Supplemental Disclosure of Cash Flow Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Apr. 01, 2016
Cash paid during period:
Income taxes	$ 446	$ 1,001
Non-cash investing and financing activities:
Unrealized gain on short-term investments	36	85
Vested stock unit awards issued to settle accrued bonuses	6,910	6,334
Accrual for capital expenditures	$ 405	$ 223