Exhibit A AMENDED AND RESTATED AGREEMENT OF FILING OF SCHEDULE 13G The undersigned acknowledge and agree that the foregoing statement on Schedule 13G is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on...

                                                                       Exhibit A

            AMENDED AND RESTATED AGREEMENT OF FILING OF SCHEDULE 13G

The undersigned acknowledge and agree that the foregoing statement on Schedule
13G is filed on behalf of each of the undersigned and that all subsequent
amendments to this statement on Schedule 13G shall be filed on behalf of each of
the undersigned without the necessity of additional joint filing statements. The
undersigned acknowledge that each shall be responsible for the timely filing of
such amendments, and for the completeness and accuracy of the information
concerning the others, except to the extent that it knows or has reason to
believe that such information is inaccurate. This Agreement may be executed in
any number of counterparts and all such counterparts taken together shall
constitute one and the same instrument.

Dated:  November 22, 2005


                                  WARBURG, XXXXXX EQUITY PARTNERS, L.P.

                                  By:  Warburg Pincus Partners LLC, as General
                                       Partner

                                       By:  Warburg Pincus & Co., its Managing
                                            Member

                                            By:  /s/ Xxxxx X. Xxxxxxx
                                                 ---------------------
                                                 Name:  Xxxxx X. Xxxxxxx
                                                 Title: Partner


                                  WARBURG, XXXXXX VENTURES INTERNATIONAL, L.P.

                                  By:  Warburg Pincus Partners LLC, as General
                                       Partner

                                       By:  Warburg Pincus & Co., its Managing
                                            Member

                                            By:  /s/ Xxxxx X. Xxxxxxx
                                                 ---------------------
                                                 Name:  Xxxxx X. Xxxxxxx
                                                 Title: Partner


                                  WARBURG, XXXXXX VENTURES, L.P.

                                  By:  Warburg Pincus Partners LLC, as General
                                       Partner

                                       By:  Warburg Pincus & Co., its Managing
                                            Member

                                            By:  /s/ Xxxxx X. Xxxxxxx
                                                 ---------------------
                                                 Name:  Xxxxx X. Xxxxxxx
                                                 Title: Partner





                                  WARBURG PINCUS & CO.

                                  By:  /s/ Xxxxx X. Xxxxxxx
                                       -----------------------------------------
                                       Name:  Xxxxx X. Xxxxxxx
                                       Title: Partner


                                  WARBURG PINCUS LLC

                                  By:  /s/ Xxxxx X. Xxxxxxx
                                       -----------------------------------------
                                       Name:  Xxxxx X. Xxxxxxx
                                       Title: Partner


                                  WARBURG, XXXXXX VENTURES, L.P.

                                  By:  Warburg Pincus & Co., its Managing
                                       Member

                                       By:  /s/ Xxxxx X. Xxxxxxx
                                            ---------------------
                                            Name:  Xxxxx X. Xxxxxxx
                                            Title: Partner