Basis Of Presentation (Details) (USD $) In Millions	3 Months Ended	6 Months Ended	9 Months Ended		12 Months Ended
	Jul. 31, 2010	Apr. 30, 2011	Jul. 30, 2011	Jul. 31, 2010	Oct. 30, 2010
Basis Of Presentation
Reclassification of SE costs from cost of revenues to sales and marketing expenses	$ 33.7			$ 97.6
Cumulative amount of error for sales discount			14.0
Change in net revenue	(0.7)	1.8		1.5
Changes in net current assets and stockholders' equity					8.6
Change in net income	$ (0.6)	$ 1.8		$ 1.1