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Note K - Stock Based Compensation Plan (Details) - Options valuation assumptions
12 Months Ended
Apr. 30, 2013
Apr. 30, 2012
Apr. 30, 2011
Options valuation assumptions [Abstract]      
Expected terms (years) 5 years 5 years 5 years
Risk-free interest rate 0.78% 1.48% 1.80%
Volatility 50.00% 50.00% 50.00%