v3.25.4
Stock-based compensation (Tables)
12 Months Ended
Dec. 31, 2025
Stock-based compensation  
Summary of compensation cost recognized for all stock-based compensation awards

Year ended December 31, 

 

  ​ ​ ​

2025

  ​ ​ ​

2024

  ​ ​ ​

2023

 

(in thousands)

 

Research and development

$

6,138

$

6,039

$

3,585

General and administrative

 

8,649

 

8,746

 

7,568

Total stock-based compensation expense

$

14,787

$

14,785

$

11,153

Summary of status and changes in unvested restricted stock and performance-based restricted stock units

  ​ ​ ​

Weighted

Average

Grant Date

Fair Value

Units

  ​ ​ ​

Per Unit

Unvested restricted stock units as of December 31, 2024

1,649,943

$

7.44

Awarded

1,854,011

$

4.22

Vested

(691,107)

$

7.02

Forfeited

(515,927)

$

5.64

Unvested restricted stock units as of December 31, 2025

2,296,920

$

5.39

Summary of stock option activity

  ​ ​ ​

Weighted

  ​ ​ ​

Remaining

  ​ ​ ​

Aggregate

Average

Contractual

Intrinsic

Exercise

Life

Value

Shares

  ​ ​ ​

Price

  ​ ​ ​

(in years)

  ​ ​ ​

(in thousands)

Outstanding at December 31, 2024

8,800,464

$

8.10

 

7.3

3,462

Granted

2,302,270

$

4.10

Exercised

(91,489)

$

2.92

Cancelled or forfeited

(1,397,364)

$

7.15

Outstanding at December 31, 2025

9,613,881

$

7.26

6.8

1,251

Exercisable at December 31, 2025

6,357,031

$

8.01

 

5.8

$

973

Summary of weighted-average assumptions

Year ended December 31, 

  ​ ​ ​

2025

  ​ ​ ​

2024

  ​ ​ ​

2023

Risk-free interest rate

 

4.2

%  

 

4.1

%  

 

4.0

%

Expected dividend yield

 

%

 

%

 

%

Expected term (in years)

 

6.0

 

6.0

 

6.0

Expected volatility

 

75.5

%  

 

76.3

%  

 

80.4

%