| Intangible Assets | 
Intangible Assets 
The following table summarizes acquired intangible assets as follows: 
 
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   | 
   | 
April 1, 2017  | 
   | 
December 31, 2016  | 
 
(In thousands)  | 
 Weighted 
Average Life 
 | 
   | 
 Gross Carrying 
Amount 
 | 
   | 
 Accumulated 
Amortization 
 | 
   | 
 Gross Carrying 
Amount 
 | 
   | 
 Accumulated 
Amortization 
 | 
 
Patents  | 
4 Years  | 
   | 
$  | 
2,146  | 
 
  | 
   | 
$  | 
1,497  | 
 
  | 
   | 
$  | 
2,146  | 
 
  | 
   | 
$  | 
1,450  | 
 
  | 
 
Non-compete Agreement  | 
3 Years  | 
   | 
2,500  | 
 
  | 
   | 
1,104  | 
 
  | 
   | 
2,500  | 
 
  | 
   | 
979  | 
 
  | 
 
Trade Names  | 
7 Years  | 
   | 
10,199  | 
 
  | 
   | 
3,387  | 
 
  | 
   | 
10,189  | 
 
  | 
   | 
3,153  | 
 
  | 
 
Completed and Unpatented Technology  | 
6 Years  | 
   | 
24,135  | 
 
  | 
   | 
9,830  | 
 
  | 
   | 
24,118  | 
 
  | 
   | 
9,221  | 
 
  | 
 
Backlog  | 
-  | 
   | 
11,224  | 
 
  | 
   | 
11,224  | 
 
  | 
   | 
11,224  | 
 
  | 
   | 
11,224  | 
 
  | 
 
Customer Relationships  | 
11 Years  | 
   | 
97,075  | 
 
  | 
   | 
24,708  | 
 
  | 
   | 
97,046  | 
 
  | 
   | 
23,093  | 
 
  | 
 
Total Intangible Assets  | 
6 Years  | 
   | 
$  | 
147,279  | 
 
  | 
   | 
$  | 
51,750  | 
 
  | 
   | 
$  | 
147,223  | 
 
  | 
   | 
$  | 
49,120  | 
 
  | 
 
  
 
 
All acquired intangible assets other than goodwill and one trade name are being amortized. Amortization expense for acquired intangibles is summarized as follows: 
 
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   | 
Three Months Ended  | 
 
(In thousands)  | 
April 1,  2017  | 
   | 
April 2,  2016  | 
 
Amortization Expense  | 
$  | 
2,618  | 
 
  | 
   | 
$  | 
2,808  | 
 
  | 
 
  
 
 
Amortization expense for acquired intangible assets expected for 2017 and for each of the next five years is summarized as follows:
 
 
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(In thousands)  | 
   | 
 
2017  | 
$  | 
10,450  | 
 
  | 
 
2018  | 
10,133  | 
 
  | 
 
2019  | 
9,754  | 
 
  | 
 
2020  | 
9,198  | 
 
  | 
 
2021  | 
9,152  | 
 
  | 
 
2022  | 
8,756  | 
 
  | 
 
  
 
 
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