Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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- Definition

Value of input used to measure outstanding warrant and right embodying unconditional obligation requiring redemption by transferring asset at specified or determinable date or upon event certain to occur.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

Period between issuance and expiration of outstanding warrant and right embodying unconditional obligation requiring redemption by transferring asset at specified or determinable date or upon event certain to occur, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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Secured Convertible Notes Payable and Common Stock Purchase Warrants - Schedule of Inputs Used to Value the Series D Warrants (Detail)	Jun. 30, 2018	Dec. 31, 2017
Expected Life [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Expected life (in years)	5 years
Expected Life [Member] \| Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Expected life (in years)	3 months 29 days	9 months 25 days
Expected Life [Member] \| Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Expected life (in years)	6 years 4 months 24 days	4 years 10 months 17 days
'Expected Volatility [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	1.9410
'Expected Volatility [Member] \| Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	1.3269	1.3088
'Expected Volatility [Member] \| Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	3.7200	2.6692
Risk-free Interest Rates [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	0.0278
Risk-free Interest Rates [Member] \| Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	0.0199	0.0168
Risk-free Interest Rates [Member] \| Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	0.0292	0.0206
Series D-1 Warrants [Member] \| Expected Life [Member] \| Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Expected life (in years)	5 years 6 months
Series D-1 Warrants [Member] \| 'Expected Volatility [Member] \| Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	2.1500
Series D-1 Warrants [Member] \| Risk-free Interest Rates [Member] \| Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	0.0213
Series D-2 [101-113] Warrants [Member] \| Expected Life [Member] \| Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Expected life (in years)	6 years 6 months
Series D-2 [101-113] Warrants [Member] \| 'Expected Volatility [Member] \| Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	3.8900
Series D-2 [101-113] Warrants [Member] \| Risk-free Interest Rates [Member] \| Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	0.0230