GOODWILL AND INTANGIBLE ASSETS, NET

Goodwill

Our $639.5 million goodwill balance consisted of $198.1 million of goodwill acquired through the November 2014 Lumara Health acquisition and $441.4 million acquired through the August 2015 CBR acquisition. As of March 31, 2017, we had no accumulated impairment losses related to goodwill.

Intangible Assets

As of March 31, 2017 and December 31, 2016, our identifiable intangible assets consisted of the following (in thousands):



	March 31, 2017								December 31, 2016
			Accumulated								Accumulated
	Cost		Amortization		Impairments		Net		Cost		Amortization		Impairments		Net
Amortizable intangible assets:
Makena base technology	$	797,100	$	149,652	$	—	$	647,448	$	797,100	$	128,732	$	—	$	668,368
CBR customer relationships	297,000		17,519		—		279,481		297,000		13,590		—		283,410
	1,094,100		167,171		—		926,929		1,094,100		142,322		—		951,778
Indefinite-lived intangible assets:
Makena IPR&D	79,100		—		—		79,100		79,100		—		—		79,100
CBR trade names and trademarks	65,000		—		3,700		61,300		65,000		—		3,700		61,300
Total intangible assets	$	1,238,200	$	167,171	$	3,700	$	1,067,329	$	1,238,200	$	142,322	$	3,700	$	1,092,178

As of March 31, 2017, the weighted average remaining amortization period for our finite-lived intangible assets was approximately 8.5 years.

The Makena base technology and IPR&D intangible assets were acquired in November 2014 in connection with our acquisition of Lumara Health. Amortization of the Makena base technology asset is being recognized using an economic consumption model over 20 years from the acquisition date, which we believe is an appropriate amortization period due to the estimated economic lives of the product rights and related intangibles.

The CBR intangible assets (i.e., the CBR customer relationships and trade names and trademarks) were acquired in August 2015 in connection with our acquisition of CBR. Amortization of the CBR customer relationships is being recognized using an estimated useful life of 20 years from the acquisition date, which we believe is an appropriate amortization period due to the estimated economic lives of the CBR intangible assets. As part of our 2016 annual impairment test, we recorded an impairment charge of $3.7 million in the fourth quarter of 2016 related to the impairment of a portion of the CBR trade names and trademarks indefinite-lived intangible asset based on a revised long-term revenue forecast for CBR.

Total amortization expense for the three months ended March 31, 2017 and 2016, was $24.8 million and $16.6 million, respectively. Amortization expense for the Makena base technology is recorded in cost of product sales in our condensed consolidated statements of operations. Amortization expense for the CBR customer relationships is recorded in selling, general and administrative expenses in our condensed consolidated statements of operations. We expect amortization expense related to our finite-lived intangible assets to be as follows (in thousands):



	Estimated
	Amortization
Period	Expense
Remainder of Year Ending December 31, 2017	$	95,051
Year Ending December 31, 2018	81,433
Year Ending December 31, 2019	48,283
Year Ending December 31, 2020	46,845
Year Ending December 31, 2021	46,767
Thereafter	608,550
Total	$	926,929