Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2015

Intangible Assets

Schedule of intangible assets

Intangible assets consist of the following (in thousands):

	As of		As of
	December 31, 2015		December 31, 2014
Patents issued	$	6,180	$	6,518
Patents pending		1,156		3,373
Trademarks		40		40
Total intangible assets		7,376		9,931
Less patent amortization		(1,407)		(1,990)
Intangible assets, net	$	5,969	$	7,941

Finite-lived Intangible Assets Amortization Expense

The following table presents patent amortization expense included in the Consolidated Statement of Operations (in thousands):

	Years Ended December 31,
	2015		2014		2013
Amortization expense	$	995	$	688	$	615

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense

Estimated future aggregate annual amortization expense for both issued and pending intangible assets is as follows (in thousands):

As of December 31:
2016	$	580
2017		490
2018		430
2019		397
2020		379
Thereafter		3,653
Total	$	5,929