Warrant Liabilities

9 Months Ended

Sep. 30, 2012

Warrant Liabilities [Abstract]

Warrant Liabilities

6. Warrant Liabilities

Liabilities measured at market value on a recurring basis include warrant liabilities resulting from the Company's past equity financings, including the underwritten public offering that closed on August 1, 2011.  In accordance with ASC 815-40, Derivatives and Hedging – Contracts in Entity's Own Equity ("ASC 815-40"), the warrant liabilities are being marked to market until they are completely settled.  The warrants are valued using the Black-Scholes method, using assumptions consistent with our application of ASC 505-50, Equity-Based Payments to Non-Employees ("ASC 505-50").  The gain or loss resulting from the marked to market calculation is shown on the Consolidated Statements of Operations as gain (loss) on warrant derivative liability. The Company recognized a gain of $6.4 million and $4.3 million for the three-month periods ended September 30, 2012 and 2011, respectively, and a gain (loss) of ($6.0 million) and $5.5 million for the nine-month periods ended September 30, 2012 and 2011, respectively.