Stock-Based Compensation Expense and Shareholders' Equity (Details 3) - Restricted stock units RSUs - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Number of RSUs Outstanding (in shares)
Balance at beginning of period (in shares)	2,384,673	2,932,155	2,634,085
Granted (in shares)	1,587,664	1,238,700	1,814,084
Released (in shares)	(1,217,337)	(1,398,676)	(1,260,758)
Canceled (in shares)	(309,302)	(387,506)	(255,256)
Balance at end of period (in shares)	2,445,698	2,384,673	2,932,155
Expected to vest as of July 31, 2020 (in shares)	2,445,698
Weighted Average Grant Date Fair Value (in dollars per share)
Balance at beginning of period (in USD per share)	$ 85.20	$ 69.43	$ 56.62
Granted (in USD per share)	106.65	100.01	79.65
Released (in USD per share)	82.73	69.20	56.92
Canceled (in USD per share)	87.25	75.16	63.66
Balance at end of period (in USD per share)	99.34	$ 85.20	$ 69.43
Expected to vest as of July 31, 2020 (in USD per share)	$ 99.34
Aggregate Intrinsic Value
Balance at beginning of period	$ 243,427	$ 252,752	$ 190,076
Released	121,915	133,050	103,957
Balance at end of period	287,761	$ 243,427	$ 252,752
Expected to vest as of July 31, 2020	$ 287,761