Fair Value Measurements and Fair Value of Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2022

Fair Value Disclosures [Abstract]

Schedule of Financial Instruments Measured on Recurring Basis

The following table sets forth our financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):

	Fair Value Measurements as of September 30, 2022
	Total		Level 1		Level 2		Level 3
Assets:
Commercial paper ($52,821 included in cash and cash equivalents)	$	149,970	$	—	$	149,970	$	—
U.S. Treasury bills	87,863		87,863		—		—
Corporate debt securities	46,635		—		46,635		—
Money market fund investments (included in cash and cash equivalents)	29,264		29,264		—		—
U.S. government agency bonds	28,858		—		28,858		—
Total fair value of assets	$	342,590	$	117,127	$	225,463	$	—
Liabilities:
MSKCC success payments liability	$	3,039	$	—	$	—	$	3,039
Total fair value of liabilities	$	3,039	$	—	$	—	$	3,039

	Fair Value Measurements as of December 31, 2021
	Total		Level 1		Level 2		Level 3
Assets:
Money market fund investments (included in cash and cash equivalents)	$	181,528	$	181,528	$	—	$	—
Commercial paper ($58,892 included in cash and cash equivalents)	141,676		—		141,676		—
Corporate debt securities	38,649		—		38,649		—
U.S. Treasury bills	26,590		26,590		—		—
U.S. government agency bonds	25,065		—		25,065		—
Total fair value of assets	$	413,508	$	208,118	$	205,390	$	—
Liabilities:
MSKCC success payments liability	$	4,080	$	—	$	—	$	4,080
Total fair value of liabilities	$	4,080	$	—	$	—	$	4,080

Schedule of Fair Value and Amortized Cost of Cash Equivalents and Available-for-Sale Marketable Securities

The fair value and amortized cost of cash equivalents and available-for-sale marketable securities by major security type as of September 30, 2022 and December 31, 2021 are presented in the following tables (in thousands):

	As of September 30, 2022
	Amortized Cost Basis		Unrealized Gains		Unrealized Losses		Estimated Fair Value
Commercial paper ($52,821 included in cash and cash equivalents)	$	150,135	$	—	$	(165)	$	149,970
U.S. Treasury bills	89,027		—		(1,164)		87,863
Corporate debt securities	47,022		—		(387)		46,635
Money market investments (included in cash equivalents)	29,264		—		—		29,264
U.S. government agency bonds	29,178		1		(321)		28,858
Total cash equivalents and marketable securities	$	344,626	$	1	$	(2,037)	$	342,590
Classified as:
Cash and cash equivalents							$	82,085
Marketable securities, short-term							211,284
Marketable securities, long-term							49,221
Total cash equivalents and marketable securities							$	342,590

	As of December 31, 2021
	Amortized Cost Basis		Unrealized Gains		Unrealized Losses		Estimated Fair Value
Money market investments (included in cash equivalents)	$	181,528	$	—	$	—	$	181,528
Commercial paper ($58,892 included in cash equivalents)	141,726		1		(51)		141,676
U.S. government agency bonds	25,102		—		(37)		25,065
Corporate debt securities	38,661		4		(16)		38,649
U.S. Treasury bills	26,626		1		(37)		26,590
Total cash equivalents and marketable securities	$	413,643	$	6	$	(141)	$	413,508
Classified as:
Cash and cash equivalents							$	240,420
Marketable securities, short-term							135,412
Marketable securities, long-term							37,676
Total cash equivalents and marketable securities							$	413,508

Schedule of Change in Fair Value of Financial Liability

The following table sets forth a summary of the changes in the fair value of our Level 3 financial liability (in thousands):

	MSKCC Success Payments Liability
Balance at December 31, 2021	$	4,080
Change in fair value	(1,041)
Balance at September 30, 2022	$	3,039

Schedule of Assumptions Used in Valuation of MSKCC Success Payments Liability

	As of September 30, 2022		As of December 31, 2021
Fair value of common stock	$	10.55	$	15.09
Risk-free interest rate	3.83%		1.52%
Expected volatility	81%		75%
Probability of achieving multiple of Initial Share Price	5.7% to 17.9%		7.0% to 20.9%
Expected term (years)	3.9 to 5.3		4.2 to 5.5