Condensed Consolidated Statement 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, 2016		139,767,627
Beginning balance at Oct. 31, 2016	$ 766,341	$ 1,398	$ 6,715,478	$ (24,329)	$ (5,926,206)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	101,897				101,897
Other comprehensive income	18,834			18,834
Issuance of shares from employee equity plans (in shares)		2,905,157
Issuance of shares from employee equity plans	20,395	$ 29	20,366
Share-based compensation expense	36,843		36,843
Ending balance (in shares) at Jul. 31, 2017		142,672,784
Ending balance at Jul. 31, 2017	944,310	$ 1,427	6,772,687	(5,495)	(5,824,309)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Effect of adoption of new accounting standard	$ 62,123		832		61,291
Beginning balance (in shares) at Oct. 31, 2017	143,043,227	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)	(408,667)				(408,667)
Other comprehensive income	$ 2,312			2,312
Repurchase of common stock (in shares)	(3,028,118)	(3,028,118)
Repurchase of common stock	$ (74,787)	$ (30)	(74,757)
Issuance of shares from employee equity plans (in shares)		3,035,071
Issuance of shares from employee equity plans	22,735	$ 31	22,704
Share-based compensation expense	$ 38,896		38,896
Ending balance (in shares) at Jul. 31, 2018	143,050,180	143,050,180
Ending balance at Jul. 31, 2018	$ 1,778,954	$ 1,431	$ 6,797,857	$ (8,705)	$ (5,011,629)