Fair Value Measurements - Schedule of Available for sale Investments by Security Type (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Investments, Amortized Cost	$ 266,465
Available-for-sale Investments, Gross Unrealized Gains	295
Available-for-sale Investments, Gross Unrealized Losses	(20)
Available-for-sale Investments, Total Fair Value	266,740
U S Treasury and Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Investments, Amortized Cost	77,993
Available-for-sale Investments, Gross Unrealized Gains	57
Available-for-sale Investments, Total Fair Value	78,050
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Investments, Amortized Cost	32,413
Available-for-sale Investments, Total Fair Value	32,413
Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Investments, Amortized Cost	156,059
Available-for-sale Investments, Gross Unrealized Gains	238
Available-for-sale Investments, Gross Unrealized Losses	(20)
Available-for-sale Investments, Total Fair Value	$ 156,277

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

+ References

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Amount 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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-Publisher FASB
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