Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 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):

	June 30, 2023
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds	$	116,970	$	—	$	—	$	116,970
U.S. Treasury securities	—		291,289		—		291,289
U.S. government agency securities	—		94,511		—		94,511
Corporate debt securities	—		106,468		—		106,468
Total financial assets	$	116,970	$	492,268	$	—	$	609,238
Financial liabilities:
Success payment liabilities	$	—	$	—	$	3,753	$	3,753
Total financial liabilities	$	—	$	—	$	3,753	$	3,753

	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:

	June 30, 2023			December 31, 2022
Fair value of common stock	$	3.18		$	3.47
Risk-free interest rate	3.36% - 5.26%			3.58% - 4.65%
Expected volatility	80.0		%	80.0		%
Expected term (in years)	0.96 - 4.47			0.46 - 4.97

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

	June 30, 2023			December 31, 2022
Fair value of common stock	$	3.18		$	3.47
Risk-free interest rate	3.36% - 5.26%			3.58% - 4.65%
Expected volatility	80.0		%	80.0		%
Expected term (in years)	0.96 - 6.25			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 liabilities (in thousands):

	Success Payment Liabilities
Balance at December 31, 2022	$	4,356
Change in fair value (1)	(603)
Balance at June 30, 2023	$	3,753

(1)The changes in the fair value associated with the Fred Hutch success payment liabilities of approximately $(0.6) million are recorded in other (expense) income, net (See Note 3, License, Collaboration and Success Payment Agreements). The changes in the fair value of approximately zero associated with the Stanford success payment liabilities are recorded as research and development expenses.

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 liabilities (in thousands):

	Success Payment Liabilities
Balance at December 31, 2022	$	4,356
Change in fair value (1)	(603)
Balance at June 30, 2023	$	3,753

(1)The changes in the fair value associated with the Fred Hutch success payment liabilities of approximately $(0.6) million are recorded in other (expense) income, net (See Note 3, License, Collaboration and Success Payment Agreements). The changes in the fair value of approximately zero associated with the Stanford success payment liabilities are recorded as research and development expenses.