Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2022

Fair Value Disclosures [Abstract]

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, 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

	December 31, 2021
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds	$	206,245	$	—	$	—	$	206,245
U.S. Treasury securities	—		289,706		—		289,706
U.S. government agency securities	—		93,626		—		93,626
Corporate debt securities	—		285,156		—		285,156
Equity warrant investment	—		—		1,067		1,067
Total financial assets	$	206,245	$	668,488	$	1,067	$	875,800
Financial liabilities:
Success payment liabilities	$	—	$	—	$	9,486	$	9,486
Total financial liabilities	$	—	$	—	$	9,486	$	9,486

Summary 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,
	2022			2021
Fair value of common stock	$	3.47		$	7.74
Risk-free interest rate	3.58% - 4.65%			0.19% - 1.88%
Expected volatility	80.0		%	75.0		%
Expected term (in years)	0.46 - 4.97			0.46 - 5.97

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

	December 31,
	2022			2021
Fair value of common stock	$	3.47		$	7.74
Risk-free interest rate	3.58% - 4.65%			0.19% - 1.88%
Expected volatility	80.0		%	75.0		%
Expected term (in years)	0.46 - 6.75			0.46 - 7.75

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, 2020	$	1,323	$	5,773
Change in fair value (1)	(256)		3,713
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

__________

(1)The changes in fair value associated with the equity warrant investment held are recorded in other income (expense), net and the changes in fair value associated with success payment liabilities are recorded in research and development expense.

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, 2020	$	1,323	$	5,773
Change in fair value (1)	(256)		3,713
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

__________

(1)The changes in fair value associated with the equity warrant investment held are recorded in other income (expense), net and the changes in fair value associated with success payment liabilities are recorded in research and development expense.