Consolidated Balance Sheets (Parentheticals) - USD ($) shares in Thousands, $ in Thousands	Apr. 30, 2020	Apr. 30, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts (in Dollars)	$ 183	$ 183
Preferred stock, par value (in Dollars per share)	$ 1.00	$ 1.00
Preferred stock, shares authorized	600	600
Preferred stock, shares issued	0	0
Common stock, par value (in Dollars per share)	$ 1.00	$ 1.00
Common stock, shares authorized	20,000	20,000
Common stock shares issued	9,164	9,121
Common stock, shares outstanding	8,980	8,980
Treasury stock, shares	43	184