Contingencies (Details) - USD ($)	3 Months Ended	12 Months Ended
	Jan. 31, 2019	Oct. 31, 2018
Loss Contingencies [Line Items]
Patent cross-license	7 years
Mentor Patent Litigation
Loss Contingencies [Line Items]
Payments for legal settlements		$ 65,000,000
Minimum | Mentor Patent Litigation
Loss Contingencies [Line Items]
Potential one-time termination charge	$ 0.0
Maximum | Mentor Patent Litigation
Loss Contingencies [Line Items]
Potential one-time termination charge	$ 25,000,000