5. INTANGIBLES

In conjunction with the Merger, we recorded intangible assets of $21.1 million. Our intangible assets consisted of the following:


	Dollars in Thousands
	December 31, 2018
			Accumulated		Net Book
	Cost		Amortization		Value
Technology	$	18,990	$	1,424	$	17,566
Customer relationships		250		125		125
Backlog		200		200		—
Covenants not to compete		30		30		—
Trademark		40		30		10
IPR&D		1,590		—		1,590
	$	21,100	$	1,809	$	19,291


	Dollars in Thousands
	December 31, 2017
			Accumulated		Net Book
	Cost		Amortization		Value
Technology	$	18,990	$	475	$	18,515
Customer relationships		250		42		208
Backlog		200		100		100
Covenants not to compete		30		15		15
Trademark		40		10		30
IPR&D		1,590		—		1,590
	$	21,100	$	642	$	20,458


	Estimated Useful Life
Technology	20	years
Customer relationships	3	years
Backlog	1	year
Covenants not to compete	1	year
Trademark	2	years

Until our in-process research and development projects are completed, the assets are accounted for as indefinite-lived intangible assets and subject to impairment testing. For the year ended December 31, 2018, there was no impairment of IPR&D.

Amortization expense for intangible assets was $1.2 million during the year ended December 31, 2018 and $0.6 million during the year ended December 31, 2017. Amortization expense for intangible assets is expected to be $1.0 million, $1.0 million, $0.9 million, $0.9 million and $0.9 million for each of the years ending December 31, 2019, 2020, 2021, 2022 and 2023, respectively.