Income Taxes - Summary of Income Tax Examinations (Details)	12 Months Ended
	Sep. 30, 2016
United States | Minimum
Income Tax Examination [Line Items]
Open Tax Year	2011
United States | Maximum
Income Tax Examination [Line Items]
Open Tax Year	2016
China | Minimum
Income Tax Examination [Line Items]
Open Tax Year	2006
China | Maximum
Income Tax Examination [Line Items]
Open Tax Year	2016
South Korea | Minimum
Income Tax Examination [Line Items]
Open Tax Year	2010
South Korea | Maximum
Income Tax Examination [Line Items]
Open Tax Year	2016
Taiwan | Minimum
Income Tax Examination [Line Items]
Open Tax Year	2011
Taiwan | Maximum
Income Tax Examination [Line Items]
Open Tax Year	2016