| Intangible Assets | 
Intangible Assets 
The following table summarizes acquired intangible assets as follows: 
 
|  |  
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  
|   |   | July 2, 2016 |   | December 31, 2015 |  
| (In thousands) | Weighted Average Life |   | Gross Carrying Amount |   | Accumulated Amortization |   | Gross Carrying Amount |   | Accumulated Amortization |  
| Patents | 5 Years |   | $ | 2,146 | 
 |   | $ | 1,357 | 
 |   | $ | 2,146 | 
 |   | $ | 1,264 | 
 |  
| Non-compete Agreement | 4 Years |   | 2,500 | 
 |   | 729 | 
 |   | 2,500 | 
 |   | 479 | 
 |  
| Trade Names | 7 Years |   | 10,232 | 
 |   | 2,685 | 
 |   | 10,217 | 
 |   | 2,216 | 
 |  
| Completed and Unpatented Technology | 6 Years |   | 24,083 | 
 |   | 8,006 | 
 |   | 24,056 | 
 |   | 6,795 | 
 |  
| Backlog | Less than 1 Year |   | 11,627 | 
 |   | 11,202 | 
 |   | 11,202 | 
 |   | 10,793 | 
 |  
| Customer Relationships | 12 Years |   | 96,946 | 
 |   | 19,957 | 
 |   | 96,472 | 
 |   | 16,770 | 
 |  
| Total Intangible Assets | 6 Years |   | $ | 147,534 | 
 |   | $ | 43,936 | 
 |   | $ | 146,593 | 
 |   | $ | 38,317 | 
 | 
 All acquired intangible assets other than goodwill and one trade name are being amortized. Amortization expense for acquired intangibles is summarized as follows:   
|  |  
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  
|   | Six Months Ended |   | Three Months Ended |  
| (In thousands) | July 2, 2016
 |   | July 4, 2015
 |   | July 2, 2016
 |   | July 4, 2015
 |  
| Amortization Expense | $ | 5,607 | 
 |   | $ | 5,772 | 
 |   | $ | 2,799 | 
 |   | $ | 2,920 | 
 | 
 
Amortization expense for acquired intangible assets expected for 2016 and for each of the next five years is summarized as follows:
   
|  |  
|  |  |  |  |  
| (In thousands) |   |  
| 2016 | $ | 11,013 | 
 |  
| 2017 | 10,591 | 
 |  
| 2018 | 10,066 | 
 |  
| 2019 | 9,664 | 
 |  
| 2020 | 9,130 | 
 |  
| 2021 | 9,085 | 
 |  |