The portion of the valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from net operating loss carryforwards for which it is more likely than not that a tax benefit will not be realized.

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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Period Type:	instant

Income Taxes - Deferred Tax Assets (Liabilties) (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Net operating loss carryforwards
Valuation allowance
Operating loss carryforwards