Stock-Based Compensation Expense and Shareholders' Equity (Details 2) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Oct. 31, 2020	Jul. 31, 2020
Number of Stock Options Outstanding
Balance at beginning of period (in shares)	80,332
Granted (in shares)	0
Exercised (in shares)	(39,169)
Canceled (in shares)	(654)
Balance at end of period (in shares)	40,509	80,332
Vested and expected to vest as of January 31, 2020 (in shares)	40,509
Exercisable as of January 31, 2020 (in shares)	34,585
Weighted Average Exercise Price
Balance at beginning of period (in dollars per share)	$ 29.80
Exercised (in dollars per share)	43.80
Canceled (in dollars per share)	11.23
Balance at end of period (in dollars per share)	16.56	$ 29.80
Vested and expected to vest as of January 31, 2020 (in dollars per share)	16.56
Exercisable as of January 31, 2020 (in dollars per share)	$ 17.48
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted Average Remaining Contractual Life	5 years 9 months 18 days	5 years 2 months 12 days
Vested and expected to vest as of October 31, 2020	5 years 9 months 18 days
Exercisable as of October 31, 2020	5 years 8 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Aggregate Intrinsic Value [Abstract]
Aggregate intrinsic value	$ 3,222	$ 7,058
Exercised	2,461
Vested and expected to vest as of January 31, 2020	3,222
Exercisable as of January 31, 2020	$ 2,719
Share price (in dollars per share)	$ 96.11	$ 117.66
Restricted Stock Units (RSUs)
Number of Stock Awards Outstanding
Balance at beginning of period (in shares)	2,445,698
Granted (in shares)	1,112,046
Released (in shares)	(339,759)
Canceled (in shares)	(88,564)
Balance at end of period (in shares)	3,129,421	2,445,698
Expected to vest as of January 31, 2020 (in shares)	3,129,421
Weighted Average Grant Date Fair Value
Balance at beginning of period (in dollars per share)	$ 99.34
Granted (in dollars per share)	111.55
Released (in dollars per share)	90.29
Canceled (in dollars per share)	100.38
Balance at end of period (in dollars per share)	104.63	$ 99.34
Expected to vest as of January 31, 2020 (in dollars per share)	$ 104.63
Aggregate intrinsic value, Nonvested	$ 300,769	$ 287,761
Aggregate intrinsic value, Vested	36,027
Aggregate intrinsic value, Expected to vest	$ 300,769