Fair Value Measurements Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	$ 546,717	$ 579,105
US Government Securities, at Carrying Value	23,929	5,782
Municipal bonds	10,564	26,009
Total	581,210	610,896
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	23,991	5,783
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	62	1
Debt Securities, Available-for-sale	23,929	5,782
Municipal Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	10,596	26,017
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	32	8
Debt Securities, Available-for-sale	10,564	26,009
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	546,717	579,105
US Government Securities, at Carrying Value	23,929	5,782
Municipal bonds	0	0
Total	570,646	584,887
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	0	0
US Government Securities, at Carrying Value	0	0
Municipal bonds	10,564	26,009
Total	$ 10,564	$ 26,009