Stockholders' Equity - Share-Based Awards Available for Grant (Details) - shares		12 Months Ended
		Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares available for Grant, Beginning (in shares)		8,990,000	17,183,000	24,203,000
Additional shares authorized (in shares)		23,110,000
Options granted (in shares)		(1,786,000)	(2,553,000)	(1,981,000)
Restricted stock units granted (in shares)	[1]	(9,160,000)	(9,364,000)	(8,053,000)
Share-based awards canceled/forfeited/expired (in shares)	[1],[2]	4,010,000	3,724,000	3,014,000
Shares available for Grant, Ending (in shares)		25,164,000	8,990,000	17,183,000
Pool shares reduced for each share granted (in shares)		2.3
Pool shares increased for each share forfeited (in shares)		2.3

[1] RSUs granted from the pool of shares available for grant under our 2005 Equity Incentive Plan reduce the pool by 2.3 shares for each share granted. RSUs forfeited and returned to the pool of shares available for grant increase the pool by 2.3 shares for each share forfeited.

[2] Stock options and RSUs canceled, expired or forfeited under our 2005 Equity Incentive Plan are returned to the pool of shares available for grant. Shares withheld for income taxes upon vesting of RSUs that were granted on or after July 21, 2016 are also returned to the pool of shares available for grant. Stock options and RSUs canceled, expired or forfeited under older expired plans are not returned to the pool of shares available for grant.