Sales by geographic area (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
Revenue, Major Customer [Line Items]
Sales revenue	$ 7,640	$ 8,315	$ 22,159	$ 22,223
United States
Revenue, Major Customer [Line Items]
Sales revenue	7,441	7,989	21,536	21,242
Canada
Revenue, Major Customer [Line Items]
Sales revenue	90	64	236	290
Israel
Revenue, Major Customer [Line Items]
Sales revenue	1	76	63	264
Mexico
Revenue, Major Customer [Line Items]
Sales revenue	85	135	234	324
All other
Revenue, Major Customer [Line Items]
Sales revenue	23	51	90	103
Foreign countries, total
Revenue, Major Customer [Line Items]
Sales revenue	$ 199	$ 326	$ 623	$ 981