Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified						3 Months Ended
	Jan. 31, 2014	Oct. 31, 2013	Jan. 31, 2014 Fair Value, Measurements, Recurring [Member] Total [Member]	Jan. 31, 2014 Fair Value, Measurements, Recurring [Member] Level 1 [Member]	Jan. 31, 2014 Fair Value, Measurements, Recurring [Member] Level 2 [Member]	Jan. 31, 2014 Fair Value, Measurements, Recurring [Member] Level 3 [Member]
Assets:
Money market funds			$ 243,454	$ 243,454	$ 0	$ 0
U.S. government obligations	110,031		75,040	0	75,040	0
Commercial paper			49,990	0	49,990	0
Foreign currency forward contracts			449	0	449	0
Embedded redemption feature	1,650	2,740	1,650	0	0	1,650
Total assets measured at fair value			370,583	243,454	125,479	1,650
Liabilities:
Foreign currency forward contracts			2,234	0	2,234	0
Total liabilities measured at fair value			2,234	0	2,234	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)						(1,090)
Transfers into Level 3						0
Transfers out of Level 3						0
Balance at January 31, 2014						$ 1,650