v3.25.4
Stock-based compensation - Narrative (Details) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 12 Months Ended
May 31, 2025
Feb. 28, 2025
Jul. 31, 2021
Dec. 31, 2025
Dec. 31, 2024
May 31, 2023
Share-based compensation            
Granted (in shares)       1,454,250    
Stock-based compensation expense       $ 4,033 $ 3,874  
Intrinsic value of stock options exercised (less than)       $ 700 $ 100  
Weighted average grant-date fair value of stock options granted (in dollars per share)       $ 1.86 $ 0.48  
Unrecognized compensation expense       $ 1,500    
Share-Based Payment Arrangement, Option            
Share-based compensation            
Weighted average period for unrecognized compensation expense       2 years 4 months 24 days    
Restricted Stock Units (RSUs)            
Share-based compensation            
Stock-based compensation expense       $ 2,300 $ 1,600  
Weighted average grant-date fair value per share of units granted (in dollars per share)       $ 3.14 $ 0.94  
Total fair value of shares vested       $ 2,500 $ 400  
Weighted average period for unrecognized compensation expense       1 year    
Unrecognized compensation expense related to units       $ 4,500    
Restricted Stock Units (RSUs) | Minimum            
Share-based compensation            
Vesting period       1 year    
Restricted Stock Units (RSUs) | Maximum            
Share-based compensation            
Vesting period       3 years    
Class A Common stock            
Share-based compensation            
Shares available for future issuance (in shares)       28,709,681    
2010 Plan            
Share-based compensation            
Shares authorized (in shares)     0      
2021 Incentive Award Plan            
Share-based compensation            
Shares authorized (in shares)       5,158,947    
Plan term     10 years      
2021 Incentive Award Plan | Share-Based Payment Arrangement, Option | Employees, Officers and Directors            
Share-based compensation            
Granted (in shares)       1,454,250 952,470  
Stock-based compensation expense       $ 1,700 $ 2,300  
2021 Incentive Award Plan | Class A Common stock            
Share-based compensation            
Shares authorized (in shares)     4,200,000      
Percentage of aggregate number of shares outstanding     5.00%      
Maximum number of shares issuable upon exercise of stock option (in shares)     33,900,000      
2023 Inducement Plan | Class A Common stock            
Share-based compensation            
Shares available for future issuance (in shares)       660,000 217,013 330,000
Number of additional shares authorized (in shares) 442,987 476,000        
2021 ESPP            
Share-based compensation            
Plan term     10 years      
Stock-based compensation expense       $ 100 $ 100  
2021 ESPP | Options to purchase common stock under ESPP            
Share-based compensation            
Maximum percentage of payroll deduction     15.00%      
Offering period     6 months      
Maximum shares available for purchase per employee (in shares)     100,000      
Maximum value of shares available for purchase per employee     $ 25      
Discount percentage from market price     85.00%      
2021 ESPP | Class A Common stock            
Share-based compensation            
Shares authorized (in shares)     400,000      
Percentage of aggregate number of shares outstanding     1.00%      
Maximum number of shares issuable upon exercise of stock option (in shares)     6,300,000      
Shares available for future issuance (in shares)       1,170,124    
Shares purchased under plan (in shares)       164,108 287,217