Fair Value of Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended			3 Months Ended				6 Months Ended			3 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2012	Jun. 30, 2012 Series C-1 Preferred Stock [Member]	Jun. 30, 2011 Series C-1 Preferred Stock [Member]	Jun. 30, 2012 Embedded Derivative [Member]	Mar. 31, 2012 Embedded Derivative [Member]	Jun. 30, 2011 Embedded Derivative [Member]	Mar. 31, 2011 Embedded Derivative [Member]	Jun. 30, 2012 Embedded Derivative [Member]	Jun. 30, 2012 Embedded Derivative [Member] Series C-1 Preferred Stock [Member]	Jun. 30, 2011 Embedded Derivative [Member] Series C-1 Preferred Stock [Member]	Jun. 30, 2012 Warrant Derivative [Member]	Mar. 31, 2012 Warrant Derivative [Member]	Jun. 30, 2011 Warrant Derivative [Member]	Mar. 31, 2011 Warrant Derivative [Member]
Liabilities measured at estimated fair value using unobservable inputs
Beginning balance	$ 9,417	$ 15,270	$ 12,059	$ 6,102	$ 15,270			$ 3,242	$ 3,680	$ 5,257	$ 5,170	$ 3,680			$ 6,175	$ 11,590	$ 6,802	$ 932
Adjustments to estimated fair value	4,485	(5,954)	(5,382)	6,029				916	(539)	(924)	159				3,569	(5,415)	(4,458)	(5,870)
Accrued dividends payable in Series C-1 Preferred					(96)	101	(72)					(96)	101	(72)
Ending balance	$ 13,806	$ 9,417	$ 6,677	$ 12,059	$ 13,806			$ 4,062	$ 3,242	$ 4,333	$ 5,257	$ 4,062			$ 9,744	$ 6,175	$ 2,344	$ 6,802