Fair Value Measurements - Narrative (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted cash	$ 4,223,000	$ 6,660,000
Amortized cost of available-for-sale investments with maturities less than one year	966,300,000	866,500,000
Amortized cost of available-for-sale investments with maturities greater than one year	544,400,000	56,500,000
Net unrealized gains (losses) on investments, net of tax	2,700,000	200,000
Standby Letters of Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted cash	6,700,000	6,700,000
Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	613,800,000
Convertible Debt \| 2026 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	1,397,300,000
Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unrealized gain	0	0
Unrealized loss	$ 0	$ 0

Cash And Cash Equivalents, Accumulated Gross Unrealized Gain, Before Tax

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Cash And Cash Equivalents, Accumulated Gross Unrealized Loss, Before Tax

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Debt Securities, Available-For-Sale, Maturity, Allocated And Single Maturity Date, After One Year, Amortized Cost

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Amount, after tax, of accumulated unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of cash restricted as to withdrawal or usage, classified as noncurrent. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits.

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