Stockholders' Equity (Narrative) (Details) (USD $)	12 Months Ended						12 Months Ended
	Aug. 31, 2011	Aug. 31, 2011 Plan 2011 [Member] Employee Stock Option [Member]	Feb. 28, 2011 Plan 2011 [Member] Employee Stock Purchase Plan [Member]	Feb. 28, 2009 Plan 2002 [Member] Employee Stock Purchase Plan [Member]	Feb. 28, 2006 Plan 2002 [Member] Employee Stock Purchase Plan [Member]	Feb. 28, 2002 Plan 2002 [Member] Employee Stock Purchase Plan [Member]	Aug. 31, 2011 Restricted Stock [Member]	Aug. 31, 2011 Employee Stock Option [Member]	Aug. 31, 2010 Employee Stock Option [Member]	Aug. 31, 2009 Employee Stock Option [Member]	Aug. 31, 2011 Employee Stock Purchase Plan [Member]	Aug. 31, 2010 Employee Stock Purchase Plan [Member]	Aug. 31, 2009 Employee Stock Purchase Plan [Member]
Range of vesting possibilities for performance condition	0% to 200%
Options granted	0
Maximum aggregate number of shares subject to awards	8,850,000	8,850,000	6,000,000
Performance goal full achievement	100.00%
Unrecognized compensation related to non-vested Options costs							$ 63,400,000	$ 800,000
Award vesting period, years	three						three
Term of stock option plan and eligibility period for participating in ESPP, days	90
Weighted average period for recognized stock-based compensation expense, in years							1.4	1.1
Weighted-average grant-date fair value per share									$ 6.36	$ 3.52
Intrinsic value of Options exercised								7,500,000	300,000	3,600
Fair value of Options vested								$ 7,500,000	$ 17,600,000	$ 24,900,000
Shares reserved under ESPP						2,000,000
Additional shares authorized under ESPP				3,000,000	2,000,000
Maximum percentage of an employee's salary that can be used to purchase shares under the ESPP											10.00%
Percentage of fair market value fixed for pricing											85.00%
Shares issued under ESPP	6,616,632										824,913	1,127,017	1,248,314