Goodwill and Intangible Assets

12 Months Ended

Dec. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Intangible Assets

Goodwill and Intangible Assets

Goodwill balances are presented below (in thousands):

	Carrying Amount
Balance as of December 31, 2016	$	82,534
Goodwill acquired	39,668
Foreign currency translation adjustments	6,526
Balance as of December 31, 2017	128,728
Goodwill acquired	26,063
Foreign currency translation adjustments	(5,946		)
Balance as of December 31, 2018	$	148,845

Intangible assets consist of the following (in thousands):

	December 31,			December 31,
	2018			2017
Developed technology	$	114,395		$	102,349
Patents	57,180			31,030
Other	650			1,575
Total intangible assets	172,225			134,954
Less: accumulated amortization	(71,643		)	(48,038		)
Net carrying amount	$	100,582		$	86,916

Apart from the business combinations described in Note 5, we acquired $26.2 million and $13.4 million of intangible assets during the years ended December 31, 2018 and 2017, respectively. Weighted-average useful life for the intangible assets acquired during the year ended December 31, 2018 and 2017 is approximately seven years and ten years, respectively.

Amortization expense for intangible assets was approximately $25.2 million, $19.7 million, $15.1 million for the years ended December 31, 2018, 2017 and 2016, respectively.

The following table presents the estimated future amortization expense related to intangible assets held at December 31, 2018 (in thousands):

Years Ending December 31,
2019	$	29,037
2020	19,447
2021	17,521
2022	13,608
2023	7,739
Thereafter	13,230
Total future amortization expense	$	100,582