Exhibit 99.1

                            Explanation of Responses


(1)  The general partner of Oracle Institutional Partners, L.P. ("Oracle
     Institutional") is Oracle Associates, LLC ("Oracle Associates"). Mr. Larry
     N. Feinberg ("Mr. Feinberg") serves as the senior managing member of Oracle
     Associates. Any further transactions in securities of the issuer required
     to be reported by Oracle Institutional will be reported in joint filings
     with Mr. Feinberg on Form 4.

(2)  The Warrants are exercisable in whole or in part, at any time or from time
     to time (beginning on November 7, 2007), at the option of the holder until
     November 10, 2013, at an exercise price of $3.50 per share, subject to
     adjustment.

(3)  Each share of Preferred Stock is convertible in whole or in part, at any
     time or from time to time, at the option of the holder into 3,333.33 shares
     of Common Stock, at an exercise price of $3.00 per share, subject to
     adjustment.