Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2022

Fair Value Measurements [Abstract]

Assets Measured at Fair Value on a Recurring Basis

The following tables present the major security types we held at September 30, 2022 and December 31, 2021 that we regularly measure and carry at fair value. As of December 31, 2021, one of our investments in publicly held biotechnology companies was subject to trading restrictions that ended in the third quarter of 2022; as a result, we included a lack of marketability discount in valuing this investment, which is a Level 3 input. 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 securities’ fair value (in thousands):

	At September 30, 2022		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash equivalents (1)	$	231,960	$	231,960	$	—	$	—
Corporate debt securities (2)		728,054		—		728,054		—
Debt securities issued by U.S. government agencies (2)		130,767		—		130,767		—
Debt securities issued by the U.S. Treasury (3)		750,933		750,933		—		—
Debt securities issued by states of the U.S. and political subdivisions of the states (4)		85,315		—		85,315		—
Other municipal debt securities (3)		5,964		—		5,964		—
Publicly traded equity securities included in other current assets		7,256		7,256		—		—
Total	$	1,940,249	$	990,149	$	950,100	$	—

	At December 31, 2021		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash equivalents (1)	$	541,199	$	541,199	$	—	$	—
Corporate debt securities (3)		764,059		—		764,059		—
Debt securities issued by U.S. government agencies (3)		120,868		—		120,868		—
Debt securities issued by the U.S. Treasury (3)		182,634		182,634		—		—
Debt securities issued by states of the U.S. and political subdivisions of the states (5)		174,464		—		174,464		—
Other municipal debt securities (3)		6,099		—		6,099		—
Publicly traded equity securities included in other current assets		18,205		3,875		—		14,330
Total	$	1,807,528	$	727,708	$	1,065,490	$	14,330

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

(1) Included in cash and cash equivalents in our condensed consolidated balance sheet.

(2) $23.5 million was included in cash and cash equivalents in our condensed consolidated balance sheet, with the difference included in short-term investments in our condensed consolidated balance sheet.

(3) Included in short-term investments.

(4) $10.0 million was included in cash and cash equivalents in our condensed consolidated balance sheet, with the difference included in short-term investments in our condensed consolidated balance sheet.

(5) $2.3 million was included in cash and cash equivalents in our condensed consolidated balance sheet, with the difference included in short-term investments in our condensed consolidated balance sheet.