Note 5 - Accounts Receivable, Net, Contract Asset and Contract Liability (Details Textual) - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2022	Oct. 31, 2021	Jul. 31, 2022	Apr. 30, 2022
Accounts Receivable, after Allowance for Credit Loss, Total	$ 3,960			$ 3,636
Accounts Receivable, Allowance for Credit Loss, Ending Balance			$ 205	205
Contract with Customer, Asset, after Allowance for Credit Loss, Total	1,242			$ 1,470
Increase (Decrease) in Contract with Customer, Asset	(228)	$ 680
Increase (Decrease) in Contract with Customer, Liability	$ 4,028	$ (4,553)