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Note 15 - Commitments and Contingencies (Details Textual) - USD ($) $ in Millions | 12 Months Ended | 252 Months Ended |  |
--- | --- | --- | --- | ---
Dec. 31, 2016 | Dec. 31, 2015 | Mar. 31, 2024 | Dec. 31, 1994
Arezzo Revenue Agency [Member] |  |  |  |
Loss Contingency, Estimate of Possible Loss |  |  | $ 12.0 |
EOS Claim From Principal Commissioner of Customs [Member] | EOS Power Panama Inc. [Member] |  |  |  |
Customs Duties and Imposed Fines | $ 0.9 |  |  | $ 1.4
Payment for Customs Duties and Imposed Fines and Penalties |  | $ 0.5 |  |
Indemnification Period (Year) | 7 years |  |  |

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