The authoritative guidance on fair value measurements establishes a framework with respect to measuring assets and liabilities at fair value on a recurring basis and non-recurring basis. Under the framework, fair value is defined as the exit price, or the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants, as of the measurement date. The framework also establishes a three-tier hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs are inputs market participants would use in valuing the asset or liability and are developed based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the factors market participants would use in valuing the asset or liability and are developed based on the best information available in the circumstances. The hierarchy consists of the following three levels:

The following tables present information about the Company’s financial assets measured at fair value on a recurring basis, based on the three-tier fair value hierarchy:


	June 30, 2026
	Total		Level 1		Level 2		Level 3
	(in thousands)
Equity securities, debt securities and cash equivalents
U.S. government debt securities	$	401,909	$	—	$	401,909	$	—
U.S. agency debt securities		80,954		—		80,954		—
Corporate debt securities		40,887		—		40,887		—
Preferred stock of privately-held companies		15,001		—		—		15,001
Money market accounts		5,108		5,108		—		—
Municipal bonds		1,293		—		1,293		—
Total equity securities, debt securities and cash equivalents	$	545,152	$	5,108	$	525,043	$	15,001


	December 31, 2025
	Total		Level 1		Level 2		Level 3
	(in thousands)
Equity securities, debt securities and cash equivalents
U.S. government debt securities	$	448,233	$	—	$	448,233	$	—
U.S. agency debt securities		157,557		—		157,557		—
Corporate debt securities		47,481		—		47,481		—
Money market accounts		18,398		18,398		—		—
Preferred stock of privately-held companies		15,001		—		—		15,001
Municipal bonds		1,387		—		1,387		—
Yankee debt securities		495		—		495		—
Total equity securities, debt securities and cash equivalents	$	688,552	$	18,398	$	655,153	$	15,001

The Company’s Level 1 assets include money market instruments and are valued based upon observable market prices. Level 2 assets consist of U.S. government and U.S. agency debt securities, municipal bonds, corporate debt securities and Yankee debt securities. Level 2 securities are valued based upon observable inputs that include reported trades, broker/dealer quotes, bids and offers.

As of June 30, 2026, and December 31, 2025, the Company held preferred stock of two privately held companies, which were included in other long-term assets in the accompanying Condensed Consolidated Balance Sheets, that were measured using unobservable (Level 3) inputs. For the value of the investment in private equity securities, the Company elected to measure such investments at cost minus impairment, as the preferred stock of the privately held companies did not have a readily determinable fair value.

An impairment of $9.9 million was recognized in 2025 related to Helio Genomics, Inc. There was no impairment loss recorded as of June 30, 2026, for the other preferred stock investment.

There were no transfers between fair value measurement levels during the three and six months ended June 30, 2026, and 2025.