EX-99.1 4 dex991.txt AGREEMENT CUSIP No. 452327109 13G Page 26 of 27 Pages Exhibit 99.1 AGREEMENT Pursuant to Rule 13d-1(k)(1) promulgated pursuant to the Securities Exchange Act of 1934, as amended, the undersigned agree that the attached Schedule 13G is being filed on behalf of each of the undersigned. February 14, 2002 VENROCK ASSOCIATES By: /s/ Anthony B. Evnin --------------------------- Anthony B. Evnin General Partner February 14, 2002 VENROCK ASSOCIATES II, L.P. By: /s/ Anthony B. Evnin --------------------------- Anthony B. Evnin General Partner February 14, 2002 VENROCK ENTREPRENEURS FUND, L.P. By: Venrock Management LLC, its General Partner By: /s/ Anthony B. Evnin --------------------------- Anthony B. Evnin Member February 14, 2002 VENROCK MANAGEMENT LLC By: /s/ Anthony B. Evnin --------------------------- Anthony B. Evnin Member February 14, 2002 GENERAL PARTNERS / MEMBERS * ------------------------------------ Michael C. Brooks * ------------------------------------ Joseph E. Casey * ------------------------------------ Eric S. Copeland * ------------------------------------ Anthony B. Evnin * ------------------------------------ Thomas R. Frederick /s/ Terence J. Garnett ------------------------------------ Terence J. Garnett CUSIP No. 452327109 13G Page 27 of 27 Pages * ------------------------------------ David R. Hathaway * ------------------------------------ Patrick F. Latterell /s/ Bryan E. Roberts ------------------------------------ Bryan E. Roberts * ------------------------------------ Ray A. Rothrock * ------------------------------------ Kimberley A. Rummelsburg * ------------------------------------ Anthony Sun * ------------------------------------ Michael F. Tyrrell * By: /s/ Anthony B. Evnin ----------------------------- Anthony B. Evnin Attorney-in-Fact