Option Activity and Changes (Detail)	3 Months Ended
	Apr. 01, 2017 $ / shares shares
Shares
Options outstanding at December 31, 2016 | shares	2,740,364
Options granted | shares	30,625
Options cancelled and forfeited | shares	(21,405)
Options exercised | shares	(57,657)
Options outstanding at April 1, 2017 | shares	2,691,927
Options exercisable at April 1, 2017 | shares	1,783,825
Weighted Average Exercise Price
Options outstanding at December 31, 2016 | $ / shares	$ 7.00
Options granted | $ / shares	7.89
Options cancelled and forfeited | $ / shares	6.60
Options exercised | $ / shares	6.03
Options outstanding at April 1, 2017 | $ / shares	7.03
Options exercisable at April 1, 2017 | $ / shares	$ 7.78