Fair Value Measurements - Fair Value by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
One Year or Less	$ 104,603	$ 104,711
Over One Year Through Five Years	77,713	93,852
Over Five Years	0	0
Total	182,316	198,563
U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
One Year or Less	37,193	22,550
Over One Year Through Five Years	13,111	30,114
Over Five Years	0	0
Total	50,304	52,664
Yankee bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
One Year or Less	6,073	4,150
Over One Year Through Five Years	2,571	2,010
Over Five Years	0	0
Total	8,644	6,160
Agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
One Year or Less	9,899	14,041
Over One Year Through Five Years	2,377	3,489
Over Five Years	0	0
Total	12,276	17,530
Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
One Year or Less	0	0
Over One Year Through Five Years	12,047	12,229
Over Five Years	0	0
Total	12,047	12,229
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
One Year or Less	8,412	17,690
Over One Year Through Five Years	0	0
Over Five Years	0	0
Total	8,412	17,690
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
One Year or Less	22,095	20,868
Over One Year Through Five Years	7,889	6,667
Over Five Years	0	0
Total	29,984	27,535
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
One Year or Less	20,931	25,412
Over One Year Through Five Years	39,718	39,343
Over Five Years	0	0
Total	$ 60,649	$ 64,755