Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flow from operating activities:
Net loss	$ (12,635)	$ (10,016)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	197	288
Stock-based compensation and 401(k) match	612	542
Fair value adjustment of common stock warrants	(162)	3,434
Amortization of discount on long-term debt	59	0
Changes in:
Inventory	195	0
Prepaid expenses and other current assets	98	49
Accounts payable	659	228
Accrued expenses	814	(85)
Other assets	(111)	0
Other liabilities and accrued interest	39	14
Net cash used in operating activities	(10,235)	(5,546)
Cash flows from investing activities:
Purchase of property and equipment	(120)	(138)
Net cash used in investing activities	(120)	(138)
Cash flows from financing activities:
Proceeds from issuance of long-term debt, net of expenses	9,850	0
Proceeds from exercise of common stock options	1
Proceeds from issuance of securities, net of expenses	0	43,604
Proceeds from exercise of common stock warrants	0	6,713
Repayment of equipment loans and capital lease obligations	(18)	(20)
Net cash provided by financing activities	9,833	50,297
Net increase in cash and cash equivalents	(522)	44,613
Cash and cash equivalents - beginning of period	26,892	10,189
Cash and cash equivalents - end of period	26,370	54,802
Supplementary disclosure of cash flows information:
Interest paid	$ 116	$ 4