Income taxes (Detail) (U.S. Internal Revenue Service [Member], USD $)	3 Months Ended
	Jan. 31, 2013
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	1,405,000
Minimum [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, expiration year	2028
Maximum [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, expiration year	2031