Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Jan. 01, 2017	Oct. 02, 2016	Jul. 03, 2016	Apr. 03, 2016	Dec. 31, 2017	Jan. 01, 2017	Jan. 03, 2016
Net income (loss)	$ 52,868	$ (11,092)	$ (5,930)	$ 17,220	$ (10,126)	$ (2,404)	$ (9,052)	$ 17,915	$ 53,066	$ (3,667)	$ (12,510)
Components of other comprehensive income (loss), net of tax:
Foreign currency translation adjustments									1,010	420	(2,403)
Total components of other comprehensive income (loss), net of tax									1,010	420	(2,403)
Comprehensive income (loss)									$ 54,076	$ (3,247)	$ (14,913)