Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Apr. 30, 2014
Assets:
U.S. government obligations	$ 105,091
Fair Value, Measurements, Recurring [Member] | Total [Member]
Assets:
Money market funds	226,925
U.S. government obligations	75,100
Commercial paper	49,989
Foreign currency forward contracts	296
Embedded redemption feature	190
Total assets measured at fair value	352,500
Liabilities:
Foreign currency forward contracts	3,548
Total liabilities measured at fair value	3,548
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets:
Money market funds	226,925
U.S. government obligations	0
Commercial paper	0
Foreign currency forward contracts	0
Embedded redemption feature	0
Total assets measured at fair value	226,925
Liabilities:
Foreign currency forward contracts	0
Total liabilities measured at fair value	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets:
Money market funds	0
U.S. government obligations	75,100
Commercial paper	49,989
Foreign currency forward contracts	296
Embedded redemption feature	0
Total assets measured at fair value	125,385
Liabilities:
Foreign currency forward contracts	3,548
Total liabilities measured at fair value	3,548
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Assets:
Money market funds	0
U.S. government obligations	0
Commercial paper	0
Foreign currency forward contracts	0
Embedded redemption feature	190
Total assets measured at fair value	190
Liabilities:
Foreign currency forward contracts	0
Total liabilities measured at fair value	0
Reconciliation of changes in Level 3 fair value measurements
Balance at October 31, 2013	2,740
Issuances	0
Settlements	0
Changes in unrealized gain (loss)	(2,550)
Transfers into Level 3	0
Transfers out of Level 3	0
Balance at April 30, 2014	$ 190