Discontinued operations - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	$ 147,000	$ 152,000	$ (74,000)	$ 359,000
Inventory Write-down			0	10,000
RF Neulink
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Royalty revenue	19,000		20,000
RF Neulink | Radio Mobile, Inc
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Royalty revenue		48,000		70,000
Bioconnect division [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	129,000	$ 123,000	$ 94,000	$ 317,000
Inventory Write-down	$ 158,000