Note 5 - Stockholders' Equity (Details) (USD $)
3 Months Ended 9 Months Ended 12 Months Ended
Jan. 31, 2014
Jan. 31, 2014
Jan. 31, 2013
Dec. 17, 2012
Apr. 30, 2013
Note 5 - Stockholders' Equity (Details) [Line Items]          
Share Repurchase Program, Repurchase Percentage       10.00%  
Share Repurchase Program, Shares to be Repurchased       400,000  
Stock Repurchased During Period, Shares 27,407 98,767      
Stock Repurchased During Period, Value (in Dollars) $ 220,000 $ 703,000      
Stock Repurchased During the Period, Cost Per Share (in Dollars per share) $ 8.03 $ 7.14      
Share Based Compensation, Number Of Plans 2 2      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number 260,967 260,967     205,500
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options (in Dollars)   61,000      
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized (in Dollars) 340,000 340,000      
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition   2 years 36 days      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value (in Dollars) 2,320,000 2,320,000      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value (in Dollars) 1,268,000 1,268,000      
Share-based Compensation (in Dollars)   $ 142,000 $ 89,000    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)   $ 4.84      
Restricted Stock [Member] | 2010 Equity Incentive Plan [Member]
         
Note 5 - Stockholders' Equity (Details) [Line Items]          
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number 11,146 11,146      
Restricted Stock [Member]
         
Note 5 - Stockholders' Equity (Details) [Line Items]          
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)   $ 5.86      
1991 Stock Option Plan [Member]
         
Note 5 - Stockholders' Equity (Details) [Line Items]          
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized 675,000 675,000      
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period   10 years      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number 93,000 93,000      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant 27,000 27,000      
1991 Stock Option Plan [Member] | Minimum [Member]
         
Note 5 - Stockholders' Equity (Details) [Line Items]          
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period   1 year      
1991 Stock Option Plan [Member] | Maximum [Member]
         
Note 5 - Stockholders' Equity (Details) [Line Items]          
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period   5 years      
2010 Equity Incentive Plan [Member]
         
Note 5 - Stockholders' Equity (Details) [Line Items]          
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized 380,000 380,000      
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period   10 years      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number 167,967 167,967      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant 189,651 189,651