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

3 Months Ended

Mar. 31, 2025

Notes Tables

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

	March 31,		December 31,
	2025		2024
Cash	$	377,051	$	679,949
Money market funds		260,303		11,867
U.S. treasuries and government agency bonds		206,946		-
Certificates of deposit		179,117		164,418
Corporate debt securities		3,247		6,712
Auction-rate securities backed by student-loan notes		99		148
Total	$	1,026,763	$	863,094

	March 31,		December 31,
	2025		2024
Reported as:
Cash and cash equivalents	$	637,354	$	691,816
Short-term investments		389,310		171,130
Investment within other long-term assets		99		148
Total	$	1,026,763	$	863,094

Investments Classified by Contractual Maturity Date [Table Text Block]

	Amortized Cost		Fair Value
Due in less than 1 year	$	292,883	$	292,863
Due in 1 - 5 years		96,447		96,447
Due in greater than 5 years		100		99
Total	$	389,430	$	389,409

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

	March 31, 2025
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	$	260,303	$	-	$	-		$	260,303
Certificates of deposit		179,117		-		-			179,117
Corporate debt securities		3,263		-		(16	)		3,247
U.S. treasuries and government agency bonds		206,950		9		(13	)		206,946
Auction-rate securities backed by student-loan notes		100		-		(1	)		99
Total	$	649,733	$	9	$	(30	)	$	649,712

	December 31, 2024
	Amortized Cost		Unrealized Gains		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]

	March 31, 2025
	Less than 12 Months					Greater than 12 Months					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
Corporate debt securities	$	-	$	-		$	3,247	$	(16	)	$	3,247	$	(16	)
U.S. treasuries and government agency bonds		100,408		(13	)		-		-			100,408		(13	)
Auction-rate securities backed by student-loan notes		-		-			99		(1	)		99		(1	)
Total	$	100,408	$	(13	)	$	3,346	$	(17	)	$	103,754	$	(30	)

	December 31, 2024
	Less than 12 Months				Greater than 12 Months					Total
	Fair Value		Unrealized Losses		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]

	March 31,		December 31,
	2025		2024
Cash and cash equivalents	$	637,354	$	691,816
Restricted cash included in other long-term assets		128		125
Total cash, cash equivalents and restricted cash reported on the Condensed Consolidated Statements of Cash Flows	$	637,482	$	691,941