Note K - Stock-based Compensation Plans - Stock Option Plan Comparison (Details)	12 Months Ended
	Apr. 30, 2023 shares
Statement [Line Items]
Minimum exercise price as a percentage of fair market value at date of grant	100.00%
Last expiration date for outstanding options	Feb. 20, 2033
Shares available for grant at April 30, 2023 (in shares)	260,000