Note 9 - Cash, Cash Equivalents, Investments and Restricted Cash (Tables)

6 Months Ended

Jun. 30, 2025

Notes Tables

Fair Value, by Balance Sheet Grouping [Table Text Block]

	June 30,		December 31,
	2025		2024
Cash	$	414,800	$	679,949
Money market funds		372,582		11,867
U.S. treasuries and government agency bonds		177,311		-
Certificates of deposit		181,384		164,418
Corporate debt securities		-		6,712
Auction-rate securities backed by student-loan notes		74		148
Total	$	1,146,151	$	863,094

	June 30,		December 31,
	2025		2024
Reported as:
Cash and cash equivalents	$	787,382	$	691,816
Short-term investments		358,695		171,130
Investment within other long-term assets		74		148
Total	$	1,146,151	$	863,094

Investments Classified by Contractual Maturity Date [Table Text Block]

	Amortized Cost		Fair Value
Due in less than 1 year	$	261,048	$	261,027
Due in 1 - 5 years		97,668		97,668
Due in greater than 5 years		75		74
Total	$	358,791	$	358,769

Unrealized Gain (Loss) on Investments [Table Text Block]

	June 30, 2025
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	$	372,582	$	-	$	-		$	372,582
Certificates of deposit		181,384		-		-			181,384
U.S. treasuries and government agency bonds		177,332		3		(24	)		177,311
Auction-rate securities backed by student-loan notes		75		-		(1	)		74
Total	$	731,373	$	3	$	(25	)	$	731,351

	December 31, 2024
	Amortized Cost		Unrealized Losses			Fair Value
Money market funds	$	11,867	$	-		$	11,867
Certificates of deposit		164,418		-			164,418
Corporate debt securities		6,779		(67	)		6,712
Auction-rate securities backed by student-loan notes		150		(2	)		148
Total	$	183,214	$	(69	)	$	183,145

Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block]

	June 30, 2025
	Less than 12 Months					Greater than 12 Months					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. treasuries and government agency bonds	$	128,607	$	(24	)	$	-	$	-		$	128,607	$	(24	)
Auction-rate securities backed by student-loan notes		-		-			74		(1	)		74		(1	)
Total	$	128,607	$	(24	)	$	74	$	(1	)	$	128,681	$	(25	)

	December 31, 2024
	Greater than 12 Months					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
Corporate debt securities	$	6,712	$	(67	)	$	6,712	$	(67	)
Auction-rate securities backed by student-loan notes		148		(2	)		148		(2	)
Total	$	6,860	$	(69	)	$	6,860	$	(69	)

Restrictions on Cash and Cash Equivalents [Table Text Block]

	June 30,		December 31,
	2025		2024
Cash and cash equivalents	$	787,382	$	691,816
Restricted cash included in other long-term assets		142		125
Total cash, cash equivalents and restricted cash reported on the Condensed Consolidated Statements of Cash Flows	$	787,524	$	691,941