Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) - $ / shares	Jan. 31, 2016	Apr. 30, 2015
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	12,724,601	12,688,890
Common stock, shares outstanding (in shares)	8,222,763	8,529,223
Treasury stock, shares (in shares)	4,501,838	4,159,667