Income Taxes, Tax Credit Carryforwards (Details) - Research and Development [Member] $ in Millions	12 Months Ended
Dec. 31, 2017 USD ($)
Federal [Member]
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 2.8
Federal [Member] \| Earliest Tax Year [Member]
Tax Credit Carryforward [Line Items]
Tax credit carryforward, expiration date	Dec. 31, 2020
Federal [Member] \| Latest Tax Year [Member]
Tax Credit Carryforward [Line Items]
Tax credit carryforward, expiration date	Dec. 31, 2031
State [Member]
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 2.4

The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319

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Expiration date of the tax credit carryforward, in CCYY-MM-DD format.

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