Preferred Stock Warrants

At September 30, 2011, the outstanding warrants to purchase the Company’s Series C and Series D preferred stock which were issued in connection with certain financing arrangements and amendments to existing financing arrangements were expired unexercised in connection with the Merger. Information relating to these warrants at December 31, 2010 is summarized as follows:

Warrant Liability

The warrants issued in conjunction with the 2008 Loan and Security Agreement (see Note 7) are issuable for Series C preferred stock. The warrants issued in connection with the 2009 Convertible Debt (see Note 7) and the Series D Preferred Stock (see Note 8) are issuable for Series D preferred stock. Both the Series C and Series D preferred stock are considered contingently redeemable based on the stockholders’ right to redeem the shares on or after January 7, 2015. In accordance with Accounting Standards Codification on Distinguishing Liabilities from Equity, since the warrants are indexed to contingently redeemable securities of the Company, they are classified as liabilities upon issuance. As liability classified derivative financial instruments, the warrants are initially and subsequently required to be measured at their fair values as defined in Accounting Standards Codification on Fair Value Measurement.

The change in fair value of the warrants between each reporting period is recorded in the statements of operations and was estimated by the Company using a binomial lattice valuation model. The following assumptions were incorporated into the valuations during the nine months ended September 30, 2011 and 2010:

The Company recorded income (expense) of $0 and $139,157 for the three months and $62,305 and $(77,695) for the nine months ended September 30, 2011 and 2010, respectively, as a result of the change in the fair value of warrant liability between reporting periods which was recorded in other income (expense) on the consolidated condensed statements of operations. The total balance of the warrant liability was as of September 30, 2011 of $2,607,510 was forfeited in accordance with the Merger.