OTHER INTANGIBLE ASSETS

Other intangible assets are comprised of the following:



	December 31, 2015							December 31, 2014
(in thousands)	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Definite-lived intangible assets:
Developed technology	$	87,000	$	(23,264	)	$	63,736	$	87,000	$	(931	)	$	86,069
Customer relationships	75,133		(47,149		)	27,984		89,203		(39,399		)	49,804
Strategic development	30,500		(6,585		)	23,915		30,500		(263		)	30,237
In-process research & development	12,700		(2,622		)	10,078		12,700		(105		)	12,595
Favorable contracts	11,000		(5,554		)	5,446		11,000		(4,907		)	6,093
Other	3,699		(356		)	3,343		3,719		(326		)	3,393
Slots gaming license	2,250		(1,125		)	1,125		2,250		(1,125		)	1,125
Table games license	2,493		(310		)	2,183		2,493		(180		)	2,313
	$	224,775	$	(86,965	)	$	137,810	$	238,865	$	(47,236	)	$	191,629
Indefinite-lived intangible assets:
Trademarks						225,729							225,729
Slots gaming rights						128,890							128,890
Illinois Horseracing Equity Trust						3,307							3,307
Other						417							417
Total						$	496,153						$	549,972

Amortization expense for definite-lived intangible assets was approximately $56.1 million in 2015, $13.3 million in 2014 and $12.2 million in 2013 and is classified in operating expense. We submitted payments of $2.3 million for 2015 and 2014 for annual license fees for Calder Casino. Payments are being amortized to expense over the annual license period.

Indefinite-lived intangible assets consist primarily of state gaming licenses in Maine, Mississippi and Florida, rights to participate in the Horse Racing Equity Fund and trademarks.

In 2015, we reduced our customer relationships intangible asset and accumulated amortization for TwinSpires by $14.0 million as this amount was fully amortized.

In 2014, we established definite-lived intangible assets of $162.9 million and indefinite-lived intangible assets of $200.0 million related to the Big Fish Games acquisition.

We performed our annual indefinite-lived intangible asset impairment analysis for 2015 in accordance with ASU No. 2012-02, Intangibles-Goodwill and Other: Testing Indefinite-Lived Intangible Assets for Impairment. This analysis included an assessment of quantitative factors to determine whether it is more likely than not that the fair values of the indefinite-lived intangible assets are less than the carrying amounts. We assessed our indefinite-lived intangible assets by performing fair value calculations for each of our indefinite-lived intangible assets. We concluded that the fair values of our indefinite-lived intangible assets exceeded the carrying values. Based on the annual indefinite-lived intangible asset impairment analysis for 2015 and 2014, we concluded that indefinite-lived intangible assets had not been impaired.

Future estimated aggregate amortization expense on existing definite-lived intangible assets for each of the next five fiscal years is as follows (in thousands):



Year Ended December 31,	Estimated Amortization Expense
2016	$	50,687
2017	$	36,760
2018	$	18,716
2019	$	16,638
2020	$	4,586

Future estimated amortization expense does not include additional payments of $2.3 million in 2016 and in each year thereafter for the ongoing amortization of future expected annual Florida slots gaming license fees not yet incurred or paid.