Fair Value Measurements - Schedule of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities	$ 195,833	$ 112,553
Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities	61,172	30,054
Certificates of Deposit
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities	39,296	20,046
Municipal Notes
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities	3,061
Repurchase Agreements
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities		15,000
Corporate Notes
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities	81,112	38,783
Government and Agency Notes
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities	11,192	7,574
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities		1,096
Level 1
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities	61,172	30,054
Level 1 | Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities	61,172	30,054
Level 2
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities	134,661	82,499
Level 2 | Certificates of Deposit
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities	39,296	20,046
Level 2 | Municipal Notes
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities	3,061
Level 2 | Repurchase Agreements
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities		15,000
Level 2 | Corporate Notes
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities	81,112	38,783
Level 2 | Government and Agency Notes
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities	$ 11,192	7,574
Level 2 | Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Financial assets and liabilities		$ 1,096