Note 6. Restricted marketable securities (Tables)

12 Months Ended

Dec. 31, 2025

Debt Securities, Available-for-Sale, Restricted [Abstract]

Schedule of restricted marketable securities

Restricted marketable securities consisted of the following as of December 31, 2025 and 2024 (in thousands):

	2025		2024
U.S. debt	$	115,350	$	109,155
Foreign government obligations	54,156		49,024
Supranational debt	28,276		22,809
U.S. government obligations	19,390		18,148
Total restricted marketable securities	$	217,172	$	199,136

Schedules of restricted marketable securities, including unrealized gains and losses

The following tables summarize the unrealized gains and losses related to our restricted marketable securities, by major security type, as of December 31, 2025 and 2024 (in thousands):

	As of December 31, 2025
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. debt	$	142,790	$	—	$	27,440	$	115,350
Foreign government obligations	67,091		—		12,935		54,156
Supranational debt	30,123		59		1,906		28,276
U.S. government obligations	24,274		—		4,884		19,390
Total	$	264,278	$	59	$	47,165	$	217,172

	As of December 31, 2024
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. debt	$	144,652	$	—	$	35,497	$	109,155
Foreign government obligations	62,595		—		13,571		49,024
Supranational debt	25,351		—		2,542		22,809
U.S. government obligations	24,368		—		6,220		18,148
Total	$	256,966	$	—	$	57,830	$	199,136