v3.25.2
Stock-Based Compensation (Tables)
6 Months Ended
Jun. 30, 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
June 30,
    Six Months Ended
June 30,
 
    2025   2024     2025   2024  
    in thousands  
Research and development
  $ 254    $ 386      $ 530    $ 709   
General and administrative
    246      352        436      633   
Total stock-based compensation expense
  $ 500    $ 738      $ 966    $ 1,342   
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 June 30, 2025:
 
                
    Shares     Weighted
Average
Exercise
Price
 
Outstanding, December 31, 2024
   6,854,758     $ 2.39  
Granted
   1,211,000       1.23  
Exercised
   (346,606     2.09  
Options forfeited/cancelled
   (177,334     (2.11
Outstanding, June 30, 2025
   7,541,818     $ 2.22  
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:
        
    Six
Months
Ended
June 30,
      Six
Months
Ended
June 30,
 
   
2025
      2024  
Risk-free interest rate
 4.48 %    3.88 %
Expected life of the options
  5.6 years       5.4 years  
Expected volatility of the underlying stock
 83 %    75 %
Expected dividend rate
 0 %    0 %