Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2023

Fair Value Disclosures [Abstract]

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

The following tables summarize the Company’s Level 1 and Level 2 financial assets measured at fair value on a recurring basis by level within the fair value hierarchy as of June 30, 2023 and December 31, 2022:

		June 30, 2023
	Valuation Hierarchy	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Aggregate Fair Value
		(in thousands)
Assets:
Money market funds(1)	Level 1	$	425,881	$	—	$	—	$	425,881
U.S. government treasuries	Level 2	1,284,324		12		(1,978)		1,282,358
U.S. government agency bonds and discount notes	Level 2	125,880		8		(237)		125,651
Equity securities	Level 1	N/A		N/A		N/A		13,531
Total financial assets		$	1,836,085	$	20	$	(2,215)	$	1,847,421

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(1)Includes $19.9 million of restricted cash equivalents.

		December 31, 2022
	Valuation Hierarchy	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Aggregate Fair Value
		(in thousands)
Assets:
Money market funds(1)	Level 1	$	909,342	$	—	$	—	$	909,342
U.S. government treasuries	Level 2	1,493,841		—		(8,396)		1,485,445
Equity securities	Level 1	N/A		N/A		N/A		31,892
Total financial assets		$	2,403,183	$	—	$	(8,396)	$	2,426,679

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(1)Includes $19.3 million of restricted cash equivalents.

Estimated Fair Value of Significant Unobservable Inputs

As of June 30, 2023, the Company calculated the estimated fair value of the remaining clinical and regulatory milestones related to VIR-3434, an investigational subcutaneously administered HBV-neutralizing monoclonal antibody, or mAb, using the following significant unobservable inputs:

Unobservable input	Range (Weighted-Average)1
Discount rates	13.1% - 14.1% (13.5%)
Probability of achievement	14.4% - 60.0% (42.4%)

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(1)Unobservable inputs were weighted based on the relative fair value of the clinical and regulatory milestone payments.

As of June 30, 2023, the Monte Carlo simulation assumed a commercial product launch and associated discrete revenue forecasts, as well as the following significant unobservable inputs for the remaining commercial milestones related to VIR-3434:

Unobservable input	Value
Volatility	75.0%
Discount rate	11.0%
Probability of achievement	28.7%

Summary of Changes in Estimated Fair Value of Contingent Consideration

The following table sets forth the changes in the estimated fair value of the Company’s contingent consideration obligations (in thousands):

	Contingent Consideration
Balance at December 31, 2022	$	24,937
Changes in fair value	(10)
Balance at June 30, 2023	$	24,927