Net Loss Per Share - Numerators and Denominators of Basic and Diluted Net Income (Loss) Per Share Computations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Numerator:
Net loss	$ (2,913)	$ (31,500)	$ (16,607)	$ (55,527)
Denominator:
Basic and diluted	85,304	80,590	84,616	80,203
Net loss per share:
Basic and diluted	$ (0.03)	$ (0.39)	$ (0.20)	$ (0.69)