Derivative Instruments (Details 1) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Changes in derivative warrant liability
Balance at beginning of year	$ 35,473,230	$ 10,647,190
Increase (decrease) in the fair value of the warrants	(17,479,674)	26,065,579
Reduction in derivative liability due to exercise of warrants	(3,408,738)	(1,239,539)
Balance at end of year	$ 14,584,818	$ 35,473,230

The amount of net gains and losses recognized in income during the period on derivative instruments designated and qualifying as hedging instruments in fair value hedges and related hedged items designated and qualifying in fair value hedges, on derivative instruments designated and qualifying as hedging instruments in cash flow hedges, and on derivative instruments not designated as hedging instruments.

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Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be extinguished or otherwise disposed of within a year or the normal operating cycle, if longer, net of the effects of master netting arrangements.

+ References

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+ Details