Segment Information and Significant Customers (Details) (USD $) In Thousands	12 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009
Schedule of total revenue by geographic region
Total revenue	$ 396,514	$ 266,534	$ 199,259
United States [Member]
Schedule of total revenue by geographic region
Total revenue	250,995	166,584	129,991
Europe, Middle East and Africa [Member]
Schedule of total revenue by geographic region
Total revenue	62,595	38,140	34,178
Asia Pacific [Member]
Schedule of total revenue by geographic region
Total revenue	70,171	51,110	27,023
Rest of World [Member]
Schedule of total revenue by geographic region
Total revenue	$ 12,753	$ 10,700	$ 8,067