INTANGIBLE ASSETS

As of December 31, 2017, the balances of amortizable intangible assets were as follows:



	Weighted-Average Amortization Period	Gross Intangible Assets		Accumulated Amortization			Net Intangible Assets
Patents	11.7 years	$	127	$	(54	)	$	73
License agreements		2,285		(269		)	2,016
Total amortizable assets		$	2,412	$	(323	)	$	2,089

As of December 31, 2016, the balances of amortizable intangible assets were as follows:



	Weighted-Average Amortization Period	Gross Intangible Assets		Accumulated Amortization			Net Intangible Assets
Patents	12.7 years	$	127	$	(47	)	$	80
License agreements		947		(29		)	918
Total amortizable assets		$	1,074	$	(76	)	$	998

Amortization expense was $246, $35 and $6 for the years ended December 31, 2017, 2016 and 2015, respectively. Future amortization expenses are expected as follows:



Year Ending December 31:
2018	$	383
2019	388
2020	359
2021	302
2022	219
Thereafter	438
	$	2,089

Licenses are tied to product launches and do not begin amortizing until the product is launched to the market. Anticipated market launch is in 2018 and 2019 for products for which we obtained licensing.

Trademarks are non-amortizing intangible assets which had a value of $260 for all periods presented.