Note 4 - Investments - Available-For-Sale Marketable Securities (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-Sale, Amortized Cost, Current	$ 43,313
Debt Securities, Available-for-Sale, Unrealized Gain, Current	7
Debt Securities, Available-for-Sale, Unrealized Loss, Current	60
Available-for-sale securities, current portion	43,260	$ 0
Debt Securities, Available-for-Sale, Amortized Cost, NoncurrentDebt Securities, Available-for-Sale, Amortized Cost, Noncurrent	1,329
Available-for-sale securities, long term	1,332	0
Debt Securities, Available-for-Sale, Amortized Cost, Total	44,642
Debt Securities, Available-for-Sale, Unrealized Gain	10
Debt Securities, Available-for-Sale, Unrealized Loss	60
Debt Securities, Available-for-Sale, Total	44,592
Due in one year or less	43,313
Due in one year or less	43,260	$ 0
Due after one year through five years	1,329
Due after one year through five years	1,332
Total	44,642
Marketable debt securities	44,592
US Government Agencies Debt Securities [Member]
Debt Securities, Available-for-Sale, Amortized Cost, Current	15,087
Debt Securities, Available-for-Sale, Unrealized Gain, Current	1
Debt Securities, Available-for-Sale, Unrealized Loss, Current	37
Available-for-sale securities, current portion	15,051
Due in one year or less	15,087
Due in one year or less	15,051
Corporate Debt Securities [Member]
Debt Securities, Available-for-Sale, Amortized Cost, Current	26,057
Debt Securities, Available-for-Sale, Unrealized Gain, Current	6
Debt Securities, Available-for-Sale, Unrealized Loss, Current	16
Available-for-sale securities, current portion	26,047
Due in one year or less	26,057
Due in one year or less	26,047
Other Debt Obligations [Member]
Debt Securities, Available-for-Sale, Amortized Cost, Current	2,169
Debt Securities, Available-for-Sale, Unrealized Gain, Current	0
Debt Securities, Available-for-Sale, Unrealized Loss, Current	7
Available-for-sale securities, current portion	2,162
Debt Securities, Available-for-Sale, Amortized Cost, NoncurrentDebt Securities, Available-for-Sale, Amortized Cost, Noncurrent	1,329
Debt Securities, Available-for-Sale, Unrealized Gain, Noncurrent	3
Debt Securities, Available-for-Sale, Unrealized Loss, Noncurrent	0
Available-for-sale securities, long term	1,332
Due in one year or less	2,169
Due in one year or less	2,162
Due after one year through five years	$ 1,329

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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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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