Note 3 - Investments and Fair Value Measurements - Fair Value Hierarchy for Cash Equivalents, Marketable Securities and Derivative Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Nov. 17, 2021
Contingent Consideration	$ 570	$ 720
Warrant liability	1,777	0
Total liabilities	117,158	87,728
Financial instrument liability	500	825	$ 900
Front Line Power Seller Notes [Member]
Front Line Power Construction seller financed debt, net of discount	68,753	86,183
Financial instrument liability - related to Syndicated debt	68,753	86,183
Syndicated Term Note [Member]
Front Line Power Construction seller financed debt, net of discount	536
Financial instrument liability - related to Syndicated debt	536
Seller Financed Notes Payable - Front Line Power Acquisition [Member]
Front Line Power Construction seller financed debt, net of discount	43,693
Financial instrument liability - related to Syndicated debt	43,693
Prepaid Advance Agreement [Member]
Front Line Power Construction seller financed debt, net of discount	1,829
Financial instrument liability - related to Syndicated debt	1,829
Fair Value, Inputs, Level 1 [Member]
Contingent Consideration	0	0
Warrant liability	0
Total liabilities	0	0
Financial instrument liability		0
Fair Value, Inputs, Level 1 [Member] \| Front Line Power Seller Notes [Member]
Front Line Power Construction seller financed debt, net of discount	0	0
Financial instrument liability - related to Syndicated debt	0	0
Fair Value, Inputs, Level 1 [Member] \| Syndicated Term Note [Member]
Front Line Power Construction seller financed debt, net of discount	0
Financial instrument liability - related to Syndicated debt	0
Fair Value, Inputs, Level 1 [Member] \| Seller Financed Notes Payable - Front Line Power Acquisition [Member]
Front Line Power Construction seller financed debt, net of discount	0
Financial instrument liability - related to Syndicated debt	0
Fair Value, Inputs, Level 1 [Member] \| Prepaid Advance Agreement [Member]
Front Line Power Construction seller financed debt, net of discount	0
Financial instrument liability - related to Syndicated debt	0
Fair Value, Inputs, Level 2 [Member]
Contingent Consideration	0	0
Warrant liability	0
Total liabilities	70,582	86,183
Financial instrument liability		0
Fair Value, Inputs, Level 2 [Member] \| Front Line Power Seller Notes [Member]
Front Line Power Construction seller financed debt, net of discount	68,753	86,183
Financial instrument liability - related to Syndicated debt	68,753	86,183
Fair Value, Inputs, Level 2 [Member] \| Syndicated Term Note [Member]
Front Line Power Construction seller financed debt, net of discount	0
Financial instrument liability - related to Syndicated debt	0
Fair Value, Inputs, Level 2 [Member] \| Seller Financed Notes Payable - Front Line Power Acquisition [Member]
Front Line Power Construction seller financed debt, net of discount	0
Financial instrument liability - related to Syndicated debt	0
Fair Value, Inputs, Level 2 [Member] \| Prepaid Advance Agreement [Member]
Front Line Power Construction seller financed debt, net of discount	1,829
Financial instrument liability - related to Syndicated debt	1,829
Fair Value, Inputs, Level 3 [Member]
Contingent Consideration	570	720
Warrant liability	1,777
Total liabilities	46,576	1,545
Financial instrument liability		825
Fair Value, Inputs, Level 3 [Member] \| Front Line Power Seller Notes [Member]
Front Line Power Construction seller financed debt, net of discount	0	0
Financial instrument liability - related to Syndicated debt	0	$ 0
Fair Value, Inputs, Level 3 [Member] \| Syndicated Term Note [Member]
Front Line Power Construction seller financed debt, net of discount	536
Financial instrument liability - related to Syndicated debt	536
Fair Value, Inputs, Level 3 [Member] \| Seller Financed Notes Payable - Front Line Power Acquisition [Member]
Front Line Power Construction seller financed debt, net of discount	43,693
Financial instrument liability - related to Syndicated debt	43,693
Fair Value, Inputs, Level 3 [Member] \| Prepaid Advance Agreement [Member]
Front Line Power Construction seller financed debt, net of discount	0
Financial instrument liability - related to Syndicated debt	$ 0

Amount of liability recognized arising from contingent consideration in a business combination.

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