Note 10 - Fair Value Measurements - Summary of Fair Value Measurements by Level (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024	Jun. 30, 2024
Restricted cash and cash equivalents	$ 19,370		$ 29,391
Available-for-sale securities	133,701	$ 119,804
Corporate Debt Securities [Member]
Available-for-sale securities	60,888	57,471
Fair Value, Recurring [Member]
Cash and cash equivalents	110,992	76,121
Restricted cash and cash equivalents	19,370	20,801
Total financial assets	426,968	379,980
Fair Value, Recurring [Member] \| Equity Securities [Member]
Marketable equity securities	162,905	163,254
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member]
Available-for-sale securities	60,888	57,471
Fair Value, Recurring [Member] \| Asset-Backed Securities [Member]
Available-for-sale securities	13,381	14,410
Fair Value, Recurring [Member] \| US Treasury Securities [Member]
Available-for-sale securities	55,718	44,186
Fair Value, Recurring [Member] \| US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities	3,714	3,737
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	110,992	76,121
Restricted cash and cash equivalents	19,370	20,801
Total financial assets	386,937	348,824
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Equity Securities [Member]
Marketable equity securities	162,905	163,254
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Corporate Debt Securities [Member]
Available-for-sale securities	37,152	43,656
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Asset-Backed Securities [Member]
Available-for-sale securities	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| US Treasury Securities [Member]
Available-for-sale securities	55,718	44,186
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities	800	806
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	40,031	31,156
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	23,736	13,815
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Asset-Backed Securities [Member]
Available-for-sale securities	13,381	14,410
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| US Treasury Securities [Member]
Available-for-sale securities	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities	$ 2,914	$ 2,931

Fair value portion of asset recognized for present right to economic benefit.

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