Exhibit 99.1 - Explanation of Responses


(1) Warburg Pincus Private Equity VIII, L.P., a Delaware limited partnership
("WP VIII"), converted 49,473.38 shares of Series A Convertible Preferred Stock
on January 2, 2009, at a fixed initial conversion rate of 10.194210419 shares of
Common Stock per share of Series A Convertible Preferred Stock, resulting in the
issuance to WP VIII of 504,342 shares of Common Stock. On the same day, WP VIII
transferred all 504,342 shares of Common Stock to Ryan Craig, a director of the
issuer, which shares were earned as compensation for past services rendered as a
WP VIII representative to the issuer's board of directors and as an independent
consultant to the issuer. The issuer's Series A Convertible Preferred Stock was
convertible into shares of Common Stock at any time and had no expiration date.

(2) Adarsh Sarma is a Managing Director and Member of Warburg Pincus LLC, a New
York limited liability company ("WP LLC"), and was appointed to the issuer's
Board of Directors in July 2005. Warburg Pincus & Co., a New York general
partnership ("WP"), is the managing member of Warburg Pincus Partners, LLC, a
New York limited liability company ("WP Partners"), the general partner of WP
VIII. WP VIII is managed by WP LLC. As a result, Mr. Sarma may be deemed to have
an indirect pecuniary interest (within the meaning of Rule 16a-1 of the
Securities Exchange Act of 1934, as amended (the "Exchange Act")) in an
indeterminate portion of the securities that may be deemed to be beneficially
owned by WP VIII, WP Partners, WP and WP LLC (collectively, the "Warburg Pincus
Entities").

As of the date hereof, WP VIII may be deemed to beneficially own, in the
aggregate, 43,684,517 shares of Common Stock issuable upon conversion of its
19,283,526.62 shares of Series A Preferred Stock. Mr. Sarma disclaims beneficial
ownership of all securities that may be deemed to be beneficially owned by the
Warburg Pincus Entities, except to the extent of any indirect pecuniary interest
therein. This Form 4 shall not be deemed an admission that Mr. Sarma or any
other person referred to herein is a beneficial owner of any securities for
purposes of Section 16 of the Exchange Act or for any other purpose.