Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Significant Accounting Policies (Narrative) (Details)

v3.8.0.1
Significant Accounting Policies (Narrative) (Details)
€ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
EUR (€)
Dec. 31, 2015
EUR (€)
Statement Line Items [Line Items]      
General and administrative expenses   € 2,201 € 1,044
Euro [Member]      
Statement Line Items [Line Items]      
Rate of exchange 0.835    
USD [Member]      
Statement Line Items [Line Items]      
Rate of exchange 1.00    
Bottom of range [Member]      
Statement Line Items [Line Items]      
Percentage of hedge 80.00%    
Top of range [member]      
Statement Line Items [Line Items]      
Percentage of hedge 125.00%