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Stock-based Compensation (Tables)

3 Months Ended

Mar. 31, 2023

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Summary of Stock Option Activity

A summary of the Company’s stock option activity under the 2021 Plan and 2018 Plan is as follows (in thousands, except share and per share data and years):

										Weighted-
						Weighted-				average remaining				Aggregate
						average				contractual				intrinsic
		Shares				exercise price				term (years)				value
Outstanding at December 31, 2022			17,393,396			$	5.84				8.20			$	18,295
Granted			9,025,337				4.00
Exercised			(199,344	)			0.92
Canceled			(327,118	)			5.48
Outstanding at March 31, 2023			25,892,271			$	5.24				8.61			$	8,752
Options exercisable at March 31, 2023			8,166,304			$	4.45				7.54			$	6,553

Schedule of Stock-based Compensation Expense

The allocation of stock-based compensation for all stock awards was as follows (in thousands):

		Three Months Ended March 31,
		2023				2022
Research and development		$	3,880			$	2,732
General and administrative			2,965				1,710
Total		$	6,845			$	4,442

Summary of Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consisted of the following as of March 31, 2023 and December 31, 2022:

		March 31,				December 31,
		2023				2022
Stock options issued and outstanding			25,892,271				17,393,396
Awards available for future grant			14,846,946				16,022,747
Shares available for purchase under the ESPP			2,469,614				965,131
Total			43,208,831				34,381,274

Stock Options

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Assumptions used to Determine Fair Value of Stock Option Grants and Stock to be Purchased under ESPP

The assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee and nonemployee stock option grants were as follows:

		Three Months Ended March 31,
		2023		2022
Risk-free interest rate		3.46%-4.22%		1.46%-1.74%
Expected volatility		85.52%-85.81%		85.86%-85.99%
Expected term (in years)		6.02-6.07		5.99-6.08
Expected dividend yield		--%		--%

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Tabular disclosure of allocation of amount expensed and capitalized for award under share-based payment arrangement to statement of income or comprehensive income and statement of financial position. Includes, but is not limited to, corresponding line item in financial statement.

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-Topic 718
-SubTopic 10
-Section 50
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Tabular disclosure for stock option plans. Includes, but is not limited to, outstanding awards at beginning and end of year, grants, exercises, forfeitures, and weighted-average grant date fair value.

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Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions.

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