EX-99

                                                                    Exhibit 99.1

                            Explanation of Responses


(1) The stockholders are Warburg, Pincus Ventures, L.P., a Delaware limited
partnership ("WPV"), and Warburg Pincus & Co., a New York general partnership
("WP"). The sole general partner of WPV is Warburg Pincus Partners LLC, a New
York limited liability company ("WPP"), whose managing member is WP. Warburg
Pincus LLC, a New York limited liability company ("WP LLC" and together with
WPV, WPP and WP, the "Warburg Pincus Entities"), manages WPV. Charles R. Kaye
and Joseph P. Landy are Managing General Partners of WP and Managing Members of
WP LLC and may be deemed to control the Warburg Pincus Entities. Messrs. Kaye
and Landy disclaim beneficial ownership of all shares held by the Warburg Pincus
Entities. Kewsong Lee, a director of Knoll, Inc., is a general partner of WP and
a managing director and member of WP LLC. All shares indicated as owned by Mr.
Lee are included because of his affiliation with the Warburg Pincus Entities. By
reason of such affiliation, Mr. Lee 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 shares
reported herein. Mr. Lee disclaims "beneficial ownership" of such shares within
the meaning of Rule 13d-3 under the Exchange Act.

EX-24

                                                                      Exhibit 24

                                POWER OF ATTORNEY

     The undersigned hereby constitutes and appoints each of Scott A. Arenare,
Timothy J. Curt and Steven G. Schneider, acting together or individually,
his/her true and lawful attorneyin-fact to:

     (1)      execute for and on behalf of the undersigned Forms 3, 4 and 5,
              together with any amendments thereto, in accordance with the
              Securities Exchange Act of 1934, as amended, and the rules
              thereunder;

     (2)      do and perform any and all acts for and on behalf of the
              undersigned which may be necessary or desirable to complete
              the execution of any such Forms and the filing thereof with
              the United States Securities and Exchange Commission and any
              other person as may be required by law; and

     (3)      take any other action of any type whatsoever' in connection
              with the foregoing which, in the opinion of such
              attorney-in-fact, may be of benefit to, in the best interest
              of, or legally required by, the undersigned, it being
              understood that the documents executed by such
              attorney-in-fact on behalf of the undersigned pursuant to this
              power of attorney shall be in such form and shall contain such
              terms and conditions as such attorney-in-fact may approve in
              his discretion.

     The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform all and every act and thing whatsoever requisite,
necessary and proper to be done in the exercise of any of the rights and powers
herein granted, with full power of substitution or revocation, hereby ratifying
and confirming all that such attorney-in-fact, or his substitute or substitutes,
shall lawfully do or cause to be done by virtue of this power of attorney and
the rights and powers herein granted. The undersigned acknowledges that the
foregoing attorneys-in-fact, in serving in such capacity at the request of the
undersigned, are not assuming any of the undersigned's responsibilities to
comply with the Securities Exchange Act of 1934, as amended.

     This power of attorney shall continue in full force and effect until
revoked in writing by the undersigned or his/her attorney-in-fact.

     IN WITNESS WHEREOF, the undersigned has executed this Power of Attorney
this 15th day of May, 2004.

                                           Signature: /s/ Kewsong Lee
                                                      --------------------------

                                           Print Name:  Kewsong Lee