Intangible Assets, net

Intangible assets as of December 31, 2018 and 2017 comprised the following (in thousands):



	December 31, 2018							December 31, 2017
	Gross carrying amount		Accumulated amortization			Net carrying amount		Gross carrying amount		Accumulated amortization			Net carrying amount
Licensed intellectual property	$	4,750	$	(2,727	)	$	2,023	$	4,750	$	(2,126	)	$	2,624

In July 2012, the Company entered into a development collaboration and license agreement with Advanced Liquid Logic, Inc., or ALL, which was acquired by Illumina, Inc. in July 2013. Under the terms of the agreement, the Company established a collaborative program to develop in-vitro diagnostic products incorporating ALL’s proprietary electrowetting technology in conjunction with the Company’s electrochemical detection technology. The Company paid ALL an upfront license payment of $250,000 and agreed to pay up to $1,750,000 in potential additional milestone payments. In June 2017, the Company satisfied the final commercial milestone under this agreement requiring the payment of $500,000, which was recorded as licensed intellectual property.

Intellectual property licenses had a weighted average remaining amortization period of 3.43 years as of December 31, 2018. Amortization expense for intangible assets amounted to $601,000, $546,000, and $406,000 for the years ended December 31, 2018, 2017 and 2016, respectively.

Estimated future amortization expense for these licenses is as follows (in thousands):



Years Ending December 31,	Future Amortization Expense
2019	$	591
2020	591
2021	591
2022	250
Total	$	2,023