| Quarterly Key Indicators | Q1/2020 | Q4/2019 | Q3/2019 | Q2/2019 | 2019 | |
| Net sales, M€ | 6.7 | 8.2 | 6.7 | 8.7 | 31.2 | |
| Operating result before depreciation (EBITDA), M€ | 0.0 | 1.0 | 0.8 | 1.7 | 4.7 | |
| Operating result (EBIT), M€ | -0.4 | 0.7 | 0.5 | 1.4 | 3.4 | |
| of net sales, % | -6% | 8% | 7% | 16% | 11% | |
| Profit/loss before taxes, M€ | -0.4 | 0.6 | 0.5 | 1.4 | 3.3 | |
| of net sales, % | -7% | 7% | 7% | 16% | 10% | |
| Net profit/loss for the period, M€ | -0.4 | 1.3 | 0.5 | 0.8 | 3.9 | |
| of net sales, % | -7% | 16% | 7% | 10% | 13% | |
| Equity ratio, % | 64% | 61% | 63% | 60% | 61% | |
| Gearing, % | 21% | 19% | 6% | 17% | 19% | |
| Gross investments in fixed assets, M€ | 1.0 | 1.8 | 0.5 | 0.7 | 3.5 | |
| of net sales, % | 14% | 21% | 8% | 8% | 11% | |
| Personnel, end of the quarter | 139 | 132 | 130 | 124 | 132 | |
| Earnings/share (EPS), € | -0.07 | 0.19 | 0.07 | 0.20 | 0.59 | |
| Equity/share, € | 2.60 | 2.70 | 2.50 | 2.43 | 2.70 |