Note 7 - Related Party Transactions - Non-voting Revenues Interest and Non-voting Profits Interests (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2022	Oct. 31, 2021	Oct. 31, 2022	Oct. 31, 2021
Value Line’s non-voting revenues interest	$ 2,623	$ 4,263	$ 5,405	$ 8,412
Non-voting profits interest in EAM	193	629	426	1,285
Revenues and Profits Distribution from Unconsolidated Entity	$ 2,816	$ 4,892	$ 5,831	$ 9,697