Investments - Schedule of Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Available-for-sale securities:
Amortized Cost	$ 481,423
Estimated Fair Value	474,320
Held-to-maturity securities:
Estimated Fair Value	1,820
Long-term Investments
Amortized Cost	235,720	$ 230,811
Gross Unrealized Losses, Less than One Year	(5,706)	(1,381)
Gross Unrealized Losses, Greater than One Year	(189)
Total long-term investments	229,825	229,430
Total investments
Amortized Cost	483,243	429,407
Gross Unrealized Gains	37	287
Gross Unrealized Losses, Less than One Year	(6,951)	(1,497)
Gross Unrealized Losses, Greater than One Year	(189)
Estimated Fair Value	476,140	428,197
Short-term investments
Available-for-sale securities:
Amortized Cost	247,523	198,596
Gross Unrealized Gains	37	287
Gross Unrealized Losses, Less than One Year	(1,245)	(116)
Estimated Fair Value	246,315	198,767
Short-term investments | Corporate debt securities
Available-for-sale securities:
Amortized Cost	96,729	85,201
Gross Unrealized Gains	16	177
Gross Unrealized Losses, Less than One Year	(483)	(39)
Estimated Fair Value	96,262	85,339
Short-term investments | U.S. government and agency debt securities
Available-for-sale securities:
Amortized Cost	83,261	45,349
Gross Unrealized Gains	7	35
Gross Unrealized Losses, Less than One Year	(356)	(24)
Estimated Fair Value	82,912	45,360
Short-term investments | Non-U.S. government debt securities
Available-for-sale securities:
Amortized Cost	67,533	68,046
Gross Unrealized Gains	14	75
Gross Unrealized Losses, Less than One Year	(406)	(53)
Estimated Fair Value	67,141	68,068
Long-term investments
Available-for-sale securities:
Amortized Cost	233,900	228,991
Gross Unrealized Losses, Less than One Year	(5,706)	(1,381)
Gross Unrealized Losses, Greater than One Year	(189)
Estimated Fair Value	228,005	227,610
Long-term investments | Certificates of deposit
Held-to-maturity securities:
Amortized Cost	1,820	1,820
Estimated Fair Value	1,820	1,820
Long-term investments | Corporate debt securities
Available-for-sale securities:
Amortized Cost	132,275	111,793
Gross Unrealized Losses, Less than One Year	(3,055)	(654)
Estimated Fair Value	129,220	111,139
Long-term investments | U.S. government and agency debt securities
Available-for-sale securities:
Amortized Cost	79,824	81,296
Gross Unrealized Losses, Less than One Year	(2,237)	(517)
Estimated Fair Value	77,587	80,779
Long-term investments | Non-U.S. government debt securities
Available-for-sale securities:
Amortized Cost	21,801	35,902
Gross Unrealized Losses, Less than One Year	(414)	(210)
Gross Unrealized Losses, Greater than One Year	(189)
Estimated Fair Value	$ 21,198	$ 35,692