Investments - Continuous Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses	$ (4,559)	$ (922)
Fair Value	546,000	372,482
U.S. treasury securities
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses	(2,685)	(474)
Fair Value	228,993	146,454
U.S. agency and government sponsored securities
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses	(89)	(25)
Fair Value	4,907	4,970
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses	(126)	(4)
Fair Value	114,980	30,285
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses	(1,348)	(345)
Fair Value	156,246	145,522
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses	(311)	(74)
Fair Value	$ 40,874	$ 45,251