3. Income Taxes (Details 2) € in Thousands	Dec. 31, 2018 EUR (€)
United States
Net operating loss carry forwards	€ 76,271
United States | 2019
Net operating loss carry forwards	334
United States | 2020
Net operating loss carry forwards	493
United States | 2021
Net operating loss carry forwards	1,015
United States | 2022
Net operating loss carry forwards	1,901
United States | 2023
Net operating loss carry forwards	1,266
United States | 2024-2037
Net operating loss carry forwards	67,687
United States | Perpetual
Net operating loss carry forwards	3,575
Switzerland
Net operating loss carry forwards	611
Switzerland | 2019
Net operating loss carry forwards	466
Switzerland | 2020
Net operating loss carry forwards	114
Switzerland | 2021
Net operating loss carry forwards	0
Switzerland | 2022
Net operating loss carry forwards	0
Switzerland | 2023
Net operating loss carry forwards	0
Switzerland | 2024-2037
Net operating loss carry forwards	30
Switzerland | Perpetual
Net operating loss carry forwards	0
The Netherlands
Net operating loss carry forwards	3,626
The Netherlands | 2019
Net operating loss carry forwards	0
The Netherlands | 2020
Net operating loss carry forwards	251
The Netherlands | 2021
Net operating loss carry forwards	629
The Netherlands | 2022
Net operating loss carry forwards	0
The Netherlands | 2023
Net operating loss carry forwards	43
The Netherlands | 2024-2037
Net operating loss carry forwards	2,703
The Netherlands | Perpetual
Net operating loss carry forwards	€ 0