Note 7 - Marketable Securities - Short-term and Long-term Available for Sale Securities (Details) $ in Thousands	Sep. 30, 2021 USD ($)
Amortized Cost	$ 36,027
Unrealized Gains	100
Unrealized Losses	(28)
Fair Value	36,099
Bank Time Deposits [Member]
Amortized Cost	4,160
Unrealized Gains	38
Unrealized Losses	0
Fair Value	4,198
US States and Political Subdivisions Debt Securities [Member]
Amortized Cost	18,515
Unrealized Gains	28
Unrealized Losses	(13)
Fair Value	18,530
Corporate Debt Securities [Member]
Amortized Cost	11,852
Unrealized Gains	34
Unrealized Losses	(14)
Fair Value	11,872
US Government Agencies Debt Securities [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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Amount, before tax, of unrealized loss 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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