Segment Disclosure - Additional information (Detail)	3 Months Ended	6 Months Ended
Apr. 30, 2018 Segment Customer	Apr. 30, 2017 Segment Customer	Apr. 30, 2018 Segment Customer	Apr. 30, 2017 Segment Customer
Segment Reporting Information [Line Items]
Number of reportable operating segment \| Segment	1	1	1	1
Customer concentration risk \| Sales revenue
Segment Reporting Information [Line Items]
Number of major customers \| Customer	1	1	1	1

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

No definition available.

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration