Share-based compensation - Summary of Weighted Average Assumptions of Options Granted (Detail)	9 Months Ended
Sep. 30, 2020 Years $ / shares	Sep. 30, 2019 Years $ / shares
Disclosure of terms and conditions of share-based payment arrangement [abstract]
Average fair value of options granted (per option) \| $ / shares	$ 0.29
Expected life of options (years) \| Years	2.2
Expected forfeiture rate	1.00%

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]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2020-01-01
-Paragraph 47
-Subparagraph a
-Clause i
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_47_a_i&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_WeightedAverageSharePriceShareOptionsGranted2019
Namespace Prefix:	ifrs-full_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration