Quarterly report pursuant to Section 13 or 15(d)

Note 4 - Stock-based Compensation (Details Textual)

v3.21.1
Note 4 - Stock-based Compensation (Details Textual) - USD ($)
3 Months Ended 6 Months Ended
Mar. 31, 2021
Dec. 31, 2020
Mar. 31, 2020
Dec. 31, 2019
Mar. 31, 2021
Mar. 31, 2020
Share-based Payment Arrangement, Expense $ 334,178   $ 87,937   $ 623,235 $ 328,523
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total 3,182,923       $ 3,182,923  
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)         3 years 146 days  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)         105,089 116,600
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)         5 years 5 years 284 days
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)         3 years 4 years 284 days
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)         $ 23.74 $ 12.43
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)         2 years 288 days  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value 890,093       $ 890,093  
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 (in shares)   15,011   15,107    
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price (in dollars per share)   $ 11.93   $ 11.23    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)   204,612        
Share-based Payment Arrangement, Option [Member] | Minimum [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)         3 years  
Share-based Payment Arrangement, Option [Member] | Maximum [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)         5 years  
Restricted Stock [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)         39,807  
Restricted Stock [Member] | Stock Compensation Plan 2007 [Member] | Share-based Payment Arrangement, Nonemployee [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)         1 year 1 year
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)         2,120 5,830
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Intrinsic Value, Amount Per Share (in dollars per share)         $ 32.41 $ 10.72
Restricted Stock [Member] | Stock Compensation Plan 2007 [Member] | Share-based Payment Arrangement, Employee [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)         3 years  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)         37,687  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Intrinsic Value, Amount Per Share (in dollars per share)         $ 23.74  
Restricted Stock [Member] | Minimum [Member] | Stock Compensation Plan 2007 [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)         1 year  
Restricted Stock [Member] | Maximum [Member] | Stock Compensation Plan 2007 [Member]            
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)         10 years  
Selling, General and Administrative Expenses [Member]            
Share-based Payment Arrangement, Expense 313,658   83,140   $ 594,546 $ 318,928
Cost of Sales [Member]            
Share-based Payment Arrangement, Expense $ 20,520   $ 4,797   $ 28,689 $ 9,595