Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Operating activities:
Net loss	$ (45,240)	$ (46,743)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	5,579	4,538
Restructuring	201	0
Depreciation and amortization	1,395	1,172
Amortization of debt issuance costs and non-cash interest	422	1,898
Change in fair value of warrant liabilities	2,780	3,611
Change in fair value of embedded derivatives	(912)	(166)
Changes in operating assets and liabilities:
Trade accounts receivable	(518)	(591)
Inventory, net	797	2,546
Prepaid expenses and other current assets	482	(469)
Other assets	614	(286)
Accounts payable and accrued expenses	205	(756)
Restructuring liabilities	6	0
Deferred revenue	0	(8,462)
Net cash used in operating activities	(34,189)	(43,708)
Investing activities:
Purchases of property and equipment	(785)	(255)
Net cash used in investing activities	(785)	(255)
Financing activities:
Proceeds from revolving credit facility	0	9,900
Payments on borrowings of debt	0	(40,051)
Proceeds from exercise of common stock options	0	27
Proceeds from issuance of common stock and common stock warrants	11,098	67,114
Net cash provided by financing activities	11,098	36,990
Net decrease in cash and cash equivalents	(23,876)	(6,973)
Cash and cash equivalents at beginning of period	41,228	56,525
Cash and cash equivalents at end of period	$ 17,352	$ 49,552