Summary of significant accounting policies - Intangible assets (Details) - Acquired software licenses	12 Months Ended
Dec. 31, 2020
Minimum
Disclosure of detailed information about intangible assets [line items]
Useful life in years	1 year
Maximum
Disclosure of detailed information about intangible assets [line items]
Useful life in years	3 years

The useful life, measured as period of time, used for intangible assets other than goodwill. [Refer: Intangible assets other than goodwill]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 38
-IssueDate 2020-01-01
-Paragraph 118
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_118_a&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration