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, 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)	(473,363)				(473,363)
Other comprehensive loss	13,392			13,392
Repurchase of common stock - repurchase program (in shares)		(262,487)
Repurchase of common stock - repurchase program	(5,755)	$ (3)	(5,752)
Issuance of shares from employee equity plans (in shares)		1,400,042
Issuance of shares from employee equity plans	11,008	$ 15	10,993
Share-based compensation expense	12,393		12,393
Ending balance (in shares) at Jan. 31, 2018		144,180,782
Ending balance at Jan. 31, 2018	$ 1,756,140	$ 1,442	6,828,648	2,375	(5,076,325)
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)	33,616				33,616
Other comprehensive loss	(4,860)			(4,860)
Repurchase of common stock - repurchase program (in shares)		(591,897)
Repurchase of common stock - repurchase program	(21,162)	$ (6)	(21,156)
Issuance of shares from employee equity plans (in shares)		1,329,352
Issuance of shares from employee equity plans	10,899	$ 13	10,886
Share-based compensation expense	13,755		13,755
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)		(304,916)
Shares repurchased for tax withholdings on vesting of restricted stock units	$ (10,026)	$ (3)	(10,023)
Ending balance (in shares) at Jan. 31, 2019	156,336,210	156,336,210
Ending balance at Jan. 31, 2019	$ 2,054,305	$ 1,563	$ 6,927,613	$ (10,640)	$ (4,864,231)