Share-Based Compensation Expense (Details Textual) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended		1 Months Ended		1 Months Ended	3 Months Ended		9 Months Ended	3 Months Ended
	Jul. 31, 2012 plan	Jul. 31, 2012 Stock Options [Member] Y	Jul. 31, 2012 Stock Options [Member]	Jul. 31, 2011 Stock Options [Member]	Jul. 31, 2012 Restricted Stock Units (RSUs) [Member] Y	Jul. 31, 2012 Restricted Stock Units (RSUs) [Member]	Jul. 31, 2011 Restricted Stock Units (RSUs) [Member]	Mar. 31, 2012 2008 Plan [Member]	Jul. 31, 2012 2008 Plan [Member]	Mar. 31, 2012 2003 Employee Stock Purchase Plan [Member]	Jul. 31, 2012 2003 Employee Stock Purchase Plan [Member]	Jul. 31, 2012 2003 Employee Stock Purchase Plan [Member] Employee Stock [Member]	Jul. 31, 2012 2003 Employee Stock Purchase Plan [Member] Employee Stock [Member]	Jul. 31, 2012 Minimum [Member] Restricted Stock Units (RSUs) [Member]	Jul. 31, 2012 Maximum [Member] Restricted Stock Units (RSUs) [Member]	Jul. 31, 2012 Maximum [Member] 2003 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of active equity compensation plans (in plans)	2
Number of additional shares authorized (in shares)								5.5		5.0
Remaining authorized shares available for issuance (in shares)								18.5	7.0			7.6	7.6
Intrinsic value of option exercised			$ 0.3	$ 3.3
Vesting period of service-based awards		4 years			three or four-year									3 years	4 years
Total fair value of restricted stock units vested and converted into common stock						21.4	38.3
Weighted average fair value of each restricted stock unit granted (per share)						$ 11.00	$ 20.16
Plan term (in years)											10 years
Shares authorized for issuance under plan (in shares)																8.2
Maximum number of shares increase under ESPP (in shares)												0.6
Offer period (in months)												6 months
ESPP discount percentage purchase date												85.00%
Shares issued under ESPP (in shares)													1.2
Unrecognized share-based compensation	$ 56.3	$ 0.3	$ 0.3		$ 56.0	$ 56.0
Weighted-average period for recognition of share-based compensation (in years)		0.5			1.4