Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Operating activities:
Net loss	$ (27,461)	$ (38,161)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	2,794	2,183
Depreciation and amortization	790	791
Amortization of debt issuance costs and non-cash interest	797	782
Change in fair value of warrant liability	42	0
Change in fair value of embedded derivatives	(368)	0
Changes in operating assets and liabilities:
Trade accounts receivable	19	1,256
Inventory, net	1,237	(263)
Prepaid expenses and other current assets	(260)	(104)
Other assets	(426)	58
Accounts payable and accrued expenses	1,830	(901)
Deferred rent	2	(30)
Deferred revenue	(8,462)	(6,118)
Net cash used in operating activities	(29,466)	(40,507)
Investing activities:
Purchases of property and equipment	(291)	(366)
Net cash used in investing activities	(291)	(366)
Financing activities:
Proceeds from revolving credit facility	9,899	4,242
Payments on borrowings of debt	(15,040)	(4,883)
Proceeds from exercise of common stock options	2	14
Proceeds from issuance of common stock	345	0
Net cash used in financing activities	(4,794)	(627)
Net decrease in cash and cash equivalents	(34,551)	(41,500)
Cash and cash equivalents at beginning of period	56,525	49,172
Cash and cash equivalents at end of period	$ 21,974	$ 7,672