Note 5 - Redeemable, Convertible Preferred Stock - Schedule of Redeemable, Convertible Preferred Stock (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Redeemable, convertible preferred stock	$ 222	$ 218
Series B Preferred Stock [Member]
Redeemable, convertible preferred stock	99	98
Series C Preferred Stock [Member]
Redeemable, convertible preferred stock	$ 123	$ 120