Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis

The following table sets forth the fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis based on the three-tier fair value hierarchy (in thousands):

	December 31, 2023
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds	$	62,075	$	—	$	—	$	62,075
U.S. Treasury securities	—		374,356		—		374,356
U.S. government agency securities	—		48,750		—		48,750
Corporate debt securities	—		59,606		—		59,606
Total financial assets	$	62,075	$	482,712	$	—	$	544,787
Financial liabilities:
Success payment liabilities	$	—	$	—	$	1,576	$	1,576
Total financial liabilities	$	—	$	—	$	1,576	$	1,576

	December 31, 2022
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds	$	67,970	$	—	$	—	$	67,970
U.S. Treasury securities	—		271,799		—		271,799
U.S. government agency securities	—		134,045		—		134,045
Corporate debt securities	—		220,681		—		220,681
Total financial assets	$	67,970	$	626,525	$	—	$	694,495
Financial liabilities:
Success payment liabilities	$	—	$	—	$	4,356	$	4,356
Total financial liabilities	$	—	$	—	$	4,356	$	4,356

Schedule of Estimated Fair Value of Success Payment Liability Assumptions

The following assumptions were incorporated into the calculation of the estimated fair value of the Fred Hutch success payment liability:

	December 31,
	2023			2022
Fair value of common stock	$	1.94		$	3.47
Risk-free interest rate	3.51% - 5.19%			3.58% - 4.65%
Expected volatility	80.0		%	80.0		%
Expected term (in years)	0.46 - 3.97			0.46 - 4.97

The following assumptions were incorporated into the calculation of the estimated fair value of the Stanford success payment liability:

	December 31,
	2023			2022
Fair value of common stock	$	1.94		$	3.47
Risk-free interest rate	3.51% - 5.19%			3.58% - 4.65%
Expected volatility	80.0		%	80.0		%
Expected term (in years)	0.46 - 5.75			0.46 - 6.75

Schedule of Changes in the Estimated Fair Value of Level 3 Financial Assets

The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial assets and liabilities (in thousands):

	Equity Warrant Investment		Success Payment Liabilities
Balance at December 31, 2021	$	1,067	$	9,486
Change in fair value (1)	(1,067)		(5,130)
Balance at December 31, 2022	—		4,356
Change in fair value (1)	—		(2,780)
Balance at December 31, 2023	$	—	$	1,576

__________

(1)The change in the fair value associated with the Fred Hutch success payment liabilities for the year ended December 31, 2023 is recorded in other income (expense), net. The change in the fair value associated with the Fred Hutch success payment liabilities for the year ended December 31, 2022, and the change in the fair value associated with the Stanford success payment liabilities for the years ended December 31, 2023 and 2022, respectively, are recorded as research and development expenses. (See Note 3, License, Collaboration and Success Payment Agreements). Changes in fair value associated with the equity warrant investment held are recorded in other income (expense), net.

Schedule of Changes in the Estimated Fair Value of Level 3 Financial Liabilities

The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial assets and liabilities (in thousands):

	Equity Warrant Investment		Success Payment Liabilities
Balance at December 31, 2021	$	1,067	$	9,486
Change in fair value (1)	(1,067)		(5,130)
Balance at December 31, 2022	—		4,356
Change in fair value (1)	—		(2,780)
Balance at December 31, 2023	$	—	$	1,576

__________

(1)The change in the fair value associated with the Fred Hutch success payment liabilities for the year ended December 31, 2023 is recorded in other income (expense), net. The change in the fair value associated with the Fred Hutch success payment liabilities for the year ended December 31, 2022, and the change in the fair value associated with the Stanford success payment liabilities for the years ended December 31, 2023 and 2022, respectively, are recorded as research and development expenses. (See Note 3, License, Collaboration and Success Payment Agreements). Changes in fair value associated with the equity warrant investment held are recorded in other income (expense), net.