F5 NETWORKS INC | 2013 | FY | 3

Balance Sheet Details
Goodwill
Changes in the carrying amount of Goodwill during fiscal years 2013 and 2012 are summarized as follows (in thousands):
 
Balance, September 30, 2011
$
234,691

Acquisition of Traffix Systems
113,210

Other
338

Balance, September 30, 2012
348,239

Acquisition of LineRate Systems
99,560

Acquisition of Versafe
75,937

Other
(9
)
Balance, September 30, 2013
$
523,727



Other Assets
Other assets consist of the following (in thousands):
 
 
 
September 30,
 
 
2013
 
2012
Acquired and developed technology and software development costs
 
$
59,453

 
$
18,129

Deposits and other
 
15,251

 
10,688

Restricted cash
 
860

 
179

 
 
$
75,564

 
$
28,996


Amortization expense related to other assets was approximately $4.3 million, $6.4 million, and $4.3 million for the fiscal years ended September 30, 2013, 2012 and 2011, respectively.
Intangible assets are included in other assets on the balance sheet and consist of the following (in thousands):
 
 
 
2013
 
2012
 
 
Gross
Carrying
Amount
 
Accumulated
Amortization
 
Net Carrying
Amount
 
Gross
Carrying
Amount
 
Accumulated
Amortization
 
Net Carrying
Amount
Acquired and developed technology and software development costs
 
$
99,463

 
$
(40,010
)
 
$
59,453

 
$
54,240

 
$
(36,111
)
 
$
18,129

Customer relationships
 
8,399

 
(3,123
)
 
5,276

 
5,379

 
(2,855
)
 
2,524

Patents and trademarks
 
3,044

 
(2,525
)
 
519

 
3,044

 
(2,464
)
 
580

Trade names
 
1,173

 
(250
)
 
923

 
263

 
(218
)
 
45

Non-compete covenants
 
2,160

 
(200
)
 
1,960

 
200

 
(200
)
 
—

 
 
$
114,239

 
$
(46,108
)
 
$
68,131

 
$
63,126

 
$
(41,848
)
 
$
21,278


Estimated amortization expense for intangible assets for the five succeeding fiscal years is as follows (in thousands):
 
2014
$
8,385

2015
8,372

2016
8,372

2017
5,954

2018
4,554

 
$
35,637



Accrued Liabilities
Accrued liabilities consist of the following (in thousands):
 
 
 
September 30,
 
 
2013
 
2012
Payroll and benefits
 
$
73,461

 
$
61,720

Sales and marketing
 
3,746

 
4,407

Income tax accruals
 
4,196

 
8,621

Other
 
11,205

 
11,661

 
 
$
92,608

 
$
86,409

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