Concentrations of credit risk - Additional Information (Detail) (USD $)	9 Months Ended	3 Months Ended		9 Months Ended			12 Months Ended	3 Months Ended	9 Months Ended
	Jul. 31, 2014	Jul. 31, 2014 Sales Revenue, Goods, Net	Jul. 31, 2013 Sales Revenue, Goods, Net	Jul. 31, 2014 Sales Revenue, Goods, Net	Jul. 31, 2013 Sales Revenue, Goods, Net	Jul. 31, 2014 Accounts Receivable	Oct. 31, 2013 Accounts Receivable	Jul. 31, 2014 Optiflex Customer Concentration Risk	Jul. 31, 2014 Optiflex Customer Concentration Risk
Concentration Risk [Line Items]
Cash, FDIC insured amount	$ 13,500,000
Concentration risk, percentage		34.00%	55.00%	33.00%	53.00%	29.00%	27.00%	7.00%	11.00%
Concentration agreement with major customer	15 years
Sales revenue, goods, net								$ 388,000	$ 1,800,000