CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 30, 2017
Statement of Financial Position [Abstract]
Net of allowance for doubtful accounts	$ 866	$ 892
Preferred stock, par value (in usd per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in usd per share)	$ 0.001	$ 0.001
Common stock, authorized shares (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	153,988,000	149,471,000
Common stock, shares outstanding (in shares)	153,988,000	149,471,000