v3.26.1
Stock Incentive Plans (Tables)
 6 Months Ended
Jun. 30, 2026
Share-Based Payment Arrangement [Abstract]  
Schedule of Stock-Based Compensation Expense
Stock-based compensation expense by classification included within the consolidated statements of operations and comprehensive income (loss), was as follows (in thousands):
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
Research and development$614 $1,810 $1,563 $3,085 
General and administrative1,469 1,469 2,943 2,702 
Total stock-based compensation expense$2,083 $3,279 $4,506 $5,787 
Schedule of Weighted Average Assumptions Used
The estimated grant date fair values of stock option awards granted under the 2016 Plan and the 2018 Inducement Incentive Award Plan were calculated using the Black-Scholes option pricing model based on the following weighted-average assumptions:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
Risk-free interest rate4.18%4.05%3.94%4.42%
Dividend yield— — — — 
Expected term (in years)6.006.155.976.20
Expected volatility89.10%95.12%92.55%97.21%
Weighted-average fair value of common stock$6.33$11.80$6.79$16.89
Schedule of Options Activity
The following table summarizes the stock option activity under the 2016 Plan, the 2018 Inducement Incentive Award Plan, and the Old Cartesian Plan for options for common stock:
Number of Common Stock Options
Weighted-average Exercise Price ($)
Weighted-average Remaining Contractual Term (in years)
Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 20252,463,747 $13.72 6.41$2,962 
Granted1,680,200 $6.68 
Reserved for issuance(10,000)$1.41 
Exercised(278,341)$2.34 
Forfeited(492,962)$14.42 
Outstanding at June 30, 20263,362,644 $11.08 8.11$8,604 
Vested at June 30, 2026974,036 $12.97 5.64$2,601 
Vested and expected to vest at June 30, 20263,013,426 $11.23 7.98$7,674 
Schedule of Restricted Stock Units Activity
The following table summarizes the Company’s restricted stock units under the 2016 Plan and the Old Cartesian Plan:
Number of Shares
Weighted-average
Grant Date
Fair Value ($)
Unvested at December 31, 2025
522,498 $18.44 
Granted420,650 6.76 
Vested(169,278)18.59 
Forfeited(125,792)13.12 
Unvested at June 30, 2026
648,078 $11.85