Note 9 - Cash, Cash Equivalents, Investments and Restricted Cash - Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Continuous Unrealized Loss Position, Less than 12 Months	$ 128,607
Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(24)
Continuous Unrealized Loss Position, 12 Months or Longer	74	$ 6,860
Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1)	(69)
Unrealized Loss Position, Total	128,681	6,860
Unrealized Loss Position, Accumulated Loss, Total	(25)	(69)
US Government Agencies Short-Term Debt Securities [Member]
Continuous Unrealized Loss Position, Less than 12 Months	128,607
Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(24)
Continuous Unrealized Loss Position, 12 Months or Longer	0
Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Unrealized Loss Position, Total	128,607
Unrealized Loss Position, Accumulated Loss, Total	(24)
Corporate Debt Securities [Member]
Continuous Unrealized Loss Position, 12 Months or Longer		6,712
Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(67)
Unrealized Loss Position, Total		6,712
Unrealized Loss Position, Accumulated Loss, Total		(67)
Auction Rate Securities [Member]
Continuous Unrealized Loss Position, Less than 12 Months	0
Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0
Continuous Unrealized Loss Position, 12 Months or Longer	74	148
Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1)	(2)
Unrealized Loss Position, Total	74	148
Unrealized Loss Position, Accumulated Loss, Total	$ (1)	$ (2)