- Condensed Consolidated Balance Sheet (Details) - Fair value, Measurements, Recurring - USD ($) $ in Thousands	Jan. 31, 2018	Oct. 31, 2017
Assets:
Total assets measured at fair value	$ 897,380	$ 900,641
Liabilities:
Total liabilities measured at fair value	2,415	2,129
Cash equivalents
Assets:
Cash equivalents	551,639	571,280
Short-term investments
Assets:
Short-term investments	278,743	279,133
Prepaid expenses and other
Assets:
Prepaid expenses and other	3,730	227
Long-term investments
Assets:
Long-term investments	59,151	49,783
Other long-term assets
Assets:
Other long-term assets	4,117	218
Accrued liabilities
Liabilities:
Accrued liabilities	2,415	2,129
Level 1
Assets:
Total assets measured at fair value	521,698	511,355
Liabilities:
Total liabilities measured at fair value	0	0
Level 1 | Cash equivalents
Assets:
Cash equivalents	521,698	511,355
Level 1 | Short-term investments
Assets:
Short-term investments	0	0
Level 1 | Prepaid expenses and other
Assets:
Prepaid expenses and other	0	0
Level 1 | Long-term investments
Assets:
Long-term investments	0	0
Level 1 | Other long-term assets
Assets:
Other long-term assets	0	0
Level 1 | Accrued liabilities
Liabilities:
Accrued liabilities	0	0
Level 2
Assets:
Total assets measured at fair value	375,682	389,286
Liabilities:
Total liabilities measured at fair value	2,415	2,129
Level 2 | Cash equivalents
Assets:
Cash equivalents	29,941	59,925
Level 2 | Short-term investments
Assets:
Short-term investments	278,743	279,133
Level 2 | Prepaid expenses and other
Assets:
Prepaid expenses and other	3,730	227
Level 2 | Long-term investments
Assets:
Long-term investments	59,151	49,783
Level 2 | Other long-term assets
Assets:
Other long-term assets	4,117	218
Level 2 | Accrued liabilities
Liabilities:
Accrued liabilities	2,415	2,129
Level 3
Assets:
Total assets measured at fair value	0	0
Liabilities:
Total liabilities measured at fair value	0	0
Level 3 | Cash equivalents
Assets:
Cash equivalents	0	0
Level 3 | Short-term investments
Assets:
Short-term investments	0	0
Level 3 | Prepaid expenses and other
Assets:
Prepaid expenses and other	0	0
Level 3 | Long-term investments
Assets:
Long-term investments	0	0
Level 3 | Other long-term assets
Assets:
Other long-term assets	0	0
Level 3 | Accrued liabilities
Liabilities:
Accrued liabilities	$ 0	$ 0