Investments Accounted for Using the Equity Method - Summary of Aggregate Information of the Joint Venture that is Not Individually Material (Detail) $ in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2018 USD ($)	Dec. 31, 2018 TWD ($)	Dec. 31, 2017 TWD ($)	Dec. 31, 2016 TWD ($)
Joint venture that is not individually material [member]
Disclosure of joint ventures [line items]
The Group's share of net loss and total comprehensive loss for the year	$ (10,002)	$ (306,156)	$ (184,366)	$ (90,478)

The entity's share of the profit (loss) of joint ventures accounted for using the equity method. [Refer: Investments accounted for using equity method; Joint ventures [member]; Profit (loss)]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 85
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_85&doctype=Standard
-URIDate 2018-03-16

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