Short-term and Long-term Investments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Jan. 31, 2014	Oct. 31, 2013
Long Term Investments
U.S. government obligations	$ 110,031
U.S. government obligations [Member]
Long Term Investments
Amortized Cost	74,990	114,970
Gross Unrealized Gains	50	46
Gross Unrealized Losses	0	0
U.S. government obligations	75,040	115,016
Commercial paper [Member]
Long Term Investments
Amortized Cost	34,991	24,994
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
U.S. government obligations	34,991	24,994
Short-term investments [Member] | U.S. government obligations [Member]
Long Term Investments
Amortized Cost	59,993	99,974
Gross Unrealized Gains	9	11
Gross Unrealized Losses	0	0
U.S. government obligations	60,002	99,985
Short-term investments [Member] | Commercial paper [Member]
Long Term Investments
Amortized Cost	34,991	24,994
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
U.S. government obligations	34,991	24,994
Other Long-term investments [Member] | U.S. government obligations [Member]
Long Term Investments
Amortized Cost	14,997	14,996
Gross Unrealized Gains	41	35
Gross Unrealized Losses	0	0
U.S. government obligations	$ 15,038	$ 15,031