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Note 17 - Commitments and Contingencies (Details Textual) $ in Millions					1 Months Ended		12 Months Ended
	Aug. 27, 2018 USD ($)	Aug. 27, 2018 CNY (¥)	Jul. 09, 2018 CNY (¥)	Jun. 29, 2018 EUR (€)	Apr. 30, 2018 USD ($)	Apr. 30, 2018 CNY (¥)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2015 USD ($)
Purchase Commitment, Remaining Minimum Amount Committed							$ 42.5	$ 58.9
Arezzo Revenue Agency [Member]
Loss Contingency, Estimate of Possible Loss								12.0
Claim by Setec Netzwerke AG [Member]
Litigation Settlement, Amount Awarded to Other Party \| €				€ 75,000
Claim by DG Yu Shing Industrial Development Company Limited [Member] \| Donugguan Transpower Electric Products Co., Ltd. [Member]
Loss Contingency, Number of Defendants									3
Loss Contingency, Damages Sought, Value									$ 3.2
Loss Contingency, Damages Awarded, Value					$ 3.2	¥ 20,133,174
Claim Against Jimmei Entities [Member] \| Donugguan Transpower Electric Products Co., Ltd. [Member]
Litigation Settlement, Amount Awarded from Other Party	$ 3.2	¥ 20,430,203	¥ 20,133,174
Capital Addition Purchase Commitments [Member]
Long-term Purchase Commitment, Amount							$ 2.8	$ 5.2