Cash, Cash Equivalents and Short-Term Investments - Contractual Maturities (Details) $ in Millions	Mar. 31, 2020 USD ($)
Amortized cost
Due within one year	$ 288.3
Due between one to three years	280.8
Due after three years	25.1
Total	594.2
Estimated fair value
Due within one year	289.1
Due between one to three years	280.1
Due after three years	24.6
Total	$ 593.8

Available For Sale Securities, Debt Maturities After Three Years, Amortized Cost

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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date.

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