Cash, Cash Equivalents And Short Term Investments (Detail) - USD ($) $ in Thousands	Jan. 01, 2016	Jan. 02, 2015
Fair Value Measurements [Line Items]
Amortized Cost	$ 171,699	$ 154,380
Unrealized Gains	1	27
Unrealized Losses	(107)	(4)
Estimated Fair Value	171,593	154,403
U.S. Agency Securities
Fair Value Measurements [Line Items]
Amortized Cost	41,946
Unrealized Gains	1
Unrealized Losses	(106)
Estimated Fair Value	41,841
Cash
Fair Value Measurements [Line Items]
Amortized Cost	115,221	84,012
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	115,221	84,012
Money market securities
Fair Value Measurements [Line Items]
Amortized Cost	10,530	45,478
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	10,530	45,478
Total cash equivalents
Fair Value Measurements [Line Items]
Amortized Cost	10,530	45,478
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	10,530	45,478
Total cash and cash equivalents
Fair Value Measurements [Line Items]
Amortized Cost	125,751	129,490
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	125,751	129,490
State and municipal bonds
Fair Value Measurements [Line Items]
Amortized Cost	4,002	24,890
Unrealized Gains	0	27
Unrealized Losses	(1)	(4)
Estimated Fair Value	4,001	24,913
Total short-term investments
Fair Value Measurements [Line Items]
Amortized Cost	45,948	24,890
Unrealized Gains	1	27
Unrealized Losses	(107)	(4)
Estimated Fair Value	$ 45,842	$ 24,913