Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Retained earnings (accumulated deficit)
Beginning balance (in shares) at Jul. 31, 2020		83,461,925
Beginning balance at Jul. 31, 2020	$ 1,656,768	$ 8	$ 1,499,050	$ (5,246)	$ 162,956
Net loss	(20,190)				(20,190)
Issuance of common stock upon exercise of stock options (in shares)		39,169
Issuance of common stock upon exercise of stock options	1,716		1,716
Issuance of common stock upon vesting of Restricted Stock Units (RSU) (in shares)		339,759
Stock-based compensation	28,394		28,394
Repurchase and retirement of common stock (in shares)		(48,997)
Repurchase and retirement of common stock	(5,000)				(5,000)
Foreign currency translation adjustment	(694)			(694)
Unrealized gain (loss) on available-for-sale securities, net of tax	(1,480)			(1,480)
Reclassification adjustment for realized gain (loss) on available-for-sale securities, included in net income (loss)	347			347
Ending balance (in shares) at Oct. 31, 2020		83,791,856
Ending balance at Oct. 31, 2020	1,659,861	$ 8	1,529,160	(7,073)	137,766
Beginning balance (in shares) at Jul. 31, 2020		83,461,925
Beginning balance at Jul. 31, 2020	1,656,768	$ 8	1,499,050	(5,246)	162,956
Net loss	(65,475)
Reclassification adjustment for realized gain (loss) on available-for-sale securities, included in net income (loss)	1,003
Ending balance (in shares) at Apr. 30, 2021		83,280,955
Ending balance at Apr. 30, 2021	1,556,484	$ 8	1,588,143	(5,341)	(26,326)
Beginning balance (in shares) at Oct. 31, 2020		83,791,856
Beginning balance at Oct. 31, 2020	1,659,861	$ 8	1,529,160	(7,073)	137,766
Net loss	(8,652)				(8,652)
Issuance of common stock upon exercise of stock options (in shares)		9,415
Issuance of common stock upon exercise of stock options	104		104
Issuance of common stock upon vesting of Restricted Stock Units (RSU) (in shares)		283,454
Stock-based compensation	30,209		30,209
Repurchase and retirement of common stock (in shares)		(309,562)
Repurchase and retirement of common stock	(38,909)				(38,909)
Foreign currency translation adjustment	2,726			2,726
Unrealized gain (loss) on available-for-sale securities, net of tax	(996)			(996)
Reclassification adjustment for realized gain (loss) on available-for-sale securities, included in net income (loss)	320			320
Ending balance (in shares) at Jan. 31, 2021		83,775,163
Ending balance at Jan. 31, 2021	1,644,663	$ 8	1,559,473	(5,023)	90,205
Net loss	(36,633)				(36,633)
Issuance of common stock upon exercise of stock options (in shares)		3,647
Issuance of common stock upon exercise of stock options	102		102
Issuance of common stock upon vesting of Restricted Stock Units (RSU) (in shares)		266,927
Stock-based compensation	28,568		28,568
Repurchase and retirement of common stock (in shares)		(764,782)
Repurchase and retirement of common stock	(79,898)				(79,898)
Foreign currency translation adjustment	403			403
Unrealized gain (loss) on available-for-sale securities, net of tax	(1,057)			(1,057)
Reclassification adjustment for realized gain (loss) on available-for-sale securities, included in net income (loss)	336			336
Ending balance (in shares) at Apr. 30, 2021		83,280,955
Ending balance at Apr. 30, 2021	1,556,484	$ 8	1,588,143	(5,341)	(26,326)
Beginning balance (in shares) at Jul. 31, 2021		83,194,157
Beginning balance at Jul. 31, 2021	1,544,894	$ 8	1,617,204	(6,218)	(66,100)
Net loss	(51,276)				(51,276)
Issuance of common stock upon exercise of stock options (in shares)		1,518
Issuance of common stock upon exercise of stock options	17		17
Issuance of common stock upon vesting of Restricted Stock Units (RSU) (in shares)		335,653
Stock-based compensation	32,533		32,533
Repurchase and retirement of common stock (in shares)		(226,172)
Repurchase and retirement of common stock	(26,262)				(26,262)
Foreign currency translation adjustment	(724)			(724)
Unrealized gain (loss) on available-for-sale securities, net of tax	(868)			(868)
Reclassification adjustment for realized gain (loss) on available-for-sale securities, included in net income (loss)	69			69
Ending balance (in shares) at Oct. 31, 2021		83,305,156
Ending balance at Oct. 31, 2021	1,498,383	$ 8	1,649,754	(7,741)	(143,638)
Beginning balance (in shares) at Jul. 31, 2021		83,194,157
Beginning balance at Jul. 31, 2021	1,544,894	$ 8	1,617,204	(6,218)	(66,100)
Net loss	(149,401)
Reclassification adjustment for realized gain (loss) on available-for-sale securities, included in net income (loss)	173
Ending balance (in shares) at Apr. 30, 2022		83,816,227
Ending balance at Apr. 30, 2022	1,449,650	$ 8	1,721,241	(18,647)	(252,952)
Beginning balance (in shares) at Oct. 31, 2021		83,305,156
Beginning balance at Oct. 31, 2021	1,498,383	$ 8	1,649,754	(7,741)	(143,638)
Net loss	(40,681)				(40,681)
Issuance of common stock upon exercise of stock options (in shares)		7,230
Issuance of common stock upon exercise of stock options	80		80
Issuance of common stock upon vesting of Restricted Stock Units (RSU) (in shares)		329,987
Stock-based compensation	38,148		38,148
Repurchase and retirement of common stock (in shares)		(96,373)
Repurchase and retirement of common stock	(11,189)				(11,189)
Foreign currency translation adjustment	(2,363)			(2,363)
Unrealized gain (loss) on available-for-sale securities, net of tax	(1,933)			(1,933)
Reclassification adjustment for realized gain (loss) on available-for-sale securities, included in net income (loss)	23			23
Ending balance (in shares) at Jan. 31, 2022		83,546,000
Ending balance at Jan. 31, 2022	1,480,468	$ 8	1,687,982	(12,014)	(195,508)
Net loss	(57,444)				(57,444)
Issuance of common stock upon exercise of stock options (in shares)		1,684
Issuance of common stock upon exercise of stock options	18		18
Issuance of common stock upon vesting of Restricted Stock Units (RSU) (in shares)		268,543
Stock-based compensation	33,241		33,241
Foreign currency translation adjustment	(2,769)			(2,769)
Unrealized gain (loss) on available-for-sale securities, net of tax	(3,945)			(3,945)
Reclassification adjustment for realized gain (loss) on available-for-sale securities, included in net income (loss)	81			81
Ending balance (in shares) at Apr. 30, 2022		83,816,227
Ending balance at Apr. 30, 2022	$ 1,449,650	$ 8	$ 1,721,241	$ (18,647)	$ (252,952)