Stockholders' Equity (Deficit) (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of the gain (loss) from the change in fair value of warrants and other financial instruments
Total gain (loss) on change in fair market value of derivatives	$ 6	$ 2,222	$ (6,018)
Committed Equity Financing Facility Warrants [Member]
Summary of the gain (loss) from the change in fair value of warrants and other financial instruments
Total gain (loss) on change in fair market value of derivatives		3	96
Direct Registration Warrants [Member]
Summary of the gain (loss) from the change in fair value of warrants and other financial instruments
Total gain (loss) on change in fair market value of derivatives	6	102	2,093
Excess of value of the Private Placement Warrants at issuance over the net proceeds of the offering [Member]
Summary of the gain (loss) from the change in fair value of warrants and other financial instruments
Total gain (loss) on change in fair market value of derivatives			(4,933)
Gain recognized in connection with warrant exchange agreements [Member]
Summary of the gain (loss) from the change in fair value of warrants and other financial instruments
Total gain (loss) on change in fair market value of derivatives		690
Private Placement Warrants [Member]
Summary of the gain (loss) from the change in fair value of warrants and other financial instruments
Total gain (loss) on change in fair market value of derivatives		$ 1,427	$ (3,274)