Business acquisitions - Additional Information (Detail) - USD ($)		1 Months Ended	12 Months Ended
	May 19, 2015	Jan. 20, 2017	Oct. 31, 2016	Oct. 31, 2015	Jun. 05, 2015
Payments to Acquire Businesses, Gross			$ 2,100,000
Revenues			30,241,000	$ 30,908,000
Selling, General and Administrative Expense			9,560,000	8,888,000
Accrued Earn Out Liability			707,000	1,150,000
Rel-Tech Electronics, Inc
Business Acquisition, Additional Payment In Cash			$ 800,000
Business Acquisition Unregistered Common Stock Shares			50,467
Description For President Annual Bonus			318,000
Business Acquisition Unregistered Common Stock Value			$ 200,000
Business Acquisition, Percentage of Voting Interests Acquired					100.00%
Payments to Acquire Businesses, Gross			$ 3,100,000
Business Acquisition, Share Price			$ 3.96
Revenues			$ 6,800,000	3,100,000
Selling, General and Administrative Expense			154,000
Accrued Earn Out Liability Current			322,000
Accrued Earn Out Liability			450,000
Accrued Earn Out Liability Non Current			128,000
Rel-Tech Electronics, Inc | Palumbo
Salary Payable To President			$ 150,000
Description For President Annual Bonus			earn an annual bonus of up to 50% of his base salary.
CompPro Product Line
Business Acquisition Cost Of Acquired Entity Purchase Price value	$ 700,000
Payments to Acquire Businesses, Gross	700,000
Business Acquisition Cost Of Acquired Entity Purchases Price	$ 700,000
Comnet Telecom Supply Inc
Business Acquisition Cost Of Acquired Entity Purchase Price value			$ 1,060,000
Business Acquisition Unregistered Common Stock Shares			252,381
Business Acquisition, Percentage of Voting Interests Acquired			100.00%
Payments to Acquire Businesses, Gross			$ 3,090,000
Business Acquisition, Share Price			$ 4.20
Revenues			$ 9,100,000	10,300,000
Business Acquisition Cost Of Acquired Entity Purchases Price			4,150,000
Selling, General and Administrative Expense			56,000	$ 318,000
Accrued Earn Out Liability Current			385,000
Escrow Deposit Disbursements Related to Property Acquisition			300,000
Comnet Telecom Supply Inc | Mr. Portera
Business Acquisition Cost Of Acquired Entity Purchase Price value			4,150,000
Business Acquisition, Additional Payment In Cash			$ 1,360,000
Description For President Annual Bonus			earn an annual bonus of up to 50% of his base salary.
Business Combination, Consideration Transferred		$ 210,000