Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2024

Share-Based Payment Arrangement [Abstract]

Summary of Stock-Based Compensation Expense

Total stock-based compensation expense recognized was as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Research and development	$	2,671	$	2,381	$	5,211	$	4,587
General and administrative		3,333		2,642		6,472		5,201
Total stock-based compensation	$	6,004	$	5,023	$	11,683	$	9,788

Summary of Stock Option Activity

Stock Options

A summary of stock option activity for the six months ended June 30, 2024 is set forth below:

	Number of Shares Underlying Outstanding Options			Weighted Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding, December 31, 2023		9,383,105		$	10.64		8.2	$	45
Options granted		7,149,453		$	2.53
Options exercised		(92,283	)	$	2.12
Options forfeited or cancelled		(285,610	)	$	8.55
Outstanding, June 30, 2024		16,154,665		$	7.14		8.6	$	—
Options exercisable, June 30, 2024		5,602,588		$	11.95		7.4	$	—
Vested and expected to vest, June 30, 2024		16,154,665		$	7.14		8.6	$	—

Schedule of Assumptions to Estimate Fair Value of Stock Options Using Black-Scholes Option Pricing Model

The assumptions used in the Black-Scholes option-pricing model to calculate stock-based compensation are as follows:

	Three Months Ended June 30,		Six Months Ended June 30,
	2024	2023	2024	2023
Fair value of common stock	$1.21 - $1.45	$2.43 - $5.84	$1.21 - $3.12	$2.43 - $9.15
Expected term (years)	5.5 - 6.1	5.5 - 6.1	5.5 - 6.1	5.5 - 6.1
Volatility	84.1% - 85.1%	84.6% - 86.5%	82.2% - 85.1%	83.3% - 86.5%
Risk free rates	4.3% - 4.5%	3.5% - 4.1%	3.9% - 4.5%	3.5% - 4.2%
Dividend rate	0.0%	0.0%	0.0%	0.0%

Summary of Restricted Stock Unit Activity

The summary of RSU activity and related information for the six months ended June 30, 2024 is set forth below:

	Number of Units Outstanding			Weighted Average Grant Date Fair Value
Outstanding, December 31, 2023		454,200		$	7.69
RSUs granted		529,600		$	2.62
RSUs vested		(184,380	)	$	7.15
RSUs forfeited		(16,632	)	$	4.42
Outstanding, June 30, 2024		782,788		$	4.42