Intangible assets (Detail) - USD ($) $ in Thousands	Apr. 30, 2019	Oct. 31, 2018
Intangible Assets [Line Items]
Amortizable intangible assets, net	$ 1,229	$ 1,367
Non-amortizable intangible assets, Trademarks	657	657
Customer relationships (estimated lives 7 - 15 years)
Intangible Assets [Line Items]
Amortizable intangible assets, gross	2,879	2,879
Amortizable intangible assets, Accumulated amortization	(1,752)	(1,619)
Amortizable intangible assets, net	1,127	1,260
Patents (estimated life 14 years)
Intangible Assets [Line Items]
Amortizable intangible assets, gross	142	142
Amortizable intangible assets, Accumulated amortization	(40)	(35)
Amortizable intangible assets, net	$ 102	$ 107