Intangible Assets and Goodwill

12 Months Ended

Dec. 31, 2017

Intangible Assets and Goodwill [Abstract]

5. INTANGIBLE ASSETS AND GOODWILL

The following table provides a summary of the Company’s intangible assets at December 31:



		2017				2016
	Estimated			Accumulated				Accumulated
	Useful Life	Cost		Amortization		Cost		Amortization
Fusion technology	10 years	$	9,242	$	3,697	$	9,242	$	2,773
Clamp & probe technology	3 years		829		829		829		829
SUBTLE access technology	5 years		2,179		981		2,179		538
IPR&D			44,021		—		44,021		—
Total		$	56,271	$	5,507	$	56,271	$	4,140

Amortization expense related to intangible assets with definite lives, which excludes the IPR&D asset, was $1,367, $1,644 and $1,303 for the years ended December 31, 2017, 2016 and 2015.

Future amortization expense related to intangible assets with definite lives is projected as follows:



2018	$	1,367
2019		1,367
2020		1,235
2021		924
2022		925
2023 and thereafter		925
Total	$	6,743

The following table provides a summary of the Company’s goodwill, which is not amortized, but rather tested annually for impairment:



Net carrying amount as of December 31, 2015	$	105,257
Additions (Impairments)		—
Net carrying amount as of December 31, 2016		105,257
Additions (Impairments)		—
Net carrying amount as of December 31, 2017	$	105,257