7. EQUITY COMPENSATION PLANS (Details - Share based compensation) - USD ($)	3 Months Ended		6 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Share based compensation	$ 309,000	$ 885,000	$ 794,000	$ 1,722,000
Cost of contract manufacturing [Member]
Share based compensation	138,000	24,000	138,000	66,000
Selling, general and administrative [Member]
Share based compensation	135,000	415,000	351,000	840,000
Research and development [Member]
Share based compensation	36,000	446,000	305,000	816,000
Stock Options [Member]
Share based compensation	287,000	823,000	696,000	1,554,000
ESPP [Member]
Share based compensation	$ 22,000	$ 62,000	$ 98,000	$ 168,000