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Copyright Data Fees (Detail Textuals) (USD $)
12 Months Ended
Apr. 30, 2014
Contract
Apr. 30, 2013
Contract
Apr. 30, 2012
Copyright Data Fees [Abstract]      
Copyright data fees received $ 2,733,000 $ 3,900,000 $ 3,591,000
Number of contracts for copyright data 4 4  
Third party sponsored assets for copyright data $ 2,300,000,000 $ 2,700,000,000