Financial Instruments (Details) $ in Thousands	3 Months Ended
Mar. 31, 2023 USD ($) position	Dec. 31, 2022 USD ($)
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	$ 794,300	$ 857,357
Gross Unrealized Gain		1
Gross Unrealized Loss	(11,502)	(16,103)
Estimated Fair Value	782,798	841,255
Other than temporary impairment	$ 0
Number of investments, unrealized loss position \| position	56
Fair value	$ 408,858
Unrealized loss	(11,502)
Gross unrealized loss	11,502	16,103
Amortized Cost
Less than or equal to one year	349,114
Greater than one year but less than five years	71,246
Total	420,360
Fair Value
Less than or equal to one year	341,858
Greater than or equal to one year but less than five years	67,000
Total	408,858
Money market deposits
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	246,954	283,358
Estimated Fair Value	246,954	283,358
Liquid demand deposits
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	126,986	125,596
Estimated Fair Value	126,986	125,596
U.S. Treasury securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	342,958	358,385
Gross Unrealized Loss	(8,554)	(12,328)
Estimated Fair Value	334,404	346,057
Fair value	334,404
Unrealized loss	(8,554)
Gross unrealized loss	8,554	12,328
Corporate bonds and notes
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	19,014	24,045
Gross Unrealized Loss	(295)	(516)
Estimated Fair Value	18,719	23,529
Fair value	18,719
Unrealized loss	(295)
Gross unrealized loss	295	516
Municipal securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	58,388	65,973
Gross Unrealized Gain		1
Gross Unrealized Loss	(2,653)	(3,259)
Estimated Fair Value	55,735	62,715
Fair value	55,735
Unrealized loss	(2,653)
Gross unrealized loss	2,653	3,259
Available-for-sale securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Fair value	0
Cash equivalents
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Estimated Fair Value	373,940	408,954
Short-term investments
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Estimated Fair Value	$ 408,858	$ 432,301

Amount of cash, cash equivalents, restricted cash and investment in marketable securities.

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Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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