Note I - Stock-based Compensation - Options Exercised (Details) - USD ($) $ in Thousands	9 Months Ended
	Jan. 31, 2017	Jan. 31, 2016
Options exercised (in shares)	169,500	30,750
Cash received from option exercises	$ 1,675	$ 400
Intrinsic value of options exercised	$ 4,374	$ 943