STOCK-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Share-Based Compensation Expense Related to Stock Options

The Company recorded stock-based compensation expense in the following expense categories of its condensed statements of operations for the periods shown (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2023		2022		2023		2022
General and administrative	$	1,127	$	563	$	3,143	$	1,525
Research and development	473		277		1,368		648
Total stock-based compensation	$	1,600	$	840	$	4,511	$	2,173

Summary of Assumptions Used for Valuation of Fair Value of Stock Options

The Black-Scholes option-pricing model was used to estimate the fair value of stock options granted during the nine months ended September 30, 2023 and 2022 with the following weighted average assumptions:

	Nine Months Ended September 30,
	2023	2022
Risk-free interest rate	3.47% - 4.43%	1.71% - 4.17%
Expected term (in years)	5.5 - 6.1	5.8 - 6.1
Expected volatility	90% - 98%	90%
Expected dividend yield	0%	0%

Summary of Stock Option Activity

The following table reflects summarized stock option activity:

	Stock Options	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2023	5,610,893	$	3.36
Granted	1,921,200	$	5.96
Exercised	(111,206)	$	2.92
Forfeited	(14,489)	$	2.88
Expired	(6,251)	$	8.33
Outstanding at September 30, 2023	7,400,147	$	4.04	7.9	$	9,907
Vested and exercisable at September 30, 2023	3,621,345	$	3.02	7.2	$	7,432

Summary of Nonvested Restricted Stock Units Activity

	Number of Shares	Weighted Average Grant Date Fair Value
Unvested as of January 1, 2023	—	$	—
Granted	328,500	$	6.11
Unvested at September 30, 2023	328,500	$	6.11