Intangible assets consist of trademark and customer lists acquired in the offer under the purchase method of accounting and are recorded at fair value net of accumulated amortization since the purchase date. Software license is recorded at cost. Amortization is calculated using the straight-line and accelerated methods over the following estimated useful lives:

 

		Useful life
Trademark		10 years
Customer lists		6 years
Software license		3 years

 

The carrying amount related to acquired intangible assets as of June 30, 2018 are as follows ($ in thousands):

 

Intangible assets at December 31, 2017		$	14,340
Addition			45
Amortization expense			(1,388)
Intangible assets at June 30, 2018		$	12,997

 

The future amortization of these intangible assets is as follows ($ in thousands):

 

		Trademark			Customer List			Software License			Total
Six Months Ended December 31, 2018		$	151		$	1,261		$	10		$	1,422
Year Ended December 31, 2019			300			2,500			15			2,815
Year Ended December 31, 2020			301			2,506			15			2,822
Year Ended December 31, 2021			300			2,500			5			2,805
Year Ended December 31, 2022			300			1,726			-			2,026
Thereafter			1,107			—			-			1,107
Total		$	2,459		$	10,493		$	45		$	12,997

 

The Company reviews its finite-lived intangible assets for impairment when events or changes in circumstances indicate that the carrying amount of a finite-lived intangible asset may not be recoverable. Recoverability of a finite-lived intangible asset is measured by a comparison of its carrying amount to the undiscounted future cash flows expected to be generated by the asset. If the asset is considered to be impaired, the impairment recognized is measured by the amount by which the carrying amount of the asset exceeds the fair value of the asset. There were no indicators of impairment during the six months ended June 30, 2018.