Share based payment arrangements - Inputs used in measurement (Details) $ / shares in Units, € in Thousands	Apr. 12, 2018 USD ($) $ / shares	Apr. 07, 2017 USD ($) $ / shares	Apr. 07, 2017 EUR (€)
Share based payment arrangements
Share price at grant date (in dollars per share)	$ 16.15	$ 13.80
Exercise price (in dollars per share)	$ 16.15	$ 13.90
Expected volatility (as a percent)	58.40%		55.00%
Expected dividends \| €			€ 0
Risk-free interest rate (as a percent)	2.85%		2.49%
Fair value at grant date (in dollars per share) \| $	$ 9.74	$ 8.00

The expected volatility of the share price used to calculate the fair value of the share options granted. Expected volatility is a measure of the amount by which a price is expected to fluctuate during a period. The measure of volatility used in option pricing models is the annualised standard deviation of the continuously compounded rates of return on the share over a period of time.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2019-01-01
-Paragraph 47
-Subparagraph a
-Clause i
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2019-en-r&anchor=para_47_a_i&doctype=Standard
-URIDate 2019-03-27

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- Definition

The implied yield currently available on zero-coupon government issues of the country in whose currency the exercise price for share options granted is expressed, with a remaining term equal to the expected term of the option being valued (based on the option's remaining contractual life and taking into account the effects of expected early exercise). [Refer: Government [member]]

+ References

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- References

No definition available.

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- Definition

The exercise price of share options granted.

+ References

+ Details

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- Definition

The amount of an expected dividend used to calculate the fair value of share options granted.

+ References

+ Details

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- Definition

The weighted average fair value of share options granted during the period at the measurement date. [Refer: Weighted average [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2019-01-01
-Paragraph 47
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2019-en-r&anchor=para_47_a&doctype=Standard
-URIDate 2019-03-27

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- Definition

The weighted average share price used as input to the option pricing model to calculate the fair value of share options granted. [Refer: Option pricing model [member]; Weighted average [member]]

+ References

+ Details

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