v3.26.3
Stock-Based Compensation (Tables)
 3 Months Ended
Mar. 31, 2026
Share-Based Payment Arrangement [Abstract]  
Schedule of Weighted Average Grant Fair Value of Stock Options Using Black-Scholes Option-Pricing Model

The following table presents, on a weighted average basis, the assumptions used in the Black-Scholes option-pricing model to determine the grant-date fair value of stock options granted during the three months ended March 31, 2026 (no stock options were granted during the three months ended March 31,2025):

 

Risk-free interest rate   3.72%
Expected term (in years)   6.0 
Expected volatility   98.58%
Expected dividend yield   0%
Schedule of Stock Option Activity

The following table summarizes option activity with service and performance conditions under the 2021 Plan and the 2017 Plan:

 

   Options   Weighted Average Exercise Price   Weighted Average Contract Term   Aggregate Intrinsic Value 
Outstanding at January 1, 2026   3,941,760   $24.12           
Granted   50,000   $1.20           
Exercised   —   $—           
Forfeited/Expired   (46,048)  $3.62           
Outstanding at March 31, 2026   3,945,712   $24.07    6.2   $87,750 
Vested and expected to vest at March 31, 2026   3,945,712   $24.07    6.2   $87,750 
Exercisable at March 31, 2026   2,632,313   $34.99    4.9   $— 

 

* Options outstanding on March 31, 2026 under the 2021 Plan and 2017 Plan were 3,105,284 and 885,428, respectively, including 45,000 options with performance and service conditions.
Schedule of Activity Related to RSU Stock-Based Payment Awards

The following table summarizes activity related to RSU stock-based payment awards under the 2021 Plan:

 

  

Number of

Shares

  

Weighted

Average

Grant Date Fair Value

 
Outstanding at January 1, 2026   643,859   $4.48 
Granted   98,463   $1.30 
Vested*   (108,469)  $9.21 
Forfeited   (9,731)  $11.69 
Outstanding at March 31, 2026   624,122    3.04 
Schedule of Stock-based Compensation Expense

Stock-based compensation expense follows:

 

   2026   2025 
   3 Months Ended March 31, 
   2026   2025 
Cost of revenues  $65   $63 
Research and development   158    188 
Selling, general and administrative   1,148    2,386 
Stock-based compensation expense  $1,371   $2,637