7. Net Income (Loss) per Common Share (Details - Antidilutive shares) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Dilutive effect of shares on diluted shares outstanding	2,304	4,085	3,650	4,708
Stock Options
Dilutive effect of shares on diluted shares outstanding	325	2,106	1,665	2,721
RSUs [Member]
Dilutive effect of shares on diluted shares outstanding	0	0	4	8
ESPP [Member]
Dilutive effect of shares on diluted shares outstanding	0	0	2	0
Series E Preferred Stock [Member]
Dilutive effect of shares on diluted shares outstanding	1,979	1,979	1,979	1,979