Annual report pursuant to Section 13 and 15(d)

Note C - Shareholders' Equity (Details Textual)

v3.10.0.1
Note C - Shareholders' Equity (Details Textual) - USD ($)
3 Months Ended 12 Months Ended
Jun. 30, 2018
Dec. 31, 2017
Jun. 30, 2017
Dec. 31, 2016
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2016
Common Stock, Shares Authorized         50,000,000 50,000,000  
Common Stock, Par or Stated Value Per Share         $ 0.01 $ 0.01  
Preferred Stock, Shares Authorized         500,000 500,000  
Preferred Stock, Shares Issued, Total         0 0  
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant         1,003,644    
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total         $ 3,522,909    
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition         6 years 36 days    
Allocated Share-based Compensation Expense, Total         $ 2,003,207 $ 2,319,975 $ 1,404,899
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross         108,000 0 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Remaining Contractual Term         4 years 255 days    
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period         3 years    
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price         $ 13.37  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value         $ 4.78    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term         1 year 324 days 2 years 266 days  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number           0 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period         8,450 15,850  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value         $ 75,767 $ 237,172  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value         $ 331,535    
Stock Repurchased During Period, Shares         41,989 75,445  
Treasury Stock Acquired, Average Cost Per Share         $ 11.66 $ 12.63  
Payments Related to Tax Withholding for Share-based Compensation         $ 489,428 $ 952,832 $ 437,537
Preferred Stock, Shares Outstanding, Ending Balance         0 0  
Employee Stock Purchase Plan [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant 87,081            
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 15,932 14,242 14,723 11,144      
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price $ 9.39 $ 10.41 $ 11.22 $ 15.21      
Payments Related to Tax Withholding for Share-based Compensation         $ 70,905    
Director [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term         6 years    
Employee Stock Option [Member] | Director [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period         1 year    
Employee Stock Option [Member] | Minimum [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period         3 years    
Employee Stock Option [Member] | Maximum [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period         5 years    
Cashless Method Stock Option Exercised [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period         2,250 10,500  
Restricted Stock [Member] | Minimum [Member] | Employees [Member] | Stock Compensation Plan 2007 [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period         1 year    
Restricted Stock [Member] | Maximum [Member] | Employees [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         $ 1,835,086 $ 2,103,621 1,272,656
Cost of Sales [Member]              
Allocated Share-based Compensation Expense, Total         $ 168,121 $ 216,354 $ 132,243
Undesignated Shares [Member]              
Preferred Stock, Shares Authorized         5,000,000    
Series B Preferred Stock [Member]              
Preferred Stock, Shares Authorized         500,000    
Preferred Stock, Shares Issued, Total         0    
Preferred Stock, Shares Outstanding, Ending Balance         0