Consolidated Statements of Changes in Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in-Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Oct. 31, 2016	$ 766,341	$ 1,398	$ 6,715,478	$ (24,329)	$ (5,926,206)
Beginning balance (in shares) at Oct. 31, 2016		139,767,627
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	1,261,953				1,261,953
Other comprehensive loss	13,312			13,312
Issuance of shares from employee equity plans	20,412	$ 32	20,380
Issuance of shares from employee equity plans (in shares)		3,275,600
Share-based compensation expense	48,360		48,360
Reversal of deferred tax asset valuation allowance	25,964		25,964
Ending balance at Oct. 31, 2017	2,136,342	$ 1,430	6,810,182	(11,017)	(4,664,253)
Ending balance (in shares) at Oct. 31, 2017		143,043,227
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(344,690)				(344,690)
Other comprehensive loss	5,237			5,237
Reclassification of cash conversion feature	(152,142)		(152,142)
Conversion of convertible notes into common shares	262,103	$ 122	261,981
Conversion of convertible notes into common shares (in shares)		12,236,146
Repurchases of common stock - repurchase program	(110,981)	$ (44)	(110,937)
Repurchases of common stock - repurchase program (in shares)		(4,290,801)
Issuance of shares from employee equity plans	23,127	$ 37	23,090
Issuance of shares from employee equity plans (in shares)		3,484,018
Share-based compensation expense	52,972		52,972
Shares repurchased for tax withholdings on vesting of restricted stock units	(4,757)	$ (2)	(4,755)
Shares repurchased for tax withholdings on vesting of restricted stock units (in shares)		(154,059)
Ending balance at Oct. 31, 2018	$ 1,929,334	$ 1,543	6,881,223	(5,780)	(4,947,652)
Ending balance (in shares) at Oct. 31, 2018	154,318,531	154,318,531
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 253,434				253,434
Other comprehensive loss	(16,304)			(16,304)
Conversion of convertible notes into common shares	52,944	$ 16	52,928
Conversion of convertible notes into common shares (in shares)		1,585,140
Repurchases of common stock - repurchase program	$ (150,076)	$ (38)	(150,038)
Repurchases of common stock - repurchase program (in shares)	(3,838,466,000)	(3,838,466)
Issuance of shares from employee equity plans	$ 22,947	$ 31	22,916
Issuance of shares from employee equity plans (in shares)	50,000	3,112,916
Share-based compensation expense	$ 59,736		59,736
Shares repurchased for tax withholdings on vesting of restricted stock units	(29,059)	$ (8)	(29,051)
Shares repurchased for tax withholdings on vesting of restricted stock units (in shares)		(774,271)
Ending balance at Oct. 31, 2019	$ 2,172,761	$ 1,544	$ 6,837,714	$ (22,084)	$ (4,644,413)
Ending balance (in shares) at Oct. 31, 2019	154,403,850	154,403,850