Other Comprehensive Income (Loss) (Details) - Schedule of Accumulated Other Comprehensive Income (Loss) - USD ($) $ in Thousands		12 Months Ended
		Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Schedule of Accumulated Other Comprehensive Income (Loss) [Abstract]
Balance, Change in Market Value of Marketable Securities		$ 291	$ 490	$ 46
Items of other comprehensive income (loss) before reclassification, pretax		(171)	443
Tax effect		(6)	0
Items of other comprehensive income (loss) before reclassification, net of taxes		(177)	443
Reclassification adjustments, pretax **	[1]	(28)	1
Tax effect		6
Tax effect		(22)	1
Total other comprehensive income (loss), net of taxes		$ (199)	$ 444

[1] The reclassification adjustments represent net realized gains on the sale or redemption of available-for-sale marketable securities that were reclassified from AOCI to Other income (expense), net.