Note 8 - Marketable Securities - Short-term and Long-term Available for Sale Securities (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Amortized Cost	$ 56,062
Unrealized Gains	0
Unrealized Losses	(1,552)
Fair Value	54,510
US States and Political Subdivisions Debt Securities [Member]
Amortized Cost	17,991
Unrealized Gains	0
Unrealized Losses	(494)
Fair Value	17,497
Corporate Debt Securities [Member]
Amortized Cost	9,602
Unrealized Gains	0
Unrealized Losses	(259)
Fair Value	9,343
US Government Agencies Debt Securities [Member]
Amortized Cost	25,780
Unrealized Gains	0
Unrealized Losses	(787)
Fair Value	24,993
Bank Time Deposits [Member]
Amortized Cost	1,189
Unrealized Gains	0
Unrealized Losses	(11)
Fair Value	1,178
Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Amortized Cost	1,500
Unrealized Gains	0
Unrealized Losses	(1)
Fair Value	$ 1,499

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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