INTANGIBLE ASSETS AND GOODWILL (Tables)

12 Months Ended

Dec. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

The Company's intangible assets at December 31, 2018 and 2017 consisted of the following (in thousands):



December 31, 2018	Weighted average amortization period (years)	Cost		Accumulated amortization		Net carrying value
In-process research and development	*	$	5,600	$	—	$	5,600
Developed technology	6.91	182,880		63,187		119,693
Customer relationships	9.44	146,940		22,218		124,722
Trade names	5.20	2,000		624		1,376
Internal use software	3.00	730		730		—
	7.88	$	338,150	$	86,759	$	251,391



December 31, 2017	Weighted average amortization period (years)	Cost		Accumulated amortization		Net carrying value
In-process research and development	*	$	5,600	$	—	$	5,600
Developed technology	6.90	153,380		24,211		129,169
Customer relationships	9.32	120,840		12,015		108,825
Trade names	3.00	900		80		820
Internal use software	3.00	730		730		—
	7.77	$	281,450	$	37,036	$	244,414

* An in-process research and development intangible asset has an indefinite life until the product is generally available, at which time such asset is typically reclassified to developed technology.

Schedule of amortization expense related to intangible assets

Amortization expense for intangible assets for the years ended December 31, 2018, 2017 and 2016 was as follows (in thousands):



	Year ended December 31,						Statement of operations classification
	2018		2017		2016		Statement of operations classification
Developed technology	$	38,976	$	18,358	$	6,038	Cost of revenue - product
Customer relationships	10,203		4,145		1,462		Sales and marketing
Trade names	544		80		—		Sales and marketing
	$	49,723	$	22,583	$	7,500

Schedule of estimated future amortization expense for intangible assets

Estimated future amortization expense for the Company's intangible assets at December 31, 2018 was as follows (in thousands):



Years ending December 31,
2019	$	47,411
2020	46,552
2021	40,571
2022	34,156
2023	26,756
Thereafter	55,945
	$	251,391

Schedule of goodwill

The changes in the carrying value of the Company's goodwill in the years ended December 31, 2018 and 2017 were as follows (in thousands):



	Year ended December 31,
	2018			2017
Balance at January 1
Goodwill	$	338,822		$	52,499
Accumulated impairment losses	(3,106		)	(3,106		)
	335,716			49,393
Acquisition of Edgewater	48,053			—
Acquisition of GENBAND	—			285,825
Acquisition of Taqua and subsequent purchase accounting adjustments	—			498
Write-off of goodwill attributable to dissolved subsidiary	(114		)	—
Balance at December 31	$	383,655		$	335,716