v3.25.2
Note 10 - Stock-based Compensation Expense (Tables)
6 Months Ended
Jun. 30, 2025
Notes Tables  
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]
   

Three Months Ended

June 30,

   

Six Months Ended

June 30,

 
   

2025

   

2024

   

2025

   

2024

 

Research and development

  $ 121,159     $ 40,337     $ 244,861     $ 104,134  

General and administrative

    375,856       538,244       613,321       692,662  

Total stock-based compensation expense

  $ 497,015     $ 578,581     $ 858,182     $ 796,796  
Share-Based Payment Arrangement, Option, Activity [Table Text Block]
   

Number of

Options

   

Weighted

average

exercise price

per share

   

Weighted

average

remaining

contractual life

(in years)

   

Aggregate

intrinsic value

 

Balance at January 1, 2025

    636,802     $ 19.38       7.6          

Granted

    375,400       3.63                  

Expired

    (16,828 )     60.14                  

Outstanding at June 30, 2025

    995,374     $ 12.75       7.7        

Exercisable at June 30, 2025

    449,540     $ 20.65       6.6        
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
   

Six Months Ended June 30,

 
   

2025

 

2024

 

Expected term (in years)

  5.24 - 5.76   5.25 - 5.76  

Risk-free interest rate

  3.93 - 4.35%   4.06 - 4.46%  

Expected volatility

  71.55 - 76.68%   76.87 - 80.03%  

Dividend yield

           —