Financial Assets and Liabilities - Short-term investments (Details) - USD ($) $ in Thousands		Apr. 30, 2016	Oct. 31, 2015
Cash equivalents
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		$ 316,904	$ 239,473
Gross unrealized gains		0	0
Gross unrealized losses less than 12 months		0	(1)
Gross unrealized losses 12 months or longer		0	0
Estimated fair value	[1]	316,904	239,472
Cash equivalents | Money market funds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		308,004	233,839
Gross unrealized gains		0	0
Gross unrealized losses less than 12 months		0	0
Gross unrealized losses 12 months or longer		0	0
Estimated fair value	[1]	308,004	233,839
Cash equivalents | Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		600	1,834
Gross unrealized gains		0	0
Gross unrealized losses less than 12 months		0	0
Gross unrealized losses 12 months or longer		0	0
Estimated fair value	[1]	600	1,834
Cash equivalents | U.S. government agency securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		3,399
Gross unrealized gains		0
Gross unrealized losses less than 12 months		0
Gross unrealized losses 12 months or longer		0
Estimated fair value	[1]	3,399
Cash equivalents | Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		4,901	3,500
Gross unrealized gains		0	0
Gross unrealized losses less than 12 months		0	0
Gross unrealized losses 12 months or longer		0	0
Estimated fair value	[1]	4,901	3,500
Cash equivalents | Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost			300
Gross unrealized gains			0
Gross unrealized losses less than 12 months			(1)
Gross unrealized losses 12 months or longer			0
Estimated fair value	[1]		299
Short-term investments
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		131,944	128,774
Gross unrealized gains		54	33
Gross unrealized losses less than 12 months		(22)	(60)
Gross unrealized losses 12 months or longer		0	0
Estimated fair value	[1]	131,976	128,747
Short-term investments | Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		12,010	12,129
Gross unrealized gains		0	0
Gross unrealized losses less than 12 months		0	0
Gross unrealized losses 12 months or longer		0	0
Estimated fair value	[1]	12,010	12,129
Short-term investments | U.S. government agency securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		11,612	12,615
Gross unrealized gains		2	3
Gross unrealized losses less than 12 months		(2)	(4)
Gross unrealized losses 12 months or longer		0	0
Estimated fair value	[1]	11,612	12,614
Short-term investments | Municipal bonds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		1,401	1,403
Gross unrealized gains		1	1
Gross unrealized losses less than 12 months		0	(1)
Gross unrealized losses 12 months or longer		0	0
Estimated fair value	[1]	1,402	1,403
Short-term investments | Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		13,598	9,800
Gross unrealized gains		0	0
Gross unrealized losses less than 12 months		0	0
Gross unrealized losses 12 months or longer		0	0
Estimated fair value	[1]	13,598	9,800
Short-term investments | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		66,777	67,201
Gross unrealized gains		43	27
Gross unrealized losses less than 12 months		(9)	(40)
Gross unrealized losses 12 months or longer		0	0
Estimated fair value	[1]	66,811	67,188
Short-term investments | Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		20,591	24,619
Gross unrealized gains		8	2
Gross unrealized losses less than 12 months		(10)	(13)
Gross unrealized losses 12 months or longer		0	0
Estimated fair value	[1]	20,589	24,608
Short-term investments | Non-U.S. government agency securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		1,005	1,007
Gross unrealized gains		0	0
Gross unrealized losses less than 12 months		(1)	(2)
Gross unrealized losses 12 months or longer		0	0
Estimated fair value	[1]	1,004	$ 1,005
Short-term investments | Other
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, cost		4,950
Gross unrealized gains		0
Gross unrealized losses less than 12 months		0
Gross unrealized losses 12 months or longer		0
Estimated fair value	[1]	$ 4,950

[1] See Note 6. Fair Value Measures for further discussion on fair values of cash equivalents and short-term investments.