Note 1 - Nature of Operations and Summary of Significant Accounting Policies (Details) - Property and Equipment, Estimated Useful Lives
9 Months Ended
Jan. 31, 2014
Building and Building Improvements [Member]
 
Property, Plant and Equipment [Line Items]  
Property and equipment, useful lives 39 years
Equipment [Member] | Minimum [Member]
 
Property, Plant and Equipment [Line Items]  
Property and equipment, useful lives 3 years
Equipment [Member] | Maximum [Member]
 
Property, Plant and Equipment [Line Items]  
Property and equipment, useful lives 8 years