8. NET LOSS PER COMMON SHARE (Details - Antidilutive shares, If-Converted) - shares	3 Months Ended		9 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2019	Jan. 31, 2018
Restricted Stock Units RSUs [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	38,466	0	33,606	0
If-Converted Method [Member] | Stock Options [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	2,779,142	3,214,694	2,659,632	3,663,102
If-Converted Method [Member] | Restricted Stock Units RSUs [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	47,482	0	15,827	0
If-Converted Method [Member] | Warrants [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	0	39,040	17,115	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	1,978,783	1,978,783
If-Converted Method [Member] | Options, Warrants and Series E Preferred Stock [Member]
Antidilutive shares excluded from calculation of weighted average diluted shares outstanding	4,805,407	5,232,517	4,671,357	5,680,925