Equity Incentive and Benefit Plans (Details) (USD $)	12 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009
Stock options outstanding
Shares available for Grant, Beginning balance	635,877	2,808,576	3,169,466
Number of Shares, Beginning balance	23,640,524	21,541,915	19,518,002
Weighted Average Exercise Price per Share, Beginning balance	$ 5.00	$ 3.32	$ 4.41
Weighted Average Remaining Contractual Term (Years), Beginning balance	5.9	6.7	7.4
Aggregate Intrinsic Value, Beginning balance	$ 283,285,534	$ 120,621,047	$ 44,913,703
Shares reserved for issuance, Shares available for Grant	4,680,314	4,337,195	4,141,807
Restricted stock awards granted, Shares available for Grant	(4,460,081)	(1,733,374)	(1,626,631)
Restricted stock awards forfeited, Shares available for Grant	355,781	280,683	565,582
Options granted, Shares available for Grant	(1,853,890)	(5,771,745)	(10,491,975)
Options granted, Number of Shares	1,853,890	5,771,745	10,491,975
Options granted, Weighted Average Exercise Price per Share	$ 21.88	$ 10.11	$ 3.82
Options granted, Weighted Average Fair Value per Share	$ 11.70	$ 5.60	$ 1.55
Options exercised, Number of Shares	(6,413,368)	(2,974,218)	(1,436,068)
Options exercised, Weighted Average Exercise Price per Share	$ 4.64	$ 2.73	$ 1.35
Options exercised, Aggregate Intrinsic Value	137,156,274	28,722,784	4,874,878
Options repurchased, Shares available for Grant		15,624	18,333
Options repurchased, Weighted Average Exercise Price per Share		$ 2.33	$ 0.49
Options cancelled, Shares available for Grant	916,102	698,918	7,031,994
Options cancelled, Number of Shares	(916,102)	(698,918)	(7,031,994)
Options cancelled, Weighted Average Exercise Price per Share	$ 10.11	$ 5.11	$ 7.48
Shares available for Grant, Ending balance	274,103	635,877	2,808,576
Number of Shares, Ending balance	18,164,944	23,640,524	21,541,915
Weighted Average Exercise Price per Share, Ending balance	$ 6.59	$ 5.00	$ 3.32
Weighted Average Remaining Contractual Term (Years), Ending balance	5.0	5.9	6.7
Aggregate Intrinsic Value, Ending balance	297,688,111	283,285,534	120,621,047
Options vested and expected to vest, Number of shares	17,763,527
Options vested and expected to vest, Weighted Average Exercise Price per Share	$ 6.41
Options vested and expected to vest, Weighted Average Remaining Contractual Term (Years)	5.0
Options vested and expected to vest, Aggregate Intrinsic Value	294,366,644
Options exercisable, Number of Shares	10,833,055
Options exercisable, Weighted Average Exercise Price per Share	$ 3.80
Options exercisable, Weighted Average Remaining Contractual Term (Years)	4.8
Options exercisable, Aggregate Intrinsic Value	$ 207,452,354