As of December 31, 2019 and 2018, the carrying values of our indefinite lived intangible assets are as follows (in thousands):


	2019		2018
Goodwill	$	186,697	$	188,781
In-process R&D		2,190		9,382
Procurement contracts and agreements		2,013		2,013
Trademarks		844		844

We monitor the phases of development of our acquired in-process R&D projects, including the risks associated with further development and the amount and timing of benefits expected to be derived from the completed projects. Incremental costs associated with development are charged to expense as incurred. Capitalized costs are amortized over the estimated useful life of the developed asset once completed. Our in-process R&D projects are reviewed for impairment annually, or more frequently, if events or changes in circumstances indicate that the asset might be impaired. The company did not record any impairment of indefinite lived intangible assets during the twelve months ended December 31, 2019 and 2018.

During the three months ended December 31, 2019, the Company received CE Mark for the E-nside multibranch stent graft system for the endovascular treatment of thoraco-abdominal aneurysms. The company reclassed $7.4 million related to the E-nside European business from in-process R&D and into defined lived intangible assets with a useful life of 20 years.

Based on our experience with similar agreements, we believe that our acquired procurement contracts and agreements have indefinite useful lives, as we expect to continue to renew these contracts for the foreseeable future. We believe that our trademarks have indefinite useful lives as we currently anticipate that these trademarks will contribute to our cash flows indefinitely.

As of December 31, 2019 and 2018, the value of our goodwill, all of which is related to our Medical Devices segment, is as follows (in thousands):



	2019		2018
Balance as of January 1,	$	188,781	$	188,305
Goodwill from JOTEC Acquisition		--		5,100
Revaluation of goodwill denominated in foreign currency		(2,084)		(4,624)
Balance as of December 31,	$	186,697	$	188,781

As of December 31, 2019 and 2018, gross carrying values, accumulated amortization, and approximate amortization periods of our definite lived intangible assets are as follows (dollars in thousands):


	Gross Carrying		Accumulated		Amortization
December 31, 2019	Value		Amortization		Period
Acquired technology	$	140,193		24,778	11	–	22	Years
Customer lists and relationships		31,131		6,581	13	–	22	Years
Distribution and manufacturing rights and know-how		13,826		3,005	5	–	15	Years
Patents		3,664		3,074			17	Years
Other		1,919		608	3	–	5	Years


	Gross Carrying		Accumulated		Amortization
December 31, 2018	Value		Amortization		Period
Acquired technology	$	134,999		16,815	11	–	22	Years
Customer lists and relationships		31,169		5,068	13	–	22	Years
Distribution and manufacturing rights and know-how		4,059		2,107	11	–	15	Years
Patents		3,656		2,970			17	Years
Other		1,154		235	3	–	5	Years

Amortization expense recorded in general, administrative, and marketing expenses on our Consolidated Statements of Operations and Comprehensive (Loss) Income for the years ended December 31 is as follows (in thousands):

As of December 31, 2019 scheduled amortization of intangible assets for the next five years is as follows (in thousands):



	2020		2021		2022		2023		2024		Total
Amortization expense	$	12,406	$	12,383	$	11,838	$	11,499	$	11,279	$	59,405