Condensed Consolidated Statements of Changes in Stockholders’ Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in-Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance (in shares) at Oct. 31, 2017		143,043,227
Beginning balance at Oct. 31, 2017	$ 2,136,342	$ 1,430	$ 6,810,182	$ (11,017)	$ (4,664,253)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(459,507)				(459,507)
Other comprehensive income (loss)	5,945			5,945
Repurchase of common stock - repurchase program (in shares)		(1,627,233)
Repurchase of common stock - repurchase program	(39,147)	$ (16)	(39,131)
Issuance of shares from employee equity plans (in shares)		2,011,982
Issuance of shares from employee equity plans	11,804	$ 20	11,784
Share-based compensation expense	26,559		26,559
Ending balance (in shares) at Apr. 30, 2018		143,427,976
Ending balance at Apr. 30, 2018	$ 1,744,119	$ 1,434	6,810,226	(5,072)	(5,062,469)
Beginning balance (in shares) at Oct. 31, 2018	154,318,531	154,318,531
Beginning balance at Oct. 31, 2018	$ 1,929,334	$ 1,543	6,881,223	(5,780)	(4,947,652)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	86,354				86,354
Other comprehensive income (loss)	(13,426)			(13,426)
Repurchase of common stock - repurchase program (in shares)		(1,752,525)
Repurchase of common stock - repurchase program	(66,544)	$ (17)	(66,527)
Issuance of shares from employee equity plans (in shares)		1,875,159
Issuance of shares from employee equity plans	11,235	$ 19	11,216
Share-based compensation expense	29,362		29,362
Settlement of debt conversion liability (in shares)		1,585,140
Settlement of debt conversion liability	52,944	$ 16	52,928
Shares repurchased for tax withholdings on vesting of restricted stock units (in shares)		(459,604)
Shares repurchased for tax withholdings on vesting of stock unit awards	$ (15,865)	$ (5)	(15,860)
Ending balance (in shares) at Apr. 30, 2019	155,566,701	155,566,701
Ending balance at Apr. 30, 2019	$ 2,063,199	$ 1,556	$ 6,892,342	$ (19,206)	$ (4,811,493)