Note 5 - Investments, Available-for-sale (Tables)

12 Months Ended

Dec. 31, 2022

Notes Tables

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

	December 31, 2022
	(in thousands)
	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value		Short-term investments		Long-term investments
Commercial Paper	$	12,364	$	-	$	(49	)	$	12,315	$	12,315	$	-
Corporate Bonds		55,201		-		(447	)		54,754		50,889		3,865
U.S. Government Agencies		999		-		(8	)		991		991		-
Total Investments	$	68,564	$	-	$	(504	)	$	68,060	$	64,195	$	3,865

	December 31, 2021
	(in thousands)
	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value		Short-term investments		Long-term investments
Commercial Paper	$	50,705	$	-	$	(46	)	$	50,659	$	50,660	$	-
Corporate Bonds		67,239		1		(202	)		67,038		29,602		37,435
Total Investments	$	117,944	$	1	$	(248	)	$	117,697	$	80,262	$	37,435

Investments Classified by Contractual Maturity Date [Table Text Block]

	December 31, 2022
	(in thousands)
	Amortized Cost		Fair Value
Mature in less than one year	$	64,662	$	64,195
Mature in one to two years		3,902		3,865
Total	$	68,564	$	68,060