Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2024

Stock-Based Compensation [Abstract]

Weighted-Average Assumptions for Stock Options

The weighted average assumptions that the Company used in a Black-Scholes pricing model to determine the fair value of stock options granted to employees, non-employees and directors were as follows:

	Six Months Ended June 30,
	2024			2023
Risk-free interest rate		4.94	%		3.96	%
Expected term (in years)		5.82			5.84
Expected volatility		73.69	%		73.42	%
Expected dividend yield		0.00	%		0.00	%
Exercise price	$	27.90		$	20.20
Fair value of common stock	$	27.90		$	20.20

Stock Option Activity

The following table summarizes stock option activity for the six months ended June 30, 2024:

				Weighted		Weighted
				Average		Average		Aggregate
	Number of			Exercise		Contractual		Intrinsic
	Shares			Price		Term (Years)		Value
Outstanding as of December 31, 2023		14,863,996		$	15.07		5.16	$	250,602
Granted		1,595,074			27.90		9.63
Exercised		(233,100	)		11.64				3,249
Cancelled or forfeited		(119,813	)		24.83
Outstanding as of June 30, 2024		16,106,157		$	16.31		5.15	$	136,365
Options vested and exercisable as of June 30, 2024		12,735,361		$	14.46		4.12	$	131,840
Options unvested as of June 30, 2024		3,370,796		$	23.34		9.03	$	4,525

RSU Activity

The following table summarizes the Company’s RSU activity for the six months ended June 30, 2024:

				Weighted Average
	Number of			Grant Date
	Shares			Fair Value
Unvested as of December 31, 2023		1,490,357		$	18.53
Granted		694,940			28.34
Vested		(441,246	)		18.99
Forfeited		(59,898	)		18.95
Unvested as of June 30, 2024		1,684,153		$	22.44

PSU Activity

The following table summarizes the Company’s PSU activity for six months ended June 30, 2024:

			Weighted Average
	Number of		Grant Date
	Shares		Fair Value
Unvested as of December 31, 2023		-	$	-
Granted		156,738		27.93
Vested		-		-
Forfeited		-		-
Unvested as of June 30, 2024		156,738	$	27.93

PSU vesting and expense recognition is based on achievement of specific performance goals within certain time periods. PSU awards that are not achieved within specific time periods are forfeited. No performance goals were probable of achievement and no time periods had expired as of June 30, 2024.

Stock-Based Compensation Expense by Award Type

Stock-based compensation expense recognized by award type was as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Stock options	$	7,162	$	7,455	$	14,100	$	14,440
Restricted stock units		4,170		2,790		7,484		4,720
Total stock-based compensation expense	$	11,332	$	10,245	$	21,584	$	19,160

Stock-Based Compensation Expense

Stock-based compensation expense by classification included within the Consolidated Statements of Operations and Comprehensive Loss was as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Research and development	$	4,885	$	4,638	$	9,522	$	8,457
General and administrative		6,447		5,607		12,062		10,703
Total stock-based compensation expense	$	11,332	$	10,245	$	21,584	$	19,160