Effective income tax rate continuing operations before change in estimate of research and development credits.

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Income taxes line items.

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Stock warrants exercised.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Income Taxes (Details Textual) - USD ($) $ in Thousands, shares in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Corporate income tax rate			21.00%			35.00%
Recognized provisional tax expense						$ 2,300
Effective income tax rate	21.00%	38.00%	26.00%	30.00%
Income tax benefit	$ (4,391)	$ (8,806)	$ (16,188)	$ (19,641)
ASU 2016-09
Income Taxes [Line Items]
Income tax benefit				2,000
Warrant Exercise
Income Taxes [Line Items]
Income tax benefit				$ 5,000
Comcast
Income Taxes [Line Items]
Stock warrants exercised				1.4
Scenario, Forecast
Income Taxes [Line Items]
Effective income tax rate before change in estimate of research and development credits					29.00%
Effective income tax rate					27.00%