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Income Taxes (Income Tax Reconciliation) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Statutory rate	21.00%	34.00%	34.00%
State and local taxes	1.50%	1.50%	1.60%
Uncertain tax position	72.90%	0.00%	0.00%
Research and development credit	(48.30%)	0.00%	(7.50%)
Stock based compensation	(5.20%)	(13.40%)	0.30%
Nondeductible compensation	4.10%
Domestic production credit	0.00%	(14.30%)	(5.40%)
Other	(2.70%)	(1.50%)	0.60%
Effective rate	43.30%	6.30%	23.60%
Deferred re-measurement for rate change	0.00%	(1144.40%)	0.00%
Effective rate	43.30%	(1138.10%)	23.60%

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Effective Income Tax Rate, Prior to Tax Cut and Jobs Act of 2017, Continuing Operations

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Percentage of increase (decrease) in effective tax rate for measurement period adjustment from accounting for tax effect pursuant to Tax Cuts and Jobs Act of 2017.

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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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