Organization and Summary of Significant Accounting Policies - Fair Value Valuation (FY) (Details) - Significant Unobservable Inputs (Level 3) - Warrants - $ / shares	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Dividend yield	0.00%	0.00%
Weighted average fair value (USD per share)	$ 0.80	$ 0.49
Minimum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Risk-free interest rate	2.20%	1.64%
Volatility	89.00%	77.25%
Expected term (in years)	5 years 15 days	4 years 9 months
Maximum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Risk-free interest rate	2.20%	1.99%
Volatility	89.41%	81.03%
Expected term (in years)	5 years 2 months 1 day	6 years 2 months 1 day

Agreed upon price for the exchange of the underlying asset.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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Expected dividends to be paid to holders of the underlying shares or financial instruments (expressed as a percentage of the share or instrument's price).

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Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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