As of September 30, 2020 and December 31, 2019 the carrying values of our indefinite lived intangible assets were as follows (in thousands):

We monitor the phases of development of our acquired in-process research and development 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 research and development projects are reviewed for impairment annually, or more frequently, if events or changes in circumstances indicate that the asset might be impaired.

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 our trademarks will contribute to our cash flows indefinitely.

We evaluate our goodwill and non-amortizing intangible assets for impairment on an annual basis during the fourth quarter of the year, and, if necessary, during interim periods if factors indicate that an impairment review is warranted. As of

September 30, 2020 we concluded that our assessment of current factors did not indicate that goodwill or non-amortizing intangible assets are more likely than not to be impaired. We will continue to evaluate the recoverability of these non-amortizing intangible assets in future periods as necessary.

The goodwill balance increased during the nine months ended September 30, 2020 as a result of the goodwill recorded in connection with the Ascyrus acquisition as further described in Note 2 above. As of September 30, 2020 and December 31, 2019 our entire goodwill balance was related to our Medical Devices segment.


	Medical Devices Segment
Balance as of December 31, 2019	$	186,697
Ascyrus acquisition		62,724
Revaluation of goodwill denominated in foreign currency		4,574
Balance as of September 30, 2020	$	253,995

Definite Lived Intangible Assets

The definite lived intangible balance includes balances related to acquired technology, customer relationships, distribution and manufacturing rights and know-how, patents and other definite lived intangible assets. The acquired technology balance increased $72.6 million during the nine months ended September 30, 2020 related to developed technology acquired as a result of the Ascyrus acquisition as further described in Note 2 above. As of September 30, 2020 and December 31, 2019 the gross carrying values, accumulated amortization, and approximate amortization period of our definite lived intangible assets were as follows (in thousands):


	Gross Carrying		Accumulated		Amortization
September 30, 2020	Value		Amortization		Period
Acquired technology	$	217,085	$	32,075	11	–	22	Years
Customer lists and relationships		31,215		7,733	13	–	22	Years
Distribution and manufacturing rights and know-how		14,239		4,678	5	–	15	Years
Patents		3,888		3,104			17	Years
Other		2,712		903	4	–	5	Years

	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

Amortization Expense

The following is a summary of amortization expense as recorded in general, administrative, and marketing expenses on our Summary Consolidated Statement of Operations and Comprehensive Income (Loss) (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2020		2019		2020		2019
Amortization expense	$	3,397	$	2,660	$	9,430	$	7,796

As of September 30, 2020 scheduled amortization of intangible assets for the next five years is as follows (in thousands):


	Remainder
	of 2020		2021		2022		2023		2024		2025		Total
Amortization expense	$	4,127		16,506		15,959		15,486		15,160		13,079	$	80,317