As of June 30, 2021 and December 31, 2020 the carrying values of our indefinite lived intangible assets were as follows (in thousands):


	June 30,		December 31,
	2021		2020
Goodwill	$	255,484	$	260,061
In-process R&D		2,317		2,392
Procurement contracts and agreements		2,013		2,013
Trademarks		765		765

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 June 30, 2021 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.

As of June 30, 2021 and December 31, 2020 our entire goodwill balance was related to our Medical devices segment.

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. As of June 30, 2021 and December 31, 2020 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
June 30, 2021	Value		Amortization		Period
Acquired technology	$	218,678	$	41,655	11	–	22	Years
Customer lists and relationships		31,246		8,880	13	–	22	Years
Distribution and manufacturing rights and know-how		14,392		6,378	5	–	15	Years
Patents		4,037		3,127			17	Years
Other		3,854		1,422	4	–	5	Years

	Gross Carrying		Accumulated		Amortization
December 31, 2020	Value		Amortization		Period
Acquired technology	$	222,182	$	36,091	11	–	22	Years
Customer lists and relationships		31,316		8,132	13	–	22	Years
Distribution and manufacturing rights and know-how		14,728		5,349	5	–	15	Years
Patents		3,966		3,113			17	Years
Other		3,453		1,073	4	–	5	Years

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


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
Amortization expense	$	4,238	$	3,000	$	8,498	$	6,033

As of June 30, 2021 scheduled amortization of intangible assets for the next five years is as follows (in thousands):


	Remainder
	of 2021		2022		2023		2024		2025		2026		Total
Amortization expense	$	8,489		16,433		15,928		15,560		13,401		12,941	$	82,752