Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Summary of Fair Value Assets Measured on Recurring Basis for Cash, Cash Equivalents and Marketable Securities (Details)

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Fair Value Measurements - Summary of Fair Value Assets Measured on Recurring Basis for Cash, Cash Equivalents and Marketable Securities (Details) - USD ($)
$ in Thousands
Sep. 30, 2020
Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash and cash equivalents $ 213,984 $ 198,037
Fair Value Measurements Recurring    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Adjusted cost 220,508 209,086
Gross unrealized gains 1 8
Fair value 220,509 209,094
Cash and cash equivalents 213,984 198,037
Marketable securities 6,525 11,057
Fair Value Measurements Recurring | Cash    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Adjusted cost 46,137 51,560
Fair value 46,137 51,560
Cash and cash equivalents 46,137 51,560
Fair Value Measurements Recurring | Level 1 | Money Market Accounts    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Adjusted cost 167,847 146,477
Fair value 167,847 146,477
Cash and cash equivalents 167,847 146,477
Fair Value Measurements Recurring | Level 2 | Corporate Bonds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Adjusted cost 6,524 2,011
Gross unrealized gains 1 2
Fair value 6,525 2,013
Marketable securities $ 6,525 2,013
Fair Value Measurements Recurring | Level 2 | U.S. Treasury Securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Adjusted cost   9,038
Gross unrealized gains   6
Fair value   9,044
Marketable securities   $ 9,044