Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Jan. 02, 2016
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	$ 316,086	$ 400,173
Gross Unrealized Gains	3	34
Gross Unrealized Losses	(546)	(674)
Fair Value	315,543	399,533
Cash equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	34,587	132,502
Fair Value	34,587	132,502
Cash equivalents [Member] | Money market funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	23,110	126,752
Fair Value	23,110	126,752
Cash equivalents [Member] | Time deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	11,477	5,677
Fair Value	11,477	5,677
Cash equivalents [Member] | Government and corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost		73
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value		73
Short-term investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	185,693	111,144
Gross Unrealized Gains	3	20
Gross Unrealized Losses	(108)	(105)
Fair Value	185,588	111,059
Short-term investments [Member] | Time deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	40,639	30,989
Fair Value	40,639	30,989
Short-term investments [Member] | Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	22,325	1,500
Gross Unrealized Losses	(24)	(2)
Fair Value	22,301	1,498
Short-term investments [Member] | Government and corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	122,729	78,655
Gross Unrealized Gains	3	20
Gross Unrealized Losses	(84)	(103)
Fair Value	122,648	78,572
Long-term investments [Member] | Government and corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	95,806	156,527
Gross Unrealized Gains		14
Gross Unrealized Losses	(438)	(569)
Fair Value	$ 95,368	$ 155,972