Goodwill and Intangible Assets, Net

Goodwill

The following table presents the changes in the carrying amount of our goodwill (in thousands):



	Total
Balance as of December 31, 2017	$	12,357
Goodwill acquired	1,300
Other	—
Currency translation	(458		)
Balance as of September 30, 2018	$	13,199

Intangible Assets, Net

Intangible assets, carried at cost less accumulated amortization and amortized on a straight-lined basis, were as follows (in thousands):



	Weighted Average	September 30, 2018
	Amortization Life in Years	Cost		Accumulated Amortization		Net
Patents	10	$	18,906	$	11,839	$	7,067
Customer contracts	9	5,319		5,177		142
Non-contractual customer relationships	9	55,695		11,553		44,142
Trademarks	4	425		425		—
Trade name	15	7,310		1,462		5,848
Developed technology	11	81,848		13,280		68,568
Total amortized intangible assets		$	169,503	$	43,736	$	125,767

IPR&D		$	6,044	—		$	6,044

Total intangible assets		$	175,547	$	43,736	$	131,811



	Weighted Average	December 31, 2017
	Amortization Life in Years	Cost		Accumulated Amortization		Net
Patents	10	$	17,064	$	10,970	$	6,094
Customer contracts	9	5,319		4,892		427
Non-contractual customer relationships	9	55,080		6,562		48,518
Trademarks	4	425		425		—
Trade name	15	7,310		1,096		6,214
Developed technology	11	81,846		7,571		74,275
Total amortized intangible assets		$	167,044	$	31,516	$	135,528

IPR&D		$	8,225			$	8,225

Total intangible assets		$	175,269	$	31,516	$	143,753

Intangible assets with definite lives are amortized on a straight-line basis over their estimated useful lives. Intangible asset amortization expense was $4.1 million and $12.2 million for the three and nine months ended September 30, 2018, respectively, and $3.6 million and $10.9 million for the three and nine months ended September 30, 2017, respectively.

As of September 30, 2018 estimated annual amortization for our intangible assets for each of the next five years is approximately (in thousands):



Remainder of 2018	$	4,004
2019	16,013
2020	15,867
2021	15,578
2022	15,426
Thereafter	58,879
Total	$	125,767