Stock-Based Compensation Expense and Shareholders' Equity (Details 2) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	9 Months Ended
	Jan. 31, 2020	Apr. 30, 2020	Jul. 31, 2019
Number of Stock Options Outstanding
Balance at beginning of period (in shares)	216,727	216,727
Granted (in shares)		0
Exercised (in shares)		(88,328)
Canceled (in shares)		(3,822)
Balance at end of period (in shares)		124,577
Vested and expected to vest as of January 31, 2020 (in shares)		124,577
Exercisable as of January 31, 2020 (in shares)		109,915
Weighted Average Exercise Price
Balance at beginning of period (in dollars per share)	$ 34.10	$ 34.10
Exercised (in dollars per share)		34.85
Canceled (in dollars per share)		10.99
Balance at end of period (in dollars per share)		34.28
Vested and expected to vest as of January 31, 2020 (in dollars per share)		34.28
Exercisable as of January 31, 2020 (in dollars per share)		$ 37.38
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted Average Remaining Contractual Life	5 years 2 months 12 days	5 years 1 month 6 days
Vested and expected to vest as of April 30, 2020		5 years 1 month 6 days
Exercisable as of April 30, 2020		4 years 10 months 24 days
Share-based Compensation Arrangement by Share-based Payment Award, Aggregate Intrinsic Value [Abstract]
Aggregate intrinsic value		$ 7,046	$ 14,733
Exercised		5,970
Vested and expected to vest as of January 31, 2020		7,046
Exercisable as of January 31, 2020		$ 5,877
Share price (in dollars per share)		$ 90.84	$ 102.08
Restricted Stock Units (RSUs)
Number of Stock Awards Outstanding
Balance at beginning of period (in shares)	2,384,673	2,384,673
Granted (in shares)		1,367,381
Released (in shares)		(966,699)
Canceled (in shares)		(281,212)
Balance at end of period (in shares)		2,504,143
Expected to vest as of January 31, 2020 (in shares)		2,504,143
Weighted Average Grant Date Fair Value
Balance at beginning of period (in dollars per share)	$ 85.20	$ 85.20
Granted (in dollars per share)		106.68
Released (in dollars per share)		81.50
Canceled (in dollars per share)		86.19
Balance at end of period (in dollars per share)		97.52
Expected to vest as of January 31, 2020 (in dollars per share)		$ 97.52
Aggregate intrinsic value, Nonvested		$ 227,476	$ 243,427
Aggregate intrinsic value, Vested		95,938
Aggregate intrinsic value, Expected to vest		$ 227,476