v3.26.3
Stock Incentive Plans - Schedule of Stock Option Activity (Details) - 2016 Plan, 2018 Inducement Incentive Award Plan and Old Cartesian Plan
$ / shares in Units, $ in Thousands
 9 Months Ended 12 Months Ended
Sep. 30, 2026
USD ($)
$ / shares
shares
Dec. 31, 2025
USD ($)
$ / shares
shares
Number of Common Stock Options    
Beginning balance (in shares) | shares 2,463,747  
Granted (in shares) | shares 2,093,850  
Exercised (in shares) | shares (343,318)  
Forfeited (in shares) | shares (666,671)  
Ending balance (in shares) | shares 3,547,608 2,463,747
Vested (in shares) | shares 810,404  
Vested and expected to vest (in shares) | shares 3,182,104  
Weighted-average Exercise Price ($)    
Beginning balance (in dollars per share) | $ / shares $ 13.72  
Granted (in dollars per share) | $ / shares 7.22  
Exercised (in dollars per share) | $ / shares 2.30  
Forfeited (in dollars per share) | $ / shares 15.18  
Ending balance (in dollars per share) | $ / shares 10.72 $ 13.72
Vested (in dollars per share) | $ / shares 12.91  
Vested and expected to vest (in dollars per share) | $ / shares $ 10.85  
Weighted-average Remaining Contractual Term (in years)    
Outstanding, term 8 years 5 months 15 days 6 years 4 months 28 days
Vested, term 6 years 7 months 2 days  
Vested and expected to vest, term 8 years 4 months 17 days  
Aggregate Intrinsic Value    
Outstanding | $ $ 2,109 $ 2,962
Vested | $ 1,165  
Vested and expected to vest | $ $ 1,987