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Fair Value Measurements (Details) - USD ($)
$ in Thousands
Mar. 31, 2024
Dec. 31, 2023
Mar. 31, 2023
Fair Value Measurements [Abstract]      
Available-for-sale securities $ 1,871,515 $ 1,964,890  
Equity securities $ 51,451 $ 49,292  
1.75% Notes [Member]      
Fair Value Measurements [Abstract]      
Interest rate on convertible senior notes 1.75%    
0% Notes [Member]      
Fair Value Measurements [Abstract]      
Interest rate on convertible senior notes 0.00% 0.00% 0.00%
0.125% Notes [Member]      
Fair Value Measurements [Abstract]      
Interest rate on convertible senior notes 0.125% 0.125% 0.125%
Publicly Traded Equity Securities [Member]      
Fair Value Measurements [Abstract]      
Equity securities $ 8,460 $ 6,301  
Recurring Basis [Member]      
Fair Value Measurements [Abstract]      
Cash equivalents [1] 263,639 185,424  
Total 2,143,614 2,156,615  
Recurring Basis [Member] | Corporate Debt Securities [Member]      
Fair Value Measurements [Abstract]      
Available-for-sale securities 775,753 [2] 801,228 [3]  
Recurring Basis [Member] | Corporate Debt Securities [Member] | Cash and Cash Equivalents [Member]      
Fair Value Measurements [Abstract]      
Available-for-sale securities 14,200 33,000  
Recurring Basis [Member] | Debt Securities Issued by U.S. Government Agencies [Member]      
Fair Value Measurements [Abstract]      
Available-for-sale securities [4] 294,346 334,828  
Recurring Basis [Member] | Debt Securities Issued by the U.S. Treasury [Member]      
Fair Value Measurements [Abstract]      
Available-for-sale securities [4] 785,030 807,679  
Recurring Basis [Member] | Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member]      
Fair Value Measurements [Abstract]      
Available-for-sale securities [4] 16,386 21,155  
Recurring Basis [Member] | Publicly Traded Equity Securities [Member] | Other Current Assets [Member]      
Fair Value Measurements [Abstract]      
Equity securities [5] 8,460 6,301  
Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member]      
Fair Value Measurements [Abstract]      
Cash equivalents 263,639 185,424  
Total 1,057,129 999,404  
Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Corporate Debt Securities [Member]      
Fair Value Measurements [Abstract]      
Available-for-sale securities 0 0  
Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Debt Securities Issued by U.S. Government Agencies [Member]      
Fair Value Measurements [Abstract]      
Available-for-sale securities 0 0  
Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Debt Securities Issued by the U.S. Treasury [Member]      
Fair Value Measurements [Abstract]      
Available-for-sale securities 785,030 807,679  
Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member]      
Fair Value Measurements [Abstract]      
Available-for-sale securities 0 0  
Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Publicly Traded Equity Securities [Member]      
Fair Value Measurements [Abstract]      
Equity securities 8,460 6,301  
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member]      
Fair Value Measurements [Abstract]      
Cash equivalents 0 0  
Total 1,086,485 1,157,211  
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | 1.75% Notes [Member]      
Fair Value Measurements [Abstract]      
Convertible notes 601,100 661,100  
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | 0% Notes [Member]      
Fair Value Measurements [Abstract]      
Convertible notes 627,800 667,800  
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | 0.125% Notes [Member]      
Fair Value Measurements [Abstract]      
Convertible notes 42,400 42,400  
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate Debt Securities [Member]      
Fair Value Measurements [Abstract]      
Available-for-sale securities 775,753 801,228  
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Debt Securities Issued by U.S. Government Agencies [Member]      
Fair Value Measurements [Abstract]      
Available-for-sale securities 294,346 334,828  
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Debt Securities Issued by the U.S. Treasury [Member]      
Fair Value Measurements [Abstract]      
Available-for-sale securities 0 0  
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member]      
Fair Value Measurements [Abstract]      
Available-for-sale securities 16,386 21,155  
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Publicly Traded Equity Securities [Member]      
Fair Value Measurements [Abstract]      
Equity securities $ 0 $ 0  
[1] Included in cash and cash equivalents.
[2] $14.2 million was included in cash and cash equivalents, with the difference included in short-term investments.
[3] $33.0 million was included in cash and cash equivalents, with the difference included in short-term investments.
[4] Included in short-term investments.
[5] Included in other current assets.