v3.25.1
Stock-Based Compensation (Tables)
3 Months Ended
Mar. 31, 2025
Stock-Based Compensation [Abstract]  
Components of Stock-Based Compensation Expense
Following is the stock-based compensation expense related to common stock options, restricted common stock, common stock warrants and deferred stock units:
         
               
    Three Months Ended
March 31,
    2025   2024
Research and development
  $ 190    $ 323 
General and administrative
    278      281 
Total stock-based compensation expense
  $ 468    $ 604 
Stock Option Activity
The following table summarizes the stock option activity in the Company’s equity incentive plans, including non-plan grants to Company executives, from December 31, 2024 through March 31, 2025:
 
         
               
    Shares    Weighted
Average
Exercise
Price
 
Outstanding, December 31, 2024
   6,854,758    $ 2.39  
Granted
   1,211,000      1.23  
Exercised
             
Options forfeited/cancelled
   (66,000     (3.45
Outstanding, March 31, 2025
   7,999,758    $ 2.20  
Weighted Average Assumptions Used to Determine Fair Value of Options Granted
The fair value of all other options granted is determined using the Black-Scholes option-pricing model. The following weighted average assumptions were used:
         
               
      Three
Months
Ended
March 31,
      Three
Months
Ended
March 31,
 
     
2025
      2024  
Risk-free interest rate
   4.48 %    4.02 %
Expected life of the options
    5.6 years       5.5 years  
Expected volatility of the underlying stock
   83 %    78 %
Expected dividend rate
   0 %    0 %