Sales by geographic area (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2016	Apr. 30, 2015
Revenue, Major Customer [Line Items]
Sales revenue	$ 7,735	$ 7,592	$ 14,519	$ 13,909
United States
Revenue, Major Customer [Line Items]
Sales revenue	7,603	7,235	14,095	13,254
Canada
Revenue, Major Customer [Line Items]
Sales revenue	75	112	146	226
Israel
Revenue, Major Customer [Line Items]
Sales revenue	0	135	62	188
Mexico
Revenue, Major Customer [Line Items]
Sales revenue	52	95	149	189
All other
Revenue, Major Customer [Line Items]
Sales revenue	5	15	67	52
Foreign countries, total
Revenue, Major Customer [Line Items]
Sales revenue	$ 132	$ 357	$ 424	$ 655