Quarterly report pursuant to Section 13 or 15(d)

Note 4 - Stock-based Compensation (Details Textual)

v3.4.0.3
Note 4 - Stock-based Compensation (Details Textual) - USD ($)
3 Months Ended 6 Months Ended
Mar. 31, 2016
Dec. 31, 2015
Mar. 31, 2015
Dec. 31, 2014
Mar. 31, 2016
Mar. 31, 2015
Selling, General and Administrative Expenses [Member]            
Allocated Share-based Compensation Expense $ 224,156   $ 280,839   $ 429,037 $ 564,466
Cost of Sales [Member]            
Allocated Share-based Compensation Expense 22,270       $ 44,156  
Minimum [Member] | Restricted Stock [Member] | Employees [Member] | Stock Compensation Plan 2007 [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period         1 year  
Maximum [Member] | Restricted Stock [Member] | Employees [Member] | Stock Compensation Plan 2007 [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period         10 years  
Restricted Stock [Member] | Employees [Member] | Stock Compensation Plan 2007 [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period         5 years 10 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period         8,500 3,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value         $ 13.64 $ 13.33
Restricted Stock [Member] | Non Employee Directors [Member] | Stock Compensation Plan 2007 [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period         1 year 1 year
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period         2,712 3,705
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value         $ 14.73 $ 13.48
Restricted Stock [Member] | Outgoing Non Employee Directors [Member] | Stock Compensation Plan 2007 [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period         1,356  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value         $ 14.73  
Restricted Stock [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period         12,568  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value         $ 13.99  
Employee Stock Purchase Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Market Price Percentage, Offering Date         85.00%  
Stock Issued During Period, Shares, Employee Stock Purchase Plans   10,352   10,097    
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price   $ 11.40   $ 10.46    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant   155,088        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross         0 0
Allocated Share-based Compensation Expense $ 246,426       $ 473,193  
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized     $ 3,959,018     $ 3,959,018
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition           8 years 219 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term 1 year 73 days          
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value $ 2,608,019       2,608,019  
Proceeds from Stock Options Exercised $ 84,738       $ 84,738 $ 28,967
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period         57,050 40,000