8. Net Income (Loss) Per Common Share (Details - Antidilutive shares) - shares shares in Thousands	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Dilutive effect of shares on diluted shares outstanding	3,621	4,864	4,922
Stock Options
Dilutive effect of shares on diluted shares outstanding	829	2,795	2,851
RSUs [Member]
Dilutive effect of shares on diluted shares outstanding	0	83	68
Employee Stock Purchase Plan [Member]
Dilutive effect of shares on diluted shares outstanding	0	7	11
Warrants
Dilutive effect of shares on diluted shares outstanding	0	0	13
Series E Preferred Stock [Member]
Dilutive effect of shares on diluted shares outstanding	1,864	1,979	1,979
Convertible Senior Notes [Member]
Dilutive effect of shares on diluted shares outstanding	928	0	0