Restructuring Costs - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost And Reserve [Line Items]
Assets impairement related to KFAB shut-down	$ 2,211	$ 114	$ 1,672
KFAB Wafer Manufacturing Operations
Restructuring Cost And Reserve [Line Items]
Restructuring activities description	In February 2017, the Company announced its plan to transfer its wafer fabrication operation at KFAB to other Company-owned wafer fabrication plants and external foundries. The Company ceased production operations at KFAB late in third quarter 2017 and vacated and returned the premises in November 2017.
Proceeds from insurance settlement	$ 6,500
Assets impairement related to KFAB shut-down	1,900
Additional asset retirement obligations related to restructuring	1,403
Restructuring costs relating to KFAB shutdown	8,734
KFAB Wafer Manufacturing Operations | Asset Retirement Obligation Amortization
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	1,400
KFAB Wafer Manufacturing Operations | Cost of Goods Sold
Restructuring Cost And Reserve [Line Items]
Proceeds from insurance settlement	4,500
KFAB Wafer Manufacturing Operations | Other Income
Restructuring Cost And Reserve [Line Items]
Proceeds from insurance settlement	$ 2,000