Fair Value Measurements - Schedule of Assets Measured at Fair Value on Recurring Basis (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 0	$ 208,614,000
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, fair value		53,524,000
Financial assets, fair value	217,181,000	262,138,000
Repurchase agreements		53,524,000
Short-term investments		208,614,000
Fair Value, Measurements, Recurring | Money Market Mutual Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, fair value	217,181,000	39,524,000
Repurchase agreements	217,181,000	39,524,000
Fair Value, Measurements, Recurring | Asset-backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments		14,876,000
Fair Value, Measurements, Recurring | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, fair value		41,259,000
Repurchase agreements		41,259,000
Fair Value, Measurements, Recurring | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments		92,508,000
Fair Value, Measurements, Recurring | U.S Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments		59,971,000
Fair Value, Measurements, Recurring | Repurchase Agreements
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, fair value		14,000,000
Repurchase agreements		14,000,000
Fair Value, Measurements, Recurring | Quoted Prices (Unadjusted) in Active Markets for Identical Assets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, fair value		39,524,000
Financial assets, fair value	217,181,000	39,524,000
Repurchase agreements		39,524,000
Fair Value, Measurements, Recurring | Quoted Prices (Unadjusted) in Active Markets for Identical Assets (Level 1) | Money Market Mutual Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, fair value	217,181,000	39,524,000
Repurchase agreements	$ 217,181,000	39,524,000
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, fair value		14,000,000
Financial assets, fair value		222,614,000
Repurchase agreements		14,000,000
Short-term investments		208,614,000
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Asset-backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments		14,876,000
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, fair value		41,259,000
Repurchase agreements		41,259,000
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments		92,508,000
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments		59,971,000
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Repurchase Agreements
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, fair value		14,000,000
Repurchase agreements		$ 14,000,000