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Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	$ 104,246	$ 162,942
Fair Value, Measurements, Recurring
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	104,246	162,942
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	45,839	83,092
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	58,407	79,850
Fair Value, Measurements, Recurring | US Government
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	42,551	66,094
Fair Value, Measurements, Recurring | US Government | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	42,551	66,094
Fair Value, Measurements, Recurring | Corporate Bonds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	37,080	68,084
Fair Value, Measurements, Recurring | Corporate Bonds | Significant Other Observable Inputs (Level 2)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	37,080	68,084
Fair Value, Measurements, Recurring | Commercial Paper
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	19,696	7,658
Fair Value, Measurements, Recurring | Commercial Paper | Significant Other Observable Inputs (Level 2)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	19,696	7,658
Fair Value, Measurements, Recurring | Money Market Funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	3,288	16,998
Fair Value, Measurements, Recurring | Money Market Funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	3,288	16,998
Fair Value, Measurements, Recurring | Certificates of Deposit
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	1,631	4,108
Fair Value, Measurements, Recurring | Certificates of Deposit | Significant Other Observable Inputs (Level 2)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities:	$ 1,631	$ 4,108

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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).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
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-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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