Note 5 - Accounts Receivable, Net, Contract Asset and Contract Liability (Details Textual) - USD ($) $ in Thousands	9 Months Ended
	Jan. 31, 2023	Jan. 23, 2023	Jan. 23, 2022	Apr. 30, 2022
Accounts Receivable, after Allowance for Credit Loss, Total	$ 4,754			$ 3,636
Accounts Receivable, Allowance for Credit Loss, Ending Balance	205			205
Contract with Customer, Asset, after Allowance for Credit Loss, Total	2,722			$ 1,470
Increase (Decrease) in Contract with Customer, Asset	1,252	$ 1,252	$ 1,191
Increase (Decrease) in Contract with Customer, Liability	$ 4,043	$ 4,043	$ (4,742)