Annual report pursuant to Section 13 and 15(d)

Note C - Shareholders' Equity (Details Textual)

v3.19.3
Note C - Shareholders' Equity (Details Textual) - USD ($)
6 Months Ended 12 Months Ended
Apr. 25, 2017
Jun. 30, 2019
Dec. 31, 2018
Jun. 30, 2018
Dec. 31, 2017
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2017
Nov. 13, 2014
Stock Repurchase Program, Remaining Authorized Repurchase Amount           $ 5,409,326     $ 8,000,000
Stock Repurchase Program, Increase in Authorized Amount $ 4,000,000                
Stock Repurchase Program, Authorized Amount $ 12,000,000                
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           851,134      
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total           $ 2,371,309      
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition           4 years 328 days      
Share-based Payment Arrangement, Expense           $ 1,729,025 $ 2,003,207 $ 2,319,975  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross           172,000 108,000 0  
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period           4 years      
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period           3 years 3 years    
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price           $ 12.17 $ 13.37    
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, Options, Exercisable, Weighted Average Remaining Contractual Term           2 years 146 days 1 year 324 days    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number           36,000 0    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period           7,750 8,450    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value           $ 81,728 $ 75,767    
Stock Repurchased During Period, Shares           40,933 41,989    
Treasury Stock Acquired, Average Cost Per Share           $ 13.51 $ 11.66    
Payment, Tax Withholding, Share-based Payment Arrangement           $ 553,165 $ 489,428 $ 952,832  
Employee Stock Purchase Plan [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant   49,846              
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   19,923 17,312 15,932 14,242        
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price   $ 8.43 $ 8.43 $ 9.39 $ 10.41        
Payment, Tax Withholding, Share-based Payment Arrangement           $ 80,708      
Director [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term           6 years      
Share-based Payment Arrangement, Option [Member] | Director [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period           1 year      
Share-based Payment Arrangement, Option [Member] | Minimum [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period           3 years      
Share-based Payment Arrangement, 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           6,750 2,250    
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]                  
Share-based Payment Arrangement, Expense           $ 1,638,829 $ 1,835,086 2,103,621  
Cost of Sales [Member]                  
Share-based Payment Arrangement, Expense           $ 90,196 $ 168,121 $ 216,354  
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