X0303 4 2010-04-26 false 0001373671 Isilon Systems, Inc. ISLN 0001461927 Bennett George H 3101 WESTERN AVENUE SEATTLE WA 98121 false true false false SVP WW Field Operations Common Stock 2010-04-26 4 M false 5700 2.56 A 10700 D Common Stock 2010-04-26 4 S false 5700 13.7881 D 5000 D Stock Option (Right to Buy) 2.56 2010-04-26 4 M false 5700 0 D 2019-04-28 Common Stock 5700 369300 D The option is exercisable at the rate of 25% of the shares on April 6, 2010 and 1/12th of the remaining shares on each quarterly anniversary thereafter, such that the option will be fully exercisable on April 6, 2013. The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price, respectively, of shares disposed. These shares were sold in multiple transactions at prices ranging from $13.72 to $13.95, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth herein. Keenan M. Conder, Attorney in Fact 2010-04-28