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Fair Value Measurements - Schedule of Fair Value and Amortized Cost of Investments in Marketable Securities by Major Security Type (Details) - USD ($) $ in Thousands | Dec. 31, 2019 | Dec. 31, 2018
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Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |
Amortized Cost | $ 188,206 | $ 259,833
Unrealized Gain | 67 |
Unrealized Loss | (3) | (108)
Fair Value | 188,270 | 259,725
Money Market Funds |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |
Amortized Cost | 45,498 | 45,017
Fair Value | 45,498 | 45,017
U.S. Government Agency Obligations |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |
Amortized Cost | 74,801 | 103,957
Unrealized Gain | 12 |
Unrealized Loss | (1) | (17)
Fair Value | 74,812 | 103,940
Corporate Securities and Commercial Paper |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |
Amortized Cost | 67,907 | 110,859
Unrealized Gain | 55 |
Unrealized Loss | (2) | (91)
Fair Value | $ 67,960 | $ 110,768

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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References No definition available. + Details
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- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 + Details
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- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References No definition available. + Details
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- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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