Earnings (Loss) Per Share Calculation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2015	Jul. 31, 2014
Numerator
Net income (loss)	$ 23,625	$ 16,160	$ 25,499	$ (9,934)
Add: Interest expense associated with 0.875% convertible senior notes due 2017	1,384	1,384	0	0
Net income (loss) used to calculate Diluted EPS	$ 25,009	$ 17,544	$ 25,499	$ (9,934)
Denominator
Basic weighted average shares outstanding	118,413	106,236	113,189	105,404
Add: Shares underlying outstanding stock options, employee stock purchase plan and restricted stock units	1,712	1,465	1,360	0
Add: Shares underlying 0.875% convertible senior notes due 2017	13,108	13,108	0	0
Dilutive weighted average shares outstanding	133,233	120,809	114,549	105,404
EPS
Basic EPS (in dollars per share)	$ 0.20	$ 0.15	$ 0.23	$ (0.09)
Diluted EPS (in dollars per share)	$ 0.19	$ 0.15	$ 0.22	$ (0.09)