The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Remaining amortization period of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value.

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Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Finite-lived Intangible Assets [Roll Forward]
Net carrying value Patent Portfolios, net			$ 3,578
Amortization expenses	$ (346)	$ (346)	(1,027)	$ (1,027)
Impairment Charges Patent Portfolios, net	$ 1,051		$ 1,051
Weighted average amortization period (years)			1 year
Patents [Member]
Finite-lived Intangible Assets [Roll Forward]
Net carrying value Patent Portfolios, net			$ 1,500	$ 3,578	$ 3,578
Amortization expenses			(1,027)
Impairment Charges Patent Portfolios, net			$ 1,051
Weighted average amortization period (years)			2 years 8 months 1 day		1 year