v3.23.1
Note 8 - Stock-based Compensation (Tables)
3 Months Ended
Mar. 31, 2023
Notes Tables  
Share-Based Payment Arrangement, Option, Activity [Table Text Block]
           

Weighted-

 
           

Average

 
   

Stock Options

   

Exercise Price

 

Options outstanding at December 31, 2022

    263,992     $ 79.07  

Granted

    134,647       33.84  

Exercised

    -       -  

Forfeited

    (15,061 )     73.17  

Expired

    (672 )     108.33  

Options outstanding at March 31, 2023

    382,906     $ 63.34  
                 

Exercisable at March 31, 2023

    120,344     $ 89.42  
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
   

Three Months Ended March 31,

 
   

2023

   

2022

 

Risk-free interest rate

   

3.90% - 4.55%

     

1.94%

 

Expected life (years)

    2.00 - 6.25       6.25  

Expected volatility

   

49.23% - 55.92%

     

45.95%

 

Expected dividend yield

   

0%

     

0%

 
Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]
           

Weighted-

 
           

Average

 
           

Grant Date

 
   

Restricted

   

Fair Value

 
   

Stock

   

Per Share

 

Restricted stock at December 31, 2022

    478,596     $ 70.36  

Granted

    88,658       33.84  

Restrictions lapsed

    (37,528 )     111.56  

Forfeited

    (23,807 )     75.18  

Restricted stock at March 31, 2023

    505,919     $ 60.57  
Schedule of Nonvested Performance-Based Units Activity [Table Text Block]
           

Weighted-

 
           

Average

 
           

Grant Date

 
   

Performance

   

Fair Value

 
   

Stock

   

Per Share

 

Performance stock at December 31, 2022

    35,802     $ 77.91  

Granted

    71,295       57.79  

Restrictions lapsed

    -       -  

Performance change

    -       -  

Forfeited

    -       -  

Performance stock at March 31, 2023

    107,097     $ 74.08  
Schedule of Share-based Payment Award, Awards Other Than Stock Options, Valuation Assumptions [Table Text Block]
   

Three Months Ended March 31,

 
   

2023

   

2022

 

Risk-free interest rate

   

4.35%

     

1.76%

 

Expected life (years)

    2.88       2.87  

Expected volatility

   

58.00%

     

53.50%

 

Expected dividend yield

   

0%

     

0%

 
Schedule of Share-Based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]
   

Three Months Ended March 31,

 
   

2023

   

2022

 

Risk-free interest rate

   

4.60%

     

0.17%

 

Expected life (months)

    6.00       6.00  

Expected volatility

   

67.84%

     

53.44%

 

Expected dividend yield

   

0%

     

0%