Net Income (Loss) Per Common Share (Details) (USD $) In Thousands, except Per Share data	12 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009
Net income (loss) per common share
Net income (loss)	$ 70,688	$ (33,998)	$ (23,413)
Weighted-average common shares outstanding - basic	100,299	89,978	84,612
Dilutive effect of employee stock plans	16,818
Weighted-average common shares outstanding - diluted	117,117	89,978	84,612
Net income (loss) per common share - basic	$ 0.70	$ (0.38)	$ (0.28)
Net income (loss) per common share - diluted	$ 0.60	$ (0.38)	$ (0.28)