Fair Value Measurements (Details) - Recurring [Member] - USD ($) $ in Thousands | Jul. 02, 2016 | Jan. 02, 2016 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - current | | $ 6,567 |
Marketable debt securities - noncurrent | | 8,553 |
Marketable debt securities | | 15,120 |
Level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - current | | 0 |
Marketable debt securities - noncurrent | | 0 |
Marketable debt securities | | 0 |
Level 2 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - current | | 6,567 |
Marketable debt securities - noncurrent | | 8,553 |
Marketable debt securities | | 15,120 |
Level 3 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - current | | 0 |
Marketable debt securities - noncurrent | | 0 |
Marketable debt securities | | 0 |
Corporate bonds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - current | | 2,512 |
Marketable debt securities - noncurrent | | 5,001 |
Corporate bonds [Member] | Level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - current | | 0 |
Marketable debt securities - noncurrent | | 0 |
Corporate bonds [Member] | Level 2 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - current | | 2,512 |
Marketable debt securities - noncurrent | | 5,001 |
Corporate bonds [Member] | Level 3 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - current | | 0 |
Marketable debt securities - noncurrent | | 0 |
U.S. Agency bonds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - noncurrent | | 2,496 |
U.S. Agency bonds [Member] | Level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - noncurrent | | 0 |
U.S. Agency bonds [Member] | Level 2 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - noncurrent | | 2,496 |
U.S. Agency bonds [Member] | Level 3 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - noncurrent | | 0 |
Municipal bonds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - current | | 4,055 |
Marketable debt securities - noncurrent | | 1,056 |
Municipal bonds [Member] | Level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - current | | 0 |
Marketable debt securities - noncurrent | | 0 |
Municipal bonds [Member] | Level 2 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - current | | 4,055 |
Marketable debt securities - noncurrent | | 1,056 |
Municipal bonds [Member] | Level 3 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable debt securities - current | | 0 |
Marketable debt securities - noncurrent | | 0 |
Other Assets [Member] | Available-for-sale Securities [Member] | Level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable securities assets funding the deferred compensation plan | $ 1,900 | 1,600 |
Other Noncurrent Liabilities [Member] | Level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Deferred compensation plan liability | $ 1,900 | $ 1,600 |