Restructuring Costs - Schedule of Restructuring Costs, Recorded in Restructuring Expense in Condensed Consolidated Statements of Operations, Incurred (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	$ (320)	$ 2,231
KFAB Wafer Manufacturing Operations
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	(320)	2,231
KFAB Wafer Manufacturing Operations | Early Supply Contract Termination
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown		$ 2,231
KFAB Wafer Manufacturing Operations | Cost of Equipment Relocation
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	(306)
KFAB Wafer Manufacturing Operations | Retention Costs
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	$ (14)