Fair Value Measurements (Details) - USD ($) $ in Thousands		Sep. 30, 2024		Dec. 31, 2023		Sep. 30, 2023
Fair Value Measurements [Abstract]
Available-for-sale securities		$ 2,184,797		$ 1,964,890
Equity securities		$ 48,722		$ 49,292
1.75% Notes [Member]
Fair Value Measurements [Abstract]
Interest rate on convertible senior notes		1.75%		1.75%		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		$ 7,699		$ 6,301
Recurring Basis [Member]
Fair Value Measurements [Abstract]
Cash equivalents	[1]	255,924		185,424
Total		2,448,420		2,156,615
Recurring Basis [Member] | Corporate Debt Securities [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		1,088,978	[2]	801,228	[3]
Recurring Basis [Member] | Corporate Debt Securities [Member] | Cash and Cash Equivalents [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		21,200		33,000
Recurring Basis [Member] | Debt Securities Issued by U.S. Government Agencies [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities	[4]	228,818		334,828
Recurring Basis [Member] | Debt Securities Issued by the U.S. Treasury [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		856,333	[5]	807,679	[4]
Recurring Basis [Member] | Debt Securities Issued by the U.S. Treasury [Member] | Cash and Cash Equivalents [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		14,900
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]	10,668		21,155
Recurring Basis [Member] | Publicly Traded Equity Securities [Member] | Other Current Assets [Member]
Fair Value Measurements [Abstract]
Equity securities	[6]	7,699		6,301
Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value Measurements [Abstract]
Cash equivalents		255,924		185,424
Total		1,119,956		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		856,333		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		7,699		6,301
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Abstract]
Cash equivalents		0		0
Total		1,328,464		1,157,211
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | 1.75% Notes [Member]
Fair Value Measurements [Abstract]
Convertible notes		589,800		661,100
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | 0% Notes [Member]
Fair Value Measurements [Abstract]
Convertible notes		630,700		667,800
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | 0.125% Notes [Member]
Fair Value Measurements [Abstract]
Convertible notes		44,000		42,400
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate Debt Securities [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		1,088,978		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		228,818		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		10,668		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] $21.2 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] $14.9 million was included in cash and cash equivalents, with the difference included in short-term investments.

[6] Included in other current assets.