Sales by geographic area (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Oct. 31, 2015
Revenue, Major Customer [Line Items]
Sales revenue	$ 6,617	$ 6,784	$ 6,784
United States
Revenue, Major Customer [Line Items]
Sales revenue	6,536	6,492
Canada
Revenue, Major Customer [Line Items]
Sales revenue	46	71
Israel
Revenue, Major Customer [Line Items]
Sales revenue	0	62
Mexico
Revenue, Major Customer [Line Items]
Sales revenue	7	97
All other
Revenue, Major Customer [Line Items]
Sales revenue	28	62
Foreign countries, total
Revenue, Major Customer [Line Items]
Sales revenue	$ 81	$ 292