investments	877	6,136
Net cash provided by investing activities	793	5,316
Financing activities:
Cash from issuance of common stock, net of offering costs	5,291
Cash received from stock sale for employee stock purchase plan	21	36
Cash received from exercise of stock options	6
Net cash provided by financing activities	5,318	36
Net decrease in cash and cash equivalents	(1,270)	(8,010)
Cash and cash equivalents, beginning of period	11,763	18,873
Cash and cash equivalents, end of period	10,493	10,863
Supplemental disclosures of cash flow information:
Cash paid for income taxes	$ 61	$ 163