Note 4 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Current Income Tax Expense (Benefit), Total	$ 1,594	$ 297
Current Federal Tax Expense (Benefit)	1,151	170
Current State and Local Tax Expense (Benefit)	443	$ 127
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total	$ 0