Note 4 - Investments (Tables)

3 Months Ended

Mar. 31, 2023

Notes Tables

Debt Securities, Available-for-Sale [Table Text Block]

	March 31, 2023
	Amortized		Gross unrealized				Estimated
(In thousands)	Cost		Gains		Losses		Fair Value
Available-for-sale securities, current portion
U.S. government securities	$	9,386	$	-	$	9	$	9,377
Corporate debt securities		24,663		7		7		24,663
Other debt securities		1,743		-		3		1,740
Total short-term		35,792		7		19		35,780
Available-for-sale securities, long-term
Other debt securities		2,018		2		1		2,019
Total marketable securities	$	37,810	$	9	$	20	$	37,799

	Amortized		Estimated
(In thousands)	Cost		Fair Value
Due in one year or less	$	35,792	$	35,780
Due after one year through five years		2,018		2,019
Total	$	37,810	$	37,799