7. Net Income (Loss) per Common Share (Details - Reconcilation of per share) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Earnings Per Share [Abstract]
Net income (loss)	$ 2,207	$ (2,104)	$ 9,221	$ (5,698)
Series E preferred stock accumulated dividends	(1,442)	(1,442)	(3,604)	(3,604)
Net income (loss) attributable to common stockholders	$ 765	$ (3,546)	$ 5,617	$ (9,302)
Weighted average common shares outstanding, basic	58,865	56,404	57,349	56,275
Stock options	937	0	507	0
RSUs	279	0	188	0
ESPP	16	0	14	0
Weighted average common shares outstanding, dilutive	60,097	56,404	58,058	56,275
Net income (loss) per share, basic	$ 0.01	$ (0.06)	$ 0.10	$ (0.17)
Net income (loss) per share, diluted	$ 0.01	$ (0.06)	$ 0.10	$ (0.17)