Income taxes - Summary of unrecognized deferred tax assets (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Unrecognized Deferred Tax Assets
Tax losses	$ 181,667	$ 169,498
Other deductible temporary differences	39,394	30,242
Total unrecognized deferred tax assets	$ 221,061	$ 199,740

The amount of deferred tax expense or income relating to the creation or reversal of temporary differences. [Refer: Temporary differences [member]; Deferred tax expense (income)]

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 12
-IssueDate 2020-01-01
-Paragraph 80
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_80_c&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_DeferredTaxExpenseIncomeRelatingToOriginationAndReversalOfTemporaryDifferences
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration