Quarterly report pursuant to Section 13 or 15(d)

Note 4 - Stock-based Compensation (Details Textual)

v3.8.0.1
Note 4 - Stock-based Compensation (Details Textual) - USD ($)
3 Months Ended 6 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Mar. 31, 2017
Dec. 31, 2016
Mar. 31, 2018
Mar. 31, 2017
Allocated Share-based Compensation Expense, Total $ 485,794   $ 590,165   $ 969,081 $ 1,183,911
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total 3,999,219       $ 3,999,219  
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition         6 years 219 days  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross         0 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term         2 years 146 days  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value 339,012       $ 339,012  
Proceeds from Stock Options Exercised         $ 17,949 $ 28,459
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period         6,100 15,750
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   14,242   11,144    
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price   $ 10.41   $ 15.21    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant   103,013        
Restricted Stock [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period         4,235  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value         $ 14.75  
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         4,235 3,795
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value         $ 14.75 $ 16.45
Minimum [Member] | Restricted Stock [Member] | Employee and Non-Employee Directors [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] | Employee and Non-Employee Directors [Member] | Stock Compensation Plan 2007 [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period         10 years  
Selling, General and Administrative Expenses [Member]            
Allocated Share-based Compensation Expense, Total 443,763   535,464   $ 885,020 $ 1,074,510
Cost of Sales [Member]            
Allocated Share-based Compensation Expense, Total $ 42,031   $ 54,701   $ 84,061 $ 109,401