Depreciation and amortisation on tangible and intangible assets of EUR 0.9 million in 2017, EUR 0.8 million in 2016 and EUR 0.8 million in 2015 is included in the following items in the statement of comprehensive income:
| (in EUR thousand) | 31.12.2017 | 31.12.2016 | 31.12.2015 | |||||||||
| Research and development costs | 707 | 689 | 691 | |||||||||
| General administrative costs | 142 | 127 | 113 | |||||||||
| Cost of sales | 17 | 9 | 8 | |||||||||
| Sales and marketing | 18 | 6 | - | |||||||||
| Depreciation and amortisation expense | 884 | 831 | 812 | |||||||||
Personnel costs
| (in EUR thousand) | 31.12.2017 | 31.12.2016 | 31.12.2015 | |||||||||
| Wages and salaries | 11,349 | 5,753 | 3,557 | |||||||||
| Social security charges | 1,627 | 908 | 482 | |||||||||
| Costs for pension schemes | 66 | 33 | 34 | |||||||||
| Total | 13,042 | 6,694 | 4,073 | |||||||||