Stock Incentive Plans (Tables)

3 Months Ended

Mar. 31, 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 loss, was as follows (in thousands):


	Three Months Ended March 31,
	2026		2025
Research and development	$	949	$	1,275
General and administrative	1,474		1,233
Total stock-based compensation expense	$	2,423	$	2,508

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 March 31,
	2026			2025
Risk-free interest rate	3.93		%	4.46		%
Dividend yield	—			—
Expected term (in years)	5.97			6.20
Expected volatility	92.71		%	97.44		%
Weighted-average fair value of common stock	$	6.81		$	17.46

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, 2025	2,463,747	$	13.72	6.41	$	2,962
Granted	1,304,450	$	6.81
Exercised	(86,132)	$	3.25
Forfeited	(139,658)	$	15.90
Outstanding at March 31, 2026	3,542,407	$	11.34	7.74	$	2,002

Vested at March 31, 2026	1,204,110	$	11.35	5.11	$	1,926
Vested and expected to vest at March 31, 2026	3,139,038	$	11.33	7.64	$	2,002

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
Granted	420,650	6.76
Vested	(169,278)	18.59

Forfeited	(37,598)	16.61
Unvested at March 31, 2026	736,272	$	11.82