CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' DEFICIT - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Stockholders' equity, beginning balance at Jul. 31, 2020	$ (274,977)	$ 5	$ 2,245,180	$ 2,030	$ (2,522,192)
Stockholders' equity, beginning balance (in shares) at Jul. 31, 2020		201,949,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock through employee equity incentive plans	1,631		1,631
Issuance of common stock through employee equity incentive plans, net of repurchases (in shares)		3,117,000
Issuance of common stock from ESPP purchase	18,070		18,070
Issuance of common stock from ESPP purchase (in shares)		1,456,000
Repurchase and retirement of common stock	(125,079)		(54,176)		(70,903)
Repurchase and retirement of common stock (in shares)		(5,176,000)
Stock-based compensation	89,198		89,198
Other comprehensive loss	(1,150)			(1,150)
Net loss	(265,048)				(265,048)
Stockholders' equity, ending balance at Oct. 31, 2020	(557,355)	$ 5	2,299,903	880	(2,858,143)
Stockholders' equity, ending balance (in shares) at Oct. 31, 2020		201,346,000
Stockholders' equity, beginning balance at Jul. 31, 2020	(274,977)	$ 5	2,245,180	2,030	(2,522,192)
Stockholders' equity, beginning balance (in shares) at Jul. 31, 2020		201,949,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(676,078)
Stockholders' equity, ending balance at Apr. 30, 2021	(746,774)	$ 5	2,522,302	92	(3,269,173)
Stockholders' equity, ending balance (in shares) at Apr. 30, 2021		211,531,000
Stockholders' equity, beginning balance at Oct. 31, 2020	(557,355)	$ 5	2,299,903	880	(2,858,143)
Stockholders' equity, beginning balance (in shares) at Oct. 31, 2020		201,346,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock through employee equity incentive plans	2,222		2,222
Issuance of common stock through employee equity incentive plans, net of repurchases (in shares)		2,892,000
Stock-based compensation	84,454		84,454
Other comprehensive loss	(323)			(323)
Net loss	(287,390)				(287,390)
Stockholders' equity, ending balance at Jan. 31, 2021	(758,392)	$ 5	2,386,579	557	(3,145,533)
Stockholders' equity, ending balance (in shares) at Jan. 31, 2021		204,238,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock through employee equity incentive plans	8,340		8,340
Issuance of common stock through employee equity incentive plans, net of repurchases (in shares)		4,769,000
Issuance of common stock from ESPP purchase	32,097		32,097
Issuance of common stock from ESPP purchase (in shares)		2,524,000
Stock-based compensation	95,286		95,286
Other comprehensive loss	(465)			(465)
Net loss	(123,640)				(123,640)
Stockholders' equity, ending balance at Apr. 30, 2021	(746,774)	$ 5	2,522,302	92	(3,269,173)
Stockholders' equity, ending balance (in shares) at Apr. 30, 2021		211,531,000
Stockholders' equity, beginning balance at Jul. 31, 2021	(1,012,041)	$ 5	2,615,317	(8)	(3,627,355)
Stockholders' equity, beginning balance (ASU 2020-06) at Jul. 31, 2021	$ (48,013)		(148,598)		100,585
Stockholders' equity, beginning balance (in shares) at Jul. 31, 2021	214,210,000	214,210,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
2026 Notes derivative liability reclassification	$ 698,213		698,213
Issuance of common stock through employee equity incentive plans	1,352		1,352
Issuance of common stock through employee equity incentive plans, net of repurchases (in shares)		2,809,000
Issuance of common stock from ESPP purchase	28,786		28,786
Issuance of common stock from ESPP purchase (in shares)		1,309,000
Repurchase and retirement of common stock	(58,570)		(14,852)		(43,718)
Repurchase and retirement of common stock (in shares)		(1,369,000)
Unwinding of 2023 Notes hedges	39,880		39,880
Unwinding of 2023 Notes warrants	(18,390)		(18,390)
Stock-based compensation	90,547		90,547
Other comprehensive loss	(651)			(651)
Net loss	(419,852)				(419,852)
Stockholders' equity, ending balance at Oct. 31, 2021	(698,739)	$ 5	3,292,255	(659)	(3,990,340)
Stockholders' equity, ending balance (in shares) at Oct. 31, 2021		216,959,000
Stockholders' equity, beginning balance at Jul. 31, 2021	(1,012,041)	$ 5	2,615,317	(8)	(3,627,355)
Stockholders' equity, beginning balance (ASU 2020-06) at Jul. 31, 2021	$ (48,013)		(148,598)		100,585
Stockholders' equity, beginning balance (in shares) at Jul. 31, 2021	214,210,000	214,210,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (646,548)
Stockholders' equity, ending balance at Apr. 30, 2022	$ (721,866)	$ 5	3,501,311	(6,146)	(4,217,036)
Stockholders' equity, ending balance (in shares) at Apr. 30, 2022	224,285,000	224,285,000
Stockholders' equity, beginning balance at Oct. 31, 2021	$ (698,739)	$ 5	3,292,255	(659)	(3,990,340)
Stockholders' equity, beginning balance (in shares) at Oct. 31, 2021		216,959,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock through employee equity incentive plans	1,914		1,914
Issuance of common stock through employee equity incentive plans, net of repurchases (in shares)		3,580,000
Stock-based compensation	88,045		88,045
Other comprehensive loss	(1,776)			(1,776)
Net loss	(115,061)				(115,061)
Stockholders' equity, ending balance at Jan. 31, 2022	(725,617)	$ 5	3,382,214	(2,435)	(4,105,401)
Stockholders' equity, ending balance (in shares) at Jan. 31, 2022		220,539,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock through employee equity incentive plans	744		744
Issuance of common stock through employee equity incentive plans, net of repurchases (in shares)		2,228,000
Issuance of common stock from ESPP purchase	33,847		33,847
Issuance of common stock from ESPP purchase (in shares)		1,518,000
Stock-based compensation	84,506		84,506
Other comprehensive loss	(3,711)			(3,711)
Net loss	(111,635)				(111,635)
Stockholders' equity, ending balance at Apr. 30, 2022	$ (721,866)	$ 5	$ 3,501,311	$ (6,146)	$ (4,217,036)
Stockholders' equity, ending balance (in shares) at Apr. 30, 2022	224,285,000	224,285,000