Cash and Cash Equivalents and Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Cash and Cash Equivalents and Fair Value of Financial Instruments	Cash and Cash Equivalents and Fair Value of Financial Instruments Cash and cash equivalents of $548.1 million and $485.9 million as of March 31, 2021 and December 31, 2020, respectively, consisted of bank accounts and highly-liquid U.S. Government money market funds held in sweep accounts with major financial institutions. As of March 31, 2021 and December 31, 2020, cash equivalents were $502.3 million and $447.2 million, respectively, which consisted of money market funds held in sweep accounts. Fair Value Hierarchy The Company measures its financial instruments at fair value. The Company’s cash, cash equivalents, and restricted cash are classified within Level 1 of the fair value hierarchy as they are valued primarily using quoted market prices utilizing market observable inputs. The Company's credit facility is classified within Level 2 as the valuation inputs are based on quoted prices or market observable data of similar instruments. The Company's convertible senior notes are classified within Level 2 as the valuation inputs are based on quoted prices in an inactive market on the last day in the reporting period. As of March 31, 2021, the fair value of the convertible senior notes was $816.8 million, compared to their carrying value of $472.3 million, which is net of unamortized discount and debt issuance costs and excludes amounts classified within additional paid-in capital. Refer to Note 9, Debt and Credit Agreement, for further information regarding the Company’s credit facility and Note 10, Convertible Senior Notes, for further information regarding the Company’s convertible senior notes.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.