v3.26.1
Stock-Based Compensation (Tables)
12 Months Ended
Dec. 31, 2025
Stock-Based Compensation  
Summary of total stock based compensation expense

The following table summarizes total stock-based compensation expense recognized for the years ended December 31, 2025 and 2024 (in thousands).

  ​ ​ ​

For the years ended

December 31, 

  ​ ​ ​

2025

  ​ ​ ​

2024

Research and development

$

1,167

$

3,112

General and administrative

40

 

344

Total stock-based compensation expense

$

1,207

$

3,456

Summary of stock option activity

The following table summarizes stock option activity for the Company’s option plans during the years ended December 31, 2025 and 2024 (in thousands, except per share amounts):

  ​ ​ ​

  ​ ​ ​

  ​ ​ ​

Weighted

  ​ ​ ​

Weighted

Average

Average

Remaining

Total

Number of

 Exercise

Contractual 

 Intrinsic

Shares

Price

Life (in years)

Value

Outstanding as of January 1, 2024

 

317,076

$

0.35

6.0

$

114,097

Granted (1)

500

 

0.53

 

3.4

 

Cashless exercised

(650)

0.35

Expired

(100)

0.83

Outstanding as of December 31, 2024

 

316,826

0.35

5.0

3,932

Granted (2)

 

2,275

 

0.29

 

5.5

 

Forfeited (3)

(7,333)

0.26

Outstanding as of December 31, 2025

311,768

$

0.35

4.0

$

10

Options vested (4)

 

278,109

$

0.33

 

4.0

$

10

(1)During the year ended December 31, 2024, the Company granted 500,000 stock options with an exercise price at $0.53 per share to a staff employee. The options vested immediately on the grant date. In addition, the Company will make an additional payment of
$0.30 per option exercised by the employee for a maximum amount of $150,000. The Company has fully accrued this additional payment as of December 31, 2025 on its consolidated balance sheets.
(2)During the year ended December 31, 2025, the Company granted 2 million stock options to a new-hire employee, of which 1.8 million options were forfeited in the same period. The Company also granted 0.3 million options to key external consultants who provide services to the Company.
(3)As part of the Advent acquisition, 5.5 million stock options that were previously issued to Advent as compensation for services were returned to the Company and cancelled. These options were fully vested as of the date of the acquisition of Advent.
(4)Of the total 278 million vested options, 183 million are subject to agreements (the “Blocker Letter Agreements”) under which they cannot be exercised except upon at least 61 days’ prior notice.
Schedule of weighted average assumptions for stock options modification

  ​ ​ ​

For the years ended

December 31, 

  ​ ​ ​

2025

  ​ ​ ​

2024

  ​ ​ ​

Exercise price

$

0.29

$

0.53

Expected term (years)

3.2

 

2.1

Expected stock price volatility

77

%  

 

73

%  

Risk-free rate

3.8

%

4.5

%

Dividend yield (per share)

0

%  

 

0

%