Summary of Option Activity Under Stock Plans, Inducement Option and Winfrey Option (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 30, 2017 USD ($) $ / shares shares
Shares
Beginning Balance	5,113
Granted	1,302
Exercised	(275)
Cancelled	(256)
Ending Balance	5,884
Exercisable at December 30, 2017	4,214
Weighted-Average Exercise Price
Beginning Balance | $ / shares	$ 11.76
Granted | $ / shares	45.95
Exercised | $ / shares	13.94
Cancelled | $ / shares	35.86
Ending Balance | $ / shares	18.17
Options exercisable price per share | $ / shares	$ 10.60
Outstanding at December 30, 2017	7 years 3 months 19 days
Exercisable at December 30, 2017	7 years 4 months 24 days
Exercised	275
Cancelled	256
Outstanding at December 30, 2017 | $	$ 163,681
Exercisable at December 30, 2017 | $	$ 144,138