Fair Value Measurements (Details) - USD ($) $ in Thousands		Dec. 31, 2024		Dec. 31, 2023		Dec. 31, 2022	Apr. 30, 2021	Dec. 31, 2019
Fair Value Measurements [Abstract]
Available-for-sale securities		$ 2,056,008		$ 1,964,890
Equity securities		$ 46,286		$ 49,292
1.75% Notes [Member]
Fair Value Measurements [Abstract]
Interest rate on convertible senior notes		1.75%		1.75%
0% Notes [Member]
Fair Value Measurements [Abstract]
Interest rate on convertible senior notes		0.00%		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%		0.125%
Publicly Traded Equity Securities [Member]
Fair Value Measurements [Abstract]
Equity securities		$ 5,263		$ 6,301
Recurring Basis [Member]
Fair Value Measurements [Abstract]
Cash equivalents	[1]	180,445		185,424
Total		2,241,716		2,156,615
Recurring Basis [Member] | Corporate Debt Securities [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		1,032,066	[2]	801,228	[3]
Recurring Basis [Member] | Corporate Debt Securities [Member] | Cash and Cash Equivalents [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities				33,000
Recurring Basis [Member] | Debt Securities Issued by U.S. Government Agencies [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities	[2]	208,998		334,828
Recurring Basis [Member] | Debt Securities Issued by the U.S. Treasury [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities	[2]	806,724		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	[2]	7,524		21,155
Recurring Basis [Member] | Other Municipal Debt Securities [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities	[2]	696
Recurring Basis [Member] | Publicly Traded Equity Securities [Member] | Other Current Assets [Member]
Fair Value Measurements [Abstract]
Equity securities	[4]	5,263		6,301
Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value Measurements [Abstract]
Cash equivalents		180,445		185,424
Total		992,432		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		806,724		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] | Other Municipal Debt Securities [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		0
Recurring Basis [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Publicly Traded Equity Securities [Member] | Other Current Assets [Member]
Fair Value Measurements [Abstract]
Equity securities		5,263		6,301
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Abstract]
Cash equivalents		0		0
Total		1,249,284		1,157,211
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | 1.75% Notes [Member]
Fair Value Measurements [Abstract]
Convertible notes		569,300		661,100
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | 0% Notes [Member]
Fair Value Measurements [Abstract]
Convertible notes		612,800		667,800
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | 0.125% Notes [Member]
Fair Value Measurements [Abstract]
Convertible notes				42,400
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate Debt Securities [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		1,032,066		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		208,998		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		7,524		21,155
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Other Municipal Debt Securities [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		696
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Publicly Traded Equity Securities [Member] | Other Current Assets [Member]
Fair Value Measurements [Abstract]
Equity securities		$ 0		$ 0

[1] Included in cash and cash equivalents in our consolidated balance sheets.

[2] Included in short-term investments in our consolidated balance sheets.

[3] $33.0 million was included in cash and cash equivalents, with the difference included in short-term investments in our consolidated balance sheets.

[4] Included in other current assets in our consolidated balance sheets.