Other Financial Information - Other Long-term Liabilities (FY) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Deferred rent		$ 46	$ 76
Security deposit		12	0
Other long term liabilities, net	$ 26	$ 58	$ 76

The noncurrent portion of money or property received from customers that is to be returned upon satisfactory contract completion or as partial prepayment for goods or services to be provided in the future.

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Period Type:	instant

- Definition

For a classified balance sheet, the cumulative difference between the rental income or payments required by a lease agreement and the rental income or expense recognized on a straight-line basis, or other systematic and rational basis more representative of the time pattern in which use or benefit is granted or derived from the leased property, expected to be recognized in income or expense, by the lessor or lessee, respectively, more than one year after the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.26(c))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 25
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77902458&loc=d3e39927-112707

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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- Definition

Amount of liabilities classified as other, due after one year or the normal operating cycle, if longer.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant