Note 4 - Investments - Available-For-Sale Marketable Securities (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale, Amortized Cost, Current	$ 35,792
Debt Securities, Available-for-Sale, Unrealized Gain, Current	7
Debt Securities, Available-for-Sale, Unrealized Loss, Current	19
Available-for-sale securities, current portion	35,780	$ 43,260
Debt Securities, Available-for-Sale, Amortized Cost, NoncurrentDebt Securities, Available-for-Sale, Amortized Cost, Noncurrent	2,018
Available-for-sale securities, long-term	2,019	1,332
Debt Securities, Available-for-Sale, Amortized Cost, Total	37,810
Debt Securities, Available-for-Sale, Unrealized Gain	9
Debt Securities, Available-for-Sale, Unrealized Loss	20
Debt Securities, Available-for-Sale, Total	37,799
Due in one year or less, amortized cost	35,792
Due in one year or less, fair value	35,780	$ 43,260
Due after one year through five years, amortized cost	2,018
Due after one year through five years, fair value	2,019
Total, amortized cost	37,810
Marketable debt securities	37,799
US Government Agencies Debt Securities [Member]
Debt Securities, Available-for-Sale, Amortized Cost, Current	9,386
Debt Securities, Available-for-Sale, Unrealized Gain, Current	0
Debt Securities, Available-for-Sale, Unrealized Loss, Current	9
Available-for-sale securities, current portion	9,377
Due in one year or less, amortized cost	9,386
Due in one year or less, fair value	9,377
Corporate Debt Securities [Member]
Debt Securities, Available-for-Sale, Amortized Cost, Current	24,663
Debt Securities, Available-for-Sale, Unrealized Gain, Current	7
Debt Securities, Available-for-Sale, Unrealized Loss, Current	7
Available-for-sale securities, current portion	24,663
Due in one year or less, amortized cost	24,663
Due in one year or less, fair value	24,663
Other Debt Obligations [Member]
Debt Securities, Available-for-Sale, Amortized Cost, Current	1,743
Debt Securities, Available-for-Sale, Unrealized Gain, Current	0
Debt Securities, Available-for-Sale, Unrealized Loss, Current	3
Available-for-sale securities, current portion	1,740
Debt Securities, Available-for-Sale, Amortized Cost, NoncurrentDebt Securities, Available-for-Sale, Amortized Cost, Noncurrent	2,018
Debt Securities, Available-for-Sale, Unrealized Gain, Noncurrent	2
Debt Securities, Available-for-Sale, Unrealized Loss, Noncurrent	1
Available-for-sale securities, long-term	2,019
Due in one year or less, amortized cost	1,743
Due in one year or less, fair value	1,740
Due after one year through five years, amortized cost	$ 2,018

The unrealized gain of debt securities available-for-sale classified as current.

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The amount of unrealized gain of debt securities available-for-sale classified as noncurrent.

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Current portion of amount of unrealized loss 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 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).

+ References

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Amortized cost of 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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