Stock-based compensation and equity transactions - Additional Information (Detail) - USD ($)		3 Months Ended			9 Months Ended
	Apr. 07, 2016	Jul. 31, 2016	Jan. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining life of options outstanding					5 years 11 days
Weighted average remaining contractual life of options exercisable					3 years 4 months 24 days
Weighted average life of options vested and expected to vest					5 years 7 days
Aggregate intrinsic value of options outstanding		$ 200,000			$ 200,000
Aggregate intrinsic value of options exercisable		200,000			200,000
Aggregate intrinsic value of options vested and expected to vest		200,000			200,000
Non-vested stock-based arrangements yet to be recognized		563,000			$ 563,000
Stock based arrangements yet to be recognized, weighted average period expected to be recognized					5 years 3 months 18 days
Non-employee director annual grant		$ 30,000			$ 30,000
Options granted for each non-employee director			51,192
Value of stock option issued					$ 15,000
Fair value of stock option		$ 0.87			$ 0.87
Stock based compensation expense		$ 54,000		$ 83,000	$ 156,000	$ 184,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value					$ 3.36	$ 1.08
Comnet Telecom Supply Inc [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Business Acquisition Cost Of Acquired Entity Purchase Price value		$ 1,060,000		$ 1,060,000	$ 1,060,000	$ 1,060,000
Business Acquisition Unregistered Common Stock Shares					252,381	252,381
Chief Operating Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, options, grants in period, gross	33,744
Stock Issued During Period, Value, Share-based Compensation, Gross					$ 8,750
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price		$ 0.26			$ 0.26
Employee | Incentive stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, options, grants in period, gross		20,000		0	20,000	127,558
Cost of Sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense					$ 26,000	$ 45,000
Selling, General and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense					$ 130,000	$ 139,000