Issue of options under equity incentive plan - Schedule of stock option activity (Detail) (2010 Equity Incentive Plan, USD $)	24 Months Ended	30 Months Ended
	Oct. 31, 2012	Apr. 30, 2013	Oct. 31, 2010
Options Granted December 13, 2010
Number of options, outstanding at end of period	2,500,000	2,500,000	2,500,000
Weighted average exercise price, granted	$ 1	$ 1
Weighted average exercise price, outstanding end of period	$ 1	$ 1
Options Granted May 2011
Number of options, outstanding at end of period	750,000	750,000	750,000
Weighted average exercise price, granted	$ 1	$ 1
Weighted average exercise price, outstanding end of period	$ 1	$ 1