Note 17 - Total Sales - Sales by Geographical Area (Details) - EUR (€) € in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues	€ 39,163	€ 35,686	€ 35,579
Asia [Member]
Revenues	14,119	13,461	10,427
FRANCE
Revenues	11,577	10,573	9,606
UNITED STATES
Revenues	2,048	1,748	3,418
Other geographical Areas [Member]
Revenues	€ 11,419	€ 9,904	€ 12,127

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
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