GOODWILL AND OTHER INTANGIBLE ASSETS

Goodwill

The Company accounts for goodwill in accordance with the authoritative guidance, which requires that goodwill and certain intangible assets are not amortized, but are subject to an annual impairment test. The Company performed a qualitative assessment in connection with its annual goodwill impairment test in the fourth quarter of 2017. As a result of the qualitative analysis, a quantitative impairment test was not deemed necessary. There was no impairment of goodwill or indefinite lived intangible assets as a result of the annual impairment test analysis completed during the fourth quarter of 2017. There were no changes in reporting units nor indicators of impairment during the three months ended June 30, 2018. See Note 5 for more information regarding the Company's acquisitions.

The following table presents the change in goodwill during the six months ended June 30, 2018 (in thousands):



	Balance at January 1, 2018		Additions			Other		Balance at June 30, 2018
Goodwill	$	1,614,494	$	47,944	(1)	$	—	$	1,662,438


(1)	Amount relates to preliminary purchase price allocation of goodwill associated with the 2018 Business Combination. See Note 5 for more information regarding the Company's acquisitions.

Intangible Assets

The Company has intangible assets which were primarily acquired in conjunction with business combinations and technology purchases. Intangible assets with finite lives are recorded at cost, less accumulated amortization. Amortization is computed over the estimated useful lives of the respective assets, generally three to seven years, except for patents, which are amortized over the lesser of their remaining life or ten years. In-process R&D is initially capitalized at fair value as an intangible asset with an indefinite life and assessed for impairment thereafter. When in-process R&D projects are completed, the corresponding amount is reclassified as an amortizable intangible asset and is amortized over the asset's estimated useful life.

Intangible assets consist of the following (in thousands):



	June 30, 2018				December 31, 2017
	Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization
Product related intangible assets	$	689,873	$	577,482	$	663,004	$	554,934
Other	226,323		196,725		222,923		189,041
Total	$	916,196	$	774,207	$	885,927	$	743,975

Amortization of product-related intangible assets, which consists primarily of product-related technologies and patents, was $11.5 million and $12.4 million for the three months ended June 30, 2018 and 2017, respectively, and $22.5 million and $25.5 million for the six months ended June 30, 2018 and 2017, respectively, and is classified as a component of Cost of net revenues in the accompanying condensed consolidated statements of income. Amortization of other intangible assets, which consist primarily of customer relationships, trade names and covenants not to compete was $4.0 million and $3.7 million for the three months ended June 30, 2018 and 2017, respectively, and $7.7 million and $7.3 million for the six months ended June 30, 2018 and 2017, respectively, and is classified as a component of Operating expenses in the accompanying condensed consolidated statements of income.

The Company monitors its intangible assets for indicators of impairment. If the Company determines impairment has occurred, it will write-down the intangible asset to its fair value. For certain intangible assets where the unamortized balances exceeded the undiscounted future net cash flows, the Company measures the amount of the impairment by calculating the amount by which the carrying values exceed the estimated fair values, which are based on projected discounted future net cash flows.

Estimated future amortization expense of intangible assets with finite lives as of June 30, 2018 is as follows (in thousands):



Year ending December 31,	Amount
2018 (remaining six months)	$	31,022
2019	39,719
2020	27,220
2021	13,232
2022	11,381
Thereafter	19,415
Total	$	141,989