Note 5 - Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2022

Notes Tables

Marketable Securities [Table Text Block]

	December 31, 2022
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Marketable securities
Corporate and municipal debt securities	$	4,950	$	26	$	(3	)	$	4,973

Investments Classified by Contractual Maturity Date [Table Text Block]

	December 31, 2022				December 31, 2021
(in thousands)	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due within one year	$	1,594	$	1,602	$	−	$	−
Due after one year through three years		3,356		3,371		−		−
Total	$	4,950	$	4,973	$	−	$	−