Note 11 - Fair Value Measurements - Summary of Fair Value Measurements by Level (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Restricted cash and cash equivalents	$ 30,267		$ 19,947
Available-for-sale securities (USD)	123,911	$ 127,727
Total financial assets	426,740
Corporate Debt Securities [Member]
Available-for-sale securities (USD)	0	2,441
Fair Value, Inputs, Level 1 [Member]
Total financial assets	386,975
Fair Value, Inputs, Level 2 [Member]
Total financial assets	39,305
Fair Value, Inputs, Level 3 [Member]
Total financial assets	460
Fair Value, Recurring [Member]
Cash and cash equivalents	84,807	107,076
Restricted cash and cash equivalents	30,267	18,892
Total financial assets		391,591
Fair Value, Recurring [Member] \| Equity Securities [Member]
Marketable equity securities	187,755	137,896
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member]
Available-for-sale securities (USD)	58,812	60,171
Fair Value, Recurring [Member] \| Asset-Backed Securities [Member]
Available-for-sale securities (USD)	16,646	17,659
Fair Value, Recurring [Member] \| US Treasury Securities [Member]
Available-for-sale securities (USD)	44,671	45,850
Fair Value, Recurring [Member] \| US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities (USD)	3,782	4,047
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	84,807	107,076
Restricted cash and cash equivalents	30,267	18,892
Total financial assets		352,574
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Equity Securities [Member]
Marketable equity securities	187,755	137,896
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Corporate Debt Securities [Member]
Available-for-sale securities (USD)	39,475	42,860
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Asset-Backed Securities [Member]
Available-for-sale securities (USD)	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| US Treasury Securities [Member]
Available-for-sale securities (USD)	44,671	45,850
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities (USD)	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Total financial assets		38,568
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Equity Securities [Member]
Marketable equity securities	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Corporate Debt Securities [Member]
Available-for-sale securities (USD)	19,337	17,311
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Asset-Backed Securities [Member]
Available-for-sale securities (USD)	16,186	17,210
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| US Treasury Securities [Member]
Available-for-sale securities (USD)	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities (USD)	3,782	4,047
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Total financial assets		449
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Equity Securities [Member]
Marketable equity securities	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Corporate Debt Securities [Member]
Available-for-sale securities (USD)	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Asset-Backed Securities [Member]
Available-for-sale securities (USD)	460	449
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| US Treasury Securities [Member]
Available-for-sale securities (USD)	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities (USD)	$ 0	$ 0

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