Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2020

The changes in the carrying amount of goodwill for the years ended December 31, 2020 and 2019 were as follows:

	Goodwill
	(in thousands)
Balance as of December 31, 2018	$	632,370
Goodwill acquired		134,255
Goodwill divested		(2,682	)
Foreign currency translation		(2,790	)
Balance as of December 31, 2019	$	761,153
Goodwill acquired		162,747
Foreign currency translation		15,359
Balance as of December 31, 2020	$	939,259

The estimated useful lives of intangible assets are as follows:

Intangible Asset		Estimated Useful Life
Domain names		5 Years
Trademarks		1 to 5 Years
Acquired developed technology		4 to 7 Years
Customer relationships		2 to 5 Years
Patents		3 to 11 Years

Intangible assets consisted of the following:

	December 31, 2020
	Weighted- Average Remaining Useful Life - Years		Gross Carrying Amount		Accumulated Amortization		Net
	(in thousands, except years)
Domain names		1.6	$	414	$	283	$	131
Acquired developed technology		3.2		206,197		111,129		95,068
Patents		4.9		19,860		9,130		10,730
			$	226,471	$	120,542	$	105,929

	December 31, 2019
	Weighted- Average Remaining Useful Life - Years		Gross Carrying Amount		Accumulated Amortization		Net
	(in thousands except years)
Domain names		2.6	$	5,414	$	5,200	$	214
Trademarks		—		3,072		3,072		—
Acquired developed technology		3.6		175,414		95,921		79,493
Customer relationships		—		2,172		2,172		—
Patents		5.9		19,710		7,296		12,414
			$	205,782	$	113,661	$	92,121

As of December 31, 2020, the estimated intangible asset amortization expense for the next five years and thereafter is as follows: