Fair Value Measurements - Schedule of Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities	$ 519,629	$ 427,729
Fair Value, Recurring
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Restricted cash	6,116	1,589
Total	568,927	459,760
Fair Value, Recurring \| Money Market Fund
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents	43,182	19,943
Fair Value, Recurring \| Corporate Bonds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents		10,499
Marketable securities, current	192,791	72,923
Marketable securities, non-current	60,652	29,942
Fair Value, Recurring \| US Treasuries
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities, current	169,481	192,275
Marketable securities, non-current	17,172	132,589
Fair Value, Recurring \| US government agencies
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities, current	32,170
Marketable securities, non-current	47,363
Fair Value, Recurring \| Level 1
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Restricted cash	6,116	1,589
Total	315,484	346,396
Fair Value, Recurring \| Level 1 \| Money Market Fund
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents	43,182	19,943
Fair Value, Recurring \| Level 1 \| US Treasuries
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities, current	169,481	192,275
Marketable securities, non-current	17,172	132,589
Fair Value, Recurring \| Level 1 \| US government agencies
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Marketable securities, current	32,170
Marketable securities, non-current	47,363
Fair Value, Recurring \| Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total	253,443	113,364
Fair Value, Recurring \| Level 2 \| Corporate Bonds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents		10,499
Marketable securities, current	192,791	72,923
Marketable securities, non-current	$ 60,652	$ 29,942

Restricted cash fair value.

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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- Definition

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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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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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.

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Amount of investment in marketable security, classified as current.

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Amount of investment in marketable security, classified as noncurrent.

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