2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details - Antidilutive shares, If-Converted) - If-Converted Method [Member] - shares	3 Months Ended		6 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Stock Options [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	3,600,478	4,258,060	3,608,917	4,119,209
ESPP [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	43,332	0	0	0
Warrants [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	39,040	39,040	39,040	39,040
Series E Preferred Stock [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	1,978,783	1,971,206	1,978,783	1,932,771
Options, ESPP, Warrants and Series E Preferred Stock [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	5,661,633	6,268,306	5,626,740	6,091,020