Intangible Assets

Intangible assets consisted of the following (in thousands):



	December 31,
	2018			2017			Estimated Useful Life
Customer relationships	$	4,335		$	4,335		5 Years
Affiliate network	994			994			12 Years
Trademarks	548			548			8 Years
	5,877			5,877
Accumulated amortization	(5,378		)	(5,251		)
Intangible assets, net	$	499		$	626

The Company assesses the impairment of purchased intangible assets subject to amortization when events and circumstances indicate that the carrying value of the assets might not be recoverable. Fair value of our intangible assets is determined using the relief from royalty methodology. This approach involves two steps: (a) estimating reasonable royalty rates for each intangible asset and (b) applying these royalty rates to a net revenue stream and discounting the resulting cash flows to determine fair value. This fair value is then compared with the carrying value of each intangible asset. If the carrying value of the intangible asset is greater than its implied fair value, an impairment in the amount of the excess is recognized and charged to operations. The determination of related estimated useful lives and whether or not these assets are impaired involves significant judgments, related primarily to the future profitability and/or future value of the assets. Changes in the Company’s strategic plan and/or other-than-temporary changes in market conditions could significantly impact these judgments and could require adjustments to recorded asset balances. Long-lived assets are evaluated for impairment at least annually, as well as whenever an event or change in circumstances has occurred that could have a significant adverse effect on the fair value of long-lived assets. The Company performed evaluations of intangible assets as of each quarter end during 2018 and determined that the fair value of the long-lived assets exceeded the carrying value, therefore no impairment charges were required for the year ended December 31, 2018.

Intangible assets with finite lives are amortized using the straight-line method over the estimated economic lives of the assets, which range from five years to twelve years in accordance with ASC Topic 350. Accumulated amortization as of December 31, 2018 consisted of $4,335,000 for customer relationships, $597,000 for affiliate network and $444,000 for trademarks. Related amortization expense was $127,000 and $683,000 for the years ended December 31, 2018 and 2017, respectively. Amortization expense for each of the next five succeeding years will be as follows (in thousands):



2019	$	127
2020	113
2021	69
2022	69
2023	69
Thereafter	52
Total	$	499