Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2021

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Summary of Financial Instruments Measured at Fair Value on a Recurring Basis

The following tables set forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy as of March 31, 2021 and December 31, 2020:

	March 31, 2021
(in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents (money market funds)	$	306,446	$	—	$	—	$	306,446
Totals	$	306,446	$	—	$	—	$	306,446
	December 31, 2020
(in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents (money market funds)	$	314,636	$	—	$	—	$	314,636
Totals	$	314,636	$	—	$	—	$	314,636

Level 3

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Summary of Fair Value of Series B Preferred Stock Tranche Rights Liability

The fair value of the Series B Preferred Stock tranche rights liability was estimated using a probability-weighted present value of the benefit of investment with the following significant unobservable inputs (Level 3):

	Valuation Dates
	March 23, 2020 (Tranche 3 settlement)
Implied equity value (in millions)	$	208.2
Probability of success of reaching necessary    milestone:
Tranche 2 milestone	N/A
Tranche 3 milestone (by March 31, 2020)		90	%
Expected industry return over period during which    milestones are expected to be achieved		13.0	%
Risk-free interest rate		1.1	%

Summary of Changes in Level 3 Liabilities Measures at Fair Value on a Recurring Basis

The following table presents changes during the three months ended March 31, 2021 and 2020 in Level 3 liabilities measured at fair value on a recurring basis:

(in thousands)	Preferred Stock Tranche Rights Liability
Balances at January 1, 2020	$	5,400
Change in estimated fair value		(1,265	)
Settlement of tranche right		(4,135	)
Balances at March 31, 2020	$	—