Fair Value Measurements - Summary of Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 195,320	$ 112,493
Unrealized Gains	547	65
Unrealized Losses	(34)	(5)
Financial assets and liabilities	195,833	112,553
Cash equivalents (maturities within 90 days)	62,152	47,140
Short-term investments (maturities within one year)	73,548	48,650
Long-term investments (maturities beyond 1 year)	60,133	16,763
Total cash equivalents and investments	195,833	112,553
Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	61,172	30,054
Financial assets and liabilities	61,172	30,054
Certificates of Deposit
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	39,046	19,992
Unrealized Gains	250	54
Financial assets and liabilities	39,296	20,046
Municipal Notes
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	3,060
Unrealized Gains	1
Financial assets and liabilities	3,061
Repurchase Agreements
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		15,000
Financial assets and liabilities		15,000
Corporate Notes
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	80,871	38,788
Unrealized Gains	274
Unrealized Losses	(33)	(5)
Financial assets and liabilities	81,112	38,783
Government Notes
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	11,171	7,563
Unrealized Gains	22	11
Unrealized Losses	(1)
Financial assets and liabilities	$ 11,192	7,574
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		1,096
Financial assets and liabilities		$ 1,096

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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Amortized cost 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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