Commitments and Contingencies - Narrative (Details) - USD ($)	3 Months Ended
	Apr. 30, 2018	Apr. 30, 2017		Jan. 31, 2018	Oct. 31, 2017
Other Commitments [Line Items]
Deferred rent	$ 9,000,000			$ 5,500,000
Rent expense	3,400,000	$ 2,200,000
Letters of credit issued and outstanding	12,400,000			$ 12,200,000
Restricted cash	8,565,000	$ 263,000	[1]
Letter of Credit
Other Commitments [Line Items]
Draws on line of credit					$ 0
San Francisco - Ten Year Lease
Other Commitments [Line Items]
Restricted cash	$ 8,000,000

[1] See Note 2 for a summary of adjustments.