Fair Value of Assets and Liabilities (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Assets and liabilities measured at fair value on a recurring basis
Derivative warrant liability	$ 14,584,818	$ 35,473,230	$ 10,647,190
Level 1 [Member]
Assets and liabilities measured at fair value on a recurring basis
Derivative warrant liability
Level 2 [Member]
Assets and liabilities measured at fair value on a recurring basis
Derivative warrant liability	14,584,818	35,473,230
Level 3 [Member]
Assets and liabilities measured at fair value on a recurring basis
Derivative warrant liability