Financial Instruments (Details) $ in Thousands	Sep. 30, 2023 USD ($) position	Dec. 31, 2022 USD ($)
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	$ 941,687	$ 914,494
Gross Unrealized Gain		1
Gross Unrealized Loss	(5,130)	(16,103)
Estimated Fair Value	$ 936,557	898,392
Number of investments, unrealized loss position | position	38
Fair value	$ 267,847
Unrealized loss	(5,130)
Gross unrealized loss	5,130	16,103
Amortized Cost
Less than or equal to one year	242,845
Greater than one year but less than five years	30,132
Total	272,977
Fair Value
Less than or equal to one year	239,773
Greater than or equal to one year but less than five years	28,074
Total	267,847
Cash, cash equivalents, and restricted cash
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	668,710	466,091
Estimated Fair Value	668,710	466,091
U.S. Treasury securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	227,276	358,385
Gross Unrealized Loss	(2,833)	(12,328)
Estimated Fair Value	224,443	346,057
Fair value	224,443
Unrealized loss	(2,833)
Gross unrealized loss	2,833	12,328
Corporate bonds and notes
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	4,000	24,045
Gross Unrealized Loss	(24)	(516)
Estimated Fair Value	3,976	23,529
Fair value	3,976
Unrealized loss	(24)
Gross unrealized loss	24	516
Municipal securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	41,701	65,973
Gross Unrealized Gain		1
Gross Unrealized Loss	(2,273)	(3,259)
Estimated Fair Value	39,428	62,715
Fair value	39,428
Unrealized loss	(2,273)
Gross unrealized loss	2,273	3,259
Available-for-sale securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Fair value	0
Cash, cash equivalents, and restricted cash
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Estimated Fair Value	668,710	466,091
Short-term investments
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Estimated Fair Value	$ 267,847	$ 432,301