6. Net Loss per Common Share (Details - Antidilutive shares, conversion price) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Dilutive effect of shares on diluted shares outstanding	275	307	202	226
If Converted Method [Member]
Dilutive effect of shares on diluted shares outstanding	4,845	4,230	4,942	4,604
If Converted Method [Member] | Stock Options [Member]
Dilutive effect of shares on diluted shares outstanding	2,866	2,239	2,855	2,600
If Converted Method [Member] | RSUs [Member]
Dilutive effect of shares on diluted shares outstanding	0	0	108	0
If Converted Method [Member] | Warrants
Dilutive effect of shares on diluted shares outstanding	0	12	0	25
If Converted Method [Member] | Series E Preferred Stock [Member]
Dilutive effect of shares on diluted shares outstanding	1,979	1,979	1,979	1,979