v3.25.2
Note 5 - Stockholders' Equity (Deficit), Stock Option Plans, And Stock-Based Compensation (Tables)
6 Months Ended
Jun. 30, 2025
Notes Tables  
Common Stock, Capital Shares Reserved for Future Issuance [Table Text Block]

Shares underlying outstanding warrants

    81,645,868  

Shares reserved for future grants under the 2020 Equity Incentive Plan

    6,971,587  

Shares underlying outstanding stock options

    3,306,278  

Total common stock reserved for future issuance

    91,923,733  
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

Black-Scholes-Merton Inputs

       
   

Six Months Ended

June 30, 2025

 

Risk-free interest rate

    4.39 %

Expected term (in years)

    5.40  

Expected volatility

    110.24 %

Expected dividend yield

    %

Black-Scholes-Merton Inputs

       
   

Three Months

Ended June 30,

2025

 

Risk-free interest rate

    4.18 %

Expected term (in years)

    5.99  

Expected volatility

    119.00 %

Expected dividend yield

    %
Share-Based Payment Arrangement, Option, Activity [Table Text Block]
   

Shares

Available

for Grant

   

Number of

Options

Outstanding

   

Weighted

Average

Exercise

price per

share

   

Weighted

Average

Remaining

Contractual

Term in

Years

   

Aggregate

Intrinsic

Value

 

Balance, December 31, 2024

    3,060,506       2,559,440     $ 4.07       8.88     $ 683,016  

Granted

    (919,750 )     919,750       1.77                  

Expired/Cancelled

    172,912       (172,912 )     2.71                  

Evergreen Provision increase

    4,657,919                              

Balance, June 30, 2025

    6,971,587       3,306,278     $ 3.50       8.70     $  
                                         

Options vested and exercisable at June 30, 2025

      2,293,135     $ 3.93       8.50     $  
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]
   

Three Months Ended June 30,

 
   

2025

   

2024

 

Research and development

  $ 187,064     $ 184,883  

General and administrative

    208,213       174,110  

Total stock-based compensation expense

  $ 395,277     $ 358,993  
   

Six Months Ended June 30,

 
   

2025

   

2024

 

Research and development

  $ 500,926     $ 379,779  

General and administrative

    813,470       348,289  

Total stock-based compensation expense

  $ 1,314,396     $ 728,068