Restructuring Costs - Schedule of Costs Accrued Related to Restructuring (Details) - KFAB Wafer Manufacturing Operations $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Restructuring Cost And Reserve [Line Items]
Costs accrued	$ 8,734
Restructuring costs paid	(7,430)
Balance at December 31, 2017	1,304
Early Contract Termination
Restructuring Cost And Reserve [Line Items]
Costs accrued	1,985
Restructuring costs paid	(1,985)
Retention Costs
Restructuring Cost And Reserve [Line Items]
Costs accrued	3,158
Restructuring costs paid	(2,499)
Balance at December 31, 2017	659
Equipment Relocation, Shutdown Cost and Other
Restructuring Cost And Reserve [Line Items]
Costs accrued	3,591
Restructuring costs paid	(2,946)
Balance at December 31, 2017	$ 645