Schedule of Share-based Compensation, Stock Options, Activity (Details)	3 Months Ended
	Jul. 31, 2015 USD ($)
Common Stock Schedule Of Share-based Compensation, Stock Options, Activity 1	$ 4,117,812
Common Stock Schedule Of Share-based Compensation, Stock Options, Activity 2	1.52
Common Stock Schedule Of Share-based Compensation, Stock Options, Activity 3	579,000
Common Stock Schedule Of Share-based Compensation, Stock Options, Activity 4	0.50
Common Stock Schedule Of Share-based Compensation, Stock Options, Activity 5	(193,854)
Common Stock Schedule Of Share-based Compensation, Stock Options, Activity 6	1.16
Common Stock Schedule Of Share-based Compensation, Stock Options, Activity 7	4,502,958
Common Stock Schedule Of Share-based Compensation, Stock Options, Activity 8	1.41
Common Stock Schedule Of Share-based Compensation, Stock Options, Activity 9	2,290,006
Common Stock Schedule Of Share-based Compensation, Stock Options, Activity 10	1.75
Common Stock Schedule Of Share-based Compensation, Stock Options, Activity 11	2,105,439
Common Stock Schedule Of Share-based Compensation, Stock Options, Activity 12	$ 1.77