Restructuring Costs - Schedule of Restructuring Costs, Recorded in Restructuring Expense in Condensed Consolidated Statements of Operations, Incurred (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	$ 206	$ 10,137
KFAB Wafer Manufacturing Operations
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	206	10,137
KFAB Wafer Manufacturing Operations | Early Supply Contract Termination
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown		1,985
KFAB Wafer Manufacturing Operations | Cost of Equipment Relocation, Shutdown Cost and Other
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	220	3,591
KFAB Wafer Manufacturing Operations | Asset Retirement Obligation
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown		1,403
KFAB Wafer Manufacturing Operations | Retention Costs
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	$ (14)	$ 3,158