Income Taxes (Details 2) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Unrecognized tax benefits, balance at the beginning of the period	$ 9,964	$ 14,450
Net changes in uncertain tax benefits	(2,953)	(3,559)
Unrecognized tax benefits, balance at the end of the period	7,011	$ 10,891
Expected change in unrecognized tax benefits in the next twelve months	$ (2,000)