Acquired intangible long-lived assets are being amortized as follows (in thousands):
 
Weighted Average Amortization Period (in years)
 
Gross Carrying Amount as of
December 31, 2016
 
Accumulated
Amortization
 
Accumulated Impairment Loss
 
Net Carrying
Value as of
December 31, 2016
Trademarks
15
 
$
7,100

 
$
(1,631
)
 
$
(4,179
)
 
$
1,290

Existing technology
13
 
12,600

 
(4,141
)
 
(4,328
)
 
4,131

Customer relationships
11
 
33,500

 
(12,819
)
 
(10,751
)
 
9,930

Patents
8
 
6,316

 
(713
)
 
—

 
5,603

Total Intangible Assets
 
 
$
59,516

 
$
(19,304
)
 
$
(19,258
)
 
$
20,954


 
Weighted Average Amortization Period (in years)
 
Gross Carrying
Amount as of
December 31, 2015
 
Accumulated
Amortization
 
Accumulated Impairment Loss
 
Net Carrying
Value as of
December 31, 2015
Trademarks
15
 
$
7,100

 
$
(1,492
)
 
$
(4,179
)
 
$
1,429

Existing technology
13
 
12,600

 
(3,577
)
 
(4,328
)
 
4,695

Customer relationships
11
 
33,500

 
(10,957
)
 
(10,751
)
 
11,792

Patents
8
 
285

 
(113
)
 
—

 
172

Total Intangible Assets
 
 
$
53,485

 
$
(16,139
)
 
$
(19,258
)
 
$
18,088