2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details - Antidilutive shares) - shares	3 Months Ended		6 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	43,878,138	32,757,851	42,637,136	29,291,745
Stock Options [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	29,806,420	19,235,713	28,834,459	15,775,106
Due to loss position [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	165,672	1,999,164	119,972	2,380,819
Due to loss position [Member] | Stock Options [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	0	1,958,583	0	2,340,300
Due to loss position [Member] | ESPP [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	165,672	40,581	119,972	40,519