v3.26.1
Stock Incentive Plans - Schedule of Stock Option Activity (Details) - 2016 Plan, 2018 Inducement Incentive Award Plan and Old Cartesian Plan - USD ($)
$ / shares in Units, $ in Thousands
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Number of Common Stock Options    
Beginning balance (in shares) 2,463,747  
Granted (in shares) 1,680,200  
Reserved for issuance (in shares) (10,000)  
Exercised (in shares) (278,341)  
Forfeited (in shares) (492,962)  
Ending balance (in shares) 3,362,644 2,463,747
Vested (in shares) 974,036  
Vested and expected to vest (in shares) 3,013,426  
Weighted-average Exercise Price ($)    
Beginning balance (in dollars per share) $ 13.72  
Granted (in dollars per share) 6.68  
Reserved for issuance (in dollars per share) 1.41  
Exercised (in dollars per share) 2.34  
Forfeited (in dollars per share) 14.42  
Ending balance (in dollars per share) 11.08 $ 13.72
Vested (in dollars per share) 12.97  
Vested and expected to vest (in dollars per share) $ 11.23  
Weighted-average Remaining Contractual Term (in years)    
Outstanding, term 8 years 1 month 9 days 6 years 4 months 28 days
Vested, term 5 years 7 months 20 days  
Vested and expected to vest, term 7 years 11 months 23 days  
Aggregate Intrinsic Value    
Outstanding $ 8,604 $ 2,962
Vested 2,601  
Vested and expected to vest $ 7,674