| Note 7 - Income Taxes (Details Textual) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
| Jul. 01, 2018 | Jul. 02, 2017 | Jul. 01, 2018 | Jul. 02, 2017 | |
| Current Income Tax Expense (Benefit), Total | $ 196 | $ 168 | $ 306 | $ 295 | 
| Deferred Income Tax Expense (Benefit), Total | $ 38 | $ (14) | $ (46) | $ (148) | 
| X | ||||||||||
| 
- Definition Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 | 
| X | ||||||||||
| 
- Definition Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 |