Note 10 - Stock Repurchase Program (Details Textual) - USD ($) $ in Thousands	Jul. 31, 2019	Apr. 30, 2019	Apr. 01, 2019	Apr. 30, 2018	Apr. 01, 2018
Stock Repurchase Program, Authorized Amount	$ 2,225	$ 2,225	$ 750	$ 750	$ 500