Fair Value Measurements and Available for Sale Investments - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	$ 531,930	$ 119,465
US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	414,774	87,831
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	2,845	3,766
Agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	59,223	5,814
Commercial and corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	55,088	22,054
Recurring | US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	414,774	87,831
Recurring | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	2,845	3,766
Recurring | Agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	59,223	5,814
Recurring | Commercial and corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	55,088	22,054
Recurring | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	46,030	445,647
Recurring | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	12,610	50,326
Recurring | Quoted Market Prices for Identical Assets (Level 1) | US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	414,774	87,831
Recurring | Quoted Market Prices for Identical Assets (Level 1) | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring | Quoted Market Prices for Identical Assets (Level 1) | Agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring | Quoted Market Prices for Identical Assets (Level 1) | Commercial and corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring | Quoted Market Prices for Identical Assets (Level 1) | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	46,030	445,647
Recurring | Quoted Market Prices for Identical Assets (Level 1) | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	12,610	50,326
Recurring | Significant Other Observable Inputs (Level 2) | US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring | Significant Other Observable Inputs (Level 2) | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	2,845	3,766
Recurring | Significant Other Observable Inputs (Level 2) | Agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	59,223	5,814
Recurring | Significant Other Observable Inputs (Level 2) | Commercial and corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	55,088	22,054
Recurring | Significant Other Observable Inputs (Level 2) | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	0	0
Recurring | Significant Other Observable Inputs (Level 2) | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	0	0
Recurring | Significant Unobservable Inputs (Level 3) | US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Commercial and corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	$ 0	$ 0