CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Operating activities
Net loss	$ (16,976)	$ (10,741)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	283	402
Stock-based compensation	1,554	1,216
Changes in revaluation of warrant liability	4,387	787
Deferred income taxes	13	0
Non-cash interest expense	0	10
Loss on disposal	56	0
Changes in operating assets and liabilities:
Accounts receivable	(1,424)	2,371
Inventories	(1,341)	(2,937)
Other assets	492	(14)
Accounts payable	(2,151)	(1,172)
Accrued liabilities	990	763
Deferred revenue	76	25
Net cash used in operating activities	(14,041)	(9,290)
Investing activities
Purchases of furniture, equipment and leasehold improvements	(180)	(63)
(Purchases) sales of certain other assets	(13)	2
Maturities of investments	0	287
Net cash provided by (used in) investing activities	(193)	226
Financing activities
Net proceeds from equity incentives	191	226
Net proceeds from public offering	51,171	9,876
Proceeds from warrant exercises	0	17
Proceeds from revolving line of credit	526	175
Payments on debt and landlord provided leasehold incentives	(6,149)	(60)
Net cash provided by financing activities	45,739	10,234
Net increase in cash and cash equivalents	31,505	1,170
Cash and cash equivalents, beginning of period	26,696	25,497
Cash and cash equivalents, end of period	58,201	26,667
Supplemental disclosures:
Cash paid for interest	203	204
Non-cash conversion of preferred stock to common stock	0	9,496
Non-cash settlement of warranty claim	$ 1,272	$ 0