Financial Assets and Liabilities - Short-term investments (Details) - Cash equivalents - USD ($) $ in Thousands		Apr. 30, 2021	Oct. 31, 2020
Cash Equivalents [Line Items]
Cost		$ 234,243	$ 304,127
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]	234,243	304,127
Money market funds
Cash Equivalents [Line Items]
Cost		234,243	304,127
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]	$ 234,243	$ 304,127

[1] See Note 7. Fair Value Measures for further discussion on fair values of cash equivalents.