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.

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The option life of share options granted.

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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]]

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Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

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The number of other equity instruments (ie other than share options) granted in a share-based payment arrangement.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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The weighted average exercise price of other equity instruments (ie other than share options) outstanding in a share-based payment arrangement. [Refer: Weighted average [member]]

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The weighted average fair value at the measurement date of granted equity instruments other than share options. [Refer: Weighted average [member]]

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Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

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Period which the right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Represents the number of free share award plans approved by the reporting entity during the period.

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Subscription premium price per share of other equity instruments granted in share-based payment arrangement.

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Shareholders' Equity - Characteristics of BSA share warrant plans (Details)	12 Months Ended
	Dec. 31, 2020 EUR (€) € / shares shares	Dec. 31, 2020 EUR (€) item € / shares shares	Dec. 31, 2020 EUR (€) € / shares shares	Dec. 31, 2019 € / shares	Dec. 31, 2018 € / shares	Jan. 01, 2020 item
Disclosure of terms and conditions of share-based payment arrangement [line items]
Issued				10,000
BSA share warrants
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of free share award plans \| item						3
BSA - 2017 plan
Disclosure of terms and conditions of share-based payment arrangement [line items]
Issued \| item		195,000
Number of shares per BSA \| shares	1	1	1
Subscription premium price per share ()	€ 0.534	€ 0.534	€ 0.534
Exercise price (in euros)	€ 6.675	€ 6.675	€ 6.675	€ 6.67	€ 6.67
Fair value per BSA at grant date () \| €	€ 2.47	€ 2.47	€ 2.47
Expected volatility			40.00%
Average life (years)			6
Risk free rate			0.22%
BSA - 2017 plan \| Tranche one
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	1 year
BSA - 2017 plan \| Tranche two
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	2 years
BSA - 2017 plan \| Tranche three
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	3 years
BSA - 2018 plan
Disclosure of terms and conditions of share-based payment arrangement [line items]
Issued					126,000
Exercise price (in euros)	€ 6.070	€ 6.070	€ 6.070	€ 6.07	€ 6.067
BSA 2018-1
Disclosure of terms and conditions of share-based payment arrangement [line items]
Issued \| item		126,000
Number of shares per BSA \| shares	1	1	1
Subscription premium price per share ()	€ 0.480	€ 0.480	€ 0.480
Exercise price (in euros)	€ 6.067	€ 6.067	€ 6.067
Fair value per BSA at grant date () \| €	€ 1.98	€ 1.98	€ 1.98
Expected volatility			40.00%
Average life (years)			6
Risk free rate			0.30%
BSA 2018-1 \| Maximum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	3 years
BSA 2018-1 \| Minimum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	1 year
BSA 2019
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	1 year
Issued \| item		10,000
Number of shares per BSA \| shares	1	1	1
Subscription premium price per share ()	€ 0.180	€ 0.180	€ 0.180
Exercise price (in euros)	€ 2.200	€ 2.200	€ 2.200
Fair value per BSA at grant date () \| €	€ 0.48	€ 0.48	€ 0.48
Expected volatility			40.00%
Average life (years)			5.5
Risk free rate			0.33%
BSA 2019 bis
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	1 year
Issued		10,000	10,000
Number of shares per BSA \| shares	1	1	1
Subscription premium price per share ()	€ 0.290	€ 0.290	€ 0.290
Exercise price (in euros)	€ 3.680	€ 3.680	€ 3.680
Fair value per BSA at grant date () \| €	€ 0.90	€ 0.90	€ 0.90
Expected volatility			40.00%
Average life (years)			6
Risk free rate			0.00%
BSA 2019 ter
Disclosure of terms and conditions of share-based payment arrangement [line items]
Issued		36,000	36,000
Number of shares per BSA \| shares	1	1	1
Subscription premium price per share ()	€ 0.290	€ 0.290	€ 0.290
Exercise price (in euros)	€ 3.680	€ 3.680	€ 3.680
Fair value per BSA at grant date () \| €	€ 0.90	€ 0.90	€ 0.90
Expected volatility			40.00%
Average life (years)			6
Risk free rate			0.00%
BSA 2019 ter \| Maximum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	3 years
BSA 2019 ter \| Minimum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	1 year