8. Intangible Assets

Our intangible assets are comprised of indefinite- and finite-lived intangible assets. We own the rights to both 3MHz of ATG spectrum in the nationwide 800 MHz Commercial Air-Ground Radiotelephone band (the “3 MHz FCC License”), which is used in the operation of our ATG network, and the 1 MHz FCC License acquired in the Airfone Acquisition. Together we refer to the 3 MHz FCC License and the 1 MHz FCC License as the “FCC Licenses”. While the FCC Licenses were issued with 10-year terms, such licenses are subject to renewal by the FCC, and renewals of licenses held by others have occurred routinely and at nominal cost. Moreover, we have determined that there are currently no legal, regulatory, contractual, competitive, economic, or other factors that limit the useful life of the FCC Licenses. As a result, the FCC Licenses are treated as indefinite-lived intangible assets which we do not amortize. We reevaluate the useful life of the FCC Licenses each year to determine whether events and circumstances continue to support an indefinite useful life. Our annual impairment assessment of the FCC Licenses for 2013, 2012, and 2011 indicated no impairment.

We amortize our finite-lived intangible assets on a straight-line basis over their estimated useful lives.

Our software relates to the development of internal use software which is used to run our network and support our service offerings. Software also includes software embedded in the equipment that we sell to our customers within the BA segment.

As of December 31 2013 and 2012, our goodwill balance, all of which related to our BA segment, was $0.6 million.

Our intangible assets, other than goodwill, as of December 31, 2013 and 2012 were as follows (in thousands, except for weighted average remaining useful life):


	Weighted Average Remaining Useful Life (in years)		As of December 31, 2013							As of December 31, 2012
	Weighted Average Remaining Useful Life (in years)		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Amortized intangible assets:
Software		3.2	$	58,689	$	(27,558	)	$	31,131	$	58,765	$	(35,263	)	$	23,502
Patents		5.6		500		—			500		—		—			—
Trademark/trade name ⁽¹⁾		4.3		3,072		(2,885	)		187		2,852		(2,852	)		—
Aircell Axxess technology		1.1		4,129		(3,827	)		302		4,129		(3,549	)		580
OEM and dealer relationships		3.1		6,724		(4,650	)		2,074		6,724		(3,978	)		2,746
Service customer relationships ⁽¹⁾		6.3		8,081		(1,710	)		6,371		981		(981	)		—

Total amortized intangible assets				81,195		(40,630	)		40,565		73,451		(46,623	)		26,828

Unamortized intangible assets:
FCC Licenses ⁽¹⁾				32,283		—			32,283		31,319		—			31,319

Total intangible assets			$	113,478	$	(40,630	)	$	72,848	$	104,770	$	(46,623	)	$	58,147

(1)

See Note 7, “Airfone Acquisition” for further information.

Amortization expense for the years ended December 31, 2013, 2012 and 2011 was $9.2 million, $7.4 million and $10.1 million, respectively.

Amortization expense for each of the next five years and thereafter is estimated to be as follows (in thousands):


Years ending December 31,	Amortization Expense
2014	$	11,730
2015	$	9,714
2016	$	7,926
2017	$	4,023
2018	$	2,635
Thereafter	$	4,537

Actual future amortization expense could differ from the estimated amount as the result of future investments and other factors.