Financial Instruments - Amortized Cost and Estimated Fair Value of Marketable Securities, by Contractual Maturity (Details) $ in Thousands	Jun. 30, 2020 USD ($)
Amortized Cost
Due in one year or less	$ 950,151
Due after one year through five years	350,706
Amortized Cost	1,300,857
Estimated Fair Value
Due in one year or less	955,384
Due after one year through five years	354,916
Total	$ 1,310,300

Amortized cost of 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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