Fair Value Measurements

9 Months Ended

Sep. 30, 2024

Fair Value Measurements [Abstract]

Fair Value Measurements

8.  Fair Value Measurements

The following tables present the major security types we held at September 30, 2024 and December 31, 2023 that we regularly measure and carry at fair value. The following tables segregate each security type by the level within the fair value hierarchy of the valuation techniques we utilized to determine the respective security’s fair value (in thousands):

	At September 30, 2024		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)
Cash equivalents (1)	$	255,924	$	255,924	$	—
Corporate debt securities (2)		1,088,978		—		1,088,978
Debt securities issued by U.S. government agencies (3)		228,818		—		228,818
Debt securities issued by the U.S. Treasury (4)		856,333		856,333		—
Debt securities issued by states of the U.S. and political subdivisions of the states (3)		10,668		—		10,668
Publicly traded equity securities included in other current assets (5)		7,699		7,699		—
Total	$	2,448,420	$	1,119,956	$	1,328,464

	At December 31, 2023		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)
Cash equivalents (1)	$	185,424	$	185,424	$	—
Corporate debt securities (6)		801,228		—		801,228
Debt securities issued by U.S. government agencies (3)		334,828		—		334,828
Debt securities issued by the U.S. Treasury (3)		807,679		807,679		—
Debt securities issued by states of the U.S. and political subdivisions of the states (3)		21,155		—		21,155
Publicly traded equity securities included in other current assets (5)		6,301		6,301		—
Total	$	2,156,615	$	999,404	$	1,157,211

The following footnotes reference lines in our condensed consolidated balance sheets:

(1) Included in cash and cash equivalents.

(2) $21.2 million was included in cash and cash equivalents, with the difference included in short-term investments.

(3) Included in short-term investments.

(4) $14.9 million was included in cash and cash equivalents, with the difference included in short-term investments.

(5) Included in other current assets.

(6) $33.0 million was included in cash and cash equivalents, with the difference included in short-term investments.

Convertible Notes

Our 1.75% Notes, 0% Notes and 0.125% Notes had a fair value of $589.8 million, $630.7 million and $44.0 million at September 30, 2024, respectively. Our 1.75% Notes, 0% Notes and 0.125% Notes had a fair value of $661.1 million, $667.8 million and $42.4 million at December 31, 2023, respectively. We determine the fair value of our notes based on quoted market prices for these notes, which are Level 2 measurements because the notes do not trade regularly.