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Share-Based Compensation - Summary of Performance-Based RSU (Detail) - 2018 performance shares [member] - EUR (€) | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017
Disclosure of Input of Model Used for Performance-Based RSU [Line Items] |  |
Fair value at grant date (in euros) | € 15.31 | € 11.52
Share price at grant date (in euros) | € 10.27 | € 7.50
Dividend yield | 0.00% | 0.00%
Expected volatility | 75.00% | 75.00%
Risk-free interest rate (US government bond yield) | 2.60% | 1.51%
Model used | Monte Carlo | Monte Carlo

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- Definition Expected dividend as percentage, other equity instruments granted. + References No definition available. + Details
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- Definition Expected volatility, other equity instruments granted. + References No definition available. + Details
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- Definition Fair value at measurement date other equity instruments granted per share. + References No definition available. + Details
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- Definition The description of the option pricing model used for share options granted. [Refer: Option pricing model [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2018-01-01 -Paragraph 47 -Subparagraph a -Clause i -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2018-03-01&anchor=para_47_a_i&doctype=Standard -URIDate 2018-03-16 + Details
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- Details
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