Note 7 - Related Party Transactions - Schedule of Non Voting Revenues Interest and Non Voting Profits Interests (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2017	Jul. 31, 2016
Value Line’s non-voting revenues interest	$ 1,978	$ 1,787
Non-voting profits interest in EAM	158	129
	$ 2,136	$ 1,916