Note 6 - Net Income Per Share (Details)
3 Months Ended 9 Months Ended
Jan. 31, 2014
Jan. 31, 2013
Jan. 31, 2014
Jan. 31, 2013
Earnings Per Share [Abstract]        
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 10,000 223,750 10,000 201,750