9. NET LOSS PER COMMON SHARE (Details - Antidilutive shares, If-Converted) - shares	3 Months Ended
	Jul. 31, 2018	Jul. 31, 2017
Stock Options, Unvested Restricted Stock Rights, Common Stock Shares [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	112,225
If-Converted Method [Member] | Stock Options [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	2,694,732	3,602,628
If-Converted Method [Member] | Warrants [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	39,040	39,040
If-Converted Method [Member] | Series E Preferred Stock [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	1,978,783	1,978,783
If-Converted Method [Member] | Options, ESPP, Warrants and Series E Preferred Stock [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	4,712,555	5,620,451