Fair value of financial instruments and marketable securities - Marketable Securities, Unrealized Gains (Losses) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Fair value of financial instruments and marketable securities
Amortized Cost	$ 1,586,915		$ 1,586,915		$ 928,340
Gross Unrealized, Gains	3		3		805
Gross Unrealized, Losses	(3,997)		(3,997)		(18)
Fair Value	1,582,921		1,582,921		929,127
Write downs of available for sale debt securities	0	$ 0	0	$ 0
Increase in allowance for credit losses	0	$ 0	0	$ 0
Commercial paper
Fair value of financial instruments and marketable securities
Amortized Cost	122,351		122,351		93,113
Gross Unrealized, Gains					8
Gross Unrealized, Losses	(206)		(206)		(9)
Fair Value	122,145		122,145		93,112
Corporate debt securities
Fair value of financial instruments and marketable securities
Amortized Cost	679,965		679,965		279,090
Gross Unrealized, Gains					181
Gross Unrealized, Losses	(2,162)		(2,162)		(9)
Fair Value	677,803		677,803		279,262
Government obligations
Fair value of financial instruments and marketable securities
Amortized Cost	784,599		784,599		556,137
Gross Unrealized, Gains	3		3		616
Gross Unrealized, Losses	(1,629)		(1,629)
Fair Value	$ 782,973		$ 782,973		$ 556,753

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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