Note 10 - Fair Value Measurements - Summary of Fair Value Measurements by Level (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024
Restricted cash and cash equivalents	$ 25,775		$ 27,150
Available-for-sale securities	120,167	$ 119,804
Corporate Debt Securities [Member]
Available-for-sale securities	57,223	57,471
Fair Value, Recurring [Member]
Cash and cash equivalents	90,386	76,121
Restricted cash and cash equivalents	25,775	20,801
Total financial assets	410,810	379,980
Fair Value, Recurring [Member] \| Equity Securities [Member]
Marketable equity securities	174,482	163,254
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member]
Available-for-sale securities	57,223	57,471
Fair Value, Recurring [Member] \| Asset-Backed Securities [Member]
Available-for-sale securities	14,263	14,410
Fair Value, Recurring [Member] \| US Treasury Securities [Member]
Available-for-sale securities	44,952	44,186
Fair Value, Recurring [Member] \| US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities	3,729	3,737
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	90,386	76,121
Restricted cash and cash equivalents	25,775	20,801
Total financial assets	377,254	348,824
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Equity Securities [Member]
Marketable equity securities	174,482	163,254
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Corporate Debt Securities [Member]
Available-for-sale securities	40,855	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	44,952	44,186
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities	804	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	33,556	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	16,368	13,815
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Asset-Backed Securities [Member]
Available-for-sale securities	14,263	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	2,925	2,931
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	0	0
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	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Asset-Backed Securities [Member]
Available-for-sale securities	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| US Treasury Securities [Member]
Available-for-sale securities	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities	$ 0	$ 0

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

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