Discontinued operations - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2016	Apr. 30, 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	$ (182,000)	$ 84,000	$ (220,000)	$ 208,000
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	200		1,800
RF Neulink | Radio Mobile, Inc
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Royalty revenue		1,000		22,000
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	59,000	$ 84,000	$ 99,000	$ 194,000
Inventory Write-down	$ 173,000