5. STOCKHOLDERS EQUITY (Details - Common stock issuances) - USD ($)	12 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Gross proceeds raised	$ 45,195,000	$ 19,235,000	$ 53,920,000
Common Stock
Number of common stock shares issued, shares	42,372,195	13,665,117	33,527,369
Gross proceeds raised	$ 45,872,000	$ 197,480,000	$ 55,424,000
December 27, 2012 Financing [Member] | Common Stock
Number of common stock shares issued, shares		3,983,360	33,527,369
Gross proceeds raised		$ 6,204,000	$ 55,424,000
June 13, 2014 Financing [Member] | Common Stock
Number of common stock shares issued, shares	8,629,738	9,681,757
Gross proceeds raised	$ 11,456,000	$ 13,544,000
August 7, 2015 Financing [Member] | Common Stock
Number of common stock shares issued, shares	6,751,651
Gross proceeds raised	$ 7,447,000
Equity Distribution Agreement [Member] | Common Stock
Number of common stock shares issued, shares	8,472,288
Gross proceeds raised	$ 6,969,000
October 30, 2015 Financing [Member] | Common Stock
Number of common stock shares issued, shares	18,518,518
Gross proceeds raised	$ 20,000,000