Financial Assets at Amortized Cost - Schedule of Income from Financial Assets at Amortized Cost (Detail) $ in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2019 TWD ($)	Dec. 31, 2018 TWD ($)	Dec. 31, 2019 USD ($)
Financial Instruments At Amortised Cost Category[abstract]
Time deposits	$ 168,970	$ 169,168
Time deposits		30,715
Restricted bank deposits	68,450	68,388
Non-current financial assets at amortized cost	68,450	99,103	$ 2,289
Interest income	$ 4,467	$ 920

The amount of revenue arising from interest for financial assets that are measured at amortised cost. [Refer: Interest income; Financial assets at amortised cost]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 20
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_20_b&doctype=Standard
-URIDate 2019-03-27

Name:	ifrs-full_InterestIncomeForFinancialAssetsMeasuredAtAmortisedCost
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration