Note 6 - Leases - Balance Sheet Classifications (Details) - EUR (€) € in Thousands	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Lease Liability. Current	€ 70	€ 58
Amortization of right-of-use assets	58	42
Lease Liability, Noncurrent	504	572
Interest on lease liability	109	117
Lease Liability	574	630
Short term lease costs	21
Variable lease costs	29	10
Total cash paid to satisfy lease liability and building lease expense	€ 217	€ 169

Amount of interest expense on finance lease liability.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 53
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479589/842-20-55-53

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-4

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Amount of amortization expense attributable to right-of-use asset from finance lease.

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Amount of lease cost recognized by lessee for lease contract.

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Present value of lessee's discounted obligation for lease payments from operating lease.

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Present value of lessee's discounted obligation for lease payments from operating lease, classified as current.

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Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent.

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Amount of short-term lease cost, excluding expense for lease with term of one month or less.

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Amount of variable lease cost, excluded from lease liability, recognized when obligation for payment is incurred for finance and operating leases.

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