CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Operating activities:
Net loss	$ (13,402)	$ (16,507)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,119	2,218
Loss on disposal of fixed assets		161
Provision for doubtful accounts and other adjustments to accounts receivable	366	585
Provision for excess and obsolete inventory	54	33
Non-cash compensation related to stock options, ESPP and restricted stock	1,926	2,154
Change in operating accounts:
Accounts receivable	130	(445)
Income tax receivable	2	606
Inventories	(8)	40
Prepaid expenses and other assets	(375)	(383)
Accounts payable and accrued liabilities	568	(2,445)
Net cash used in operating activities	(8,620)	(13,983)
Investing activities:
Capital expenditures	(140)	(78)
Sales (purchases) of short-term investments	(973)	18,239
Net cash provided by (used in) investing activities	(1,113)	18,161
Financing activities:
Cash received from stock sale for employee stock purchase plan	21	55
Cash received from exercise of stock options		11
Repurchase of common stock		(753)
Net cash provided by (used in) financing activities	21	(687)
Net increase (decrease) in cash and cash equivalents	(9,712)	3,491
Cash and cash equivalents, beginning of period	18,873	7,475
Cash and cash equivalents, end of period	9,161	10,966
Supplemental disclosures of cash flow information:
Cash paid for income taxes	$ 77	$ 100