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Common Stock and Warrants - Summary of Warrants Accounts for as Liabilities (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair value of warrants at beginning of period	$ 6,941	$ 2,857
Exercise of warrants	(2,509)
Change in fair value of warrants during the period	(1,954)	354
Fair value of warrants at end of period	$ 2,478	$ 3,211

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- Definition

Fair value of warrants liability.

+ References

No definition available.

+ Details

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- Definition

Fair value of warrants liability exercise.

+ References

No definition available.

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X

- Definition

Amount of expense (income) related to adjustment to fair value of warrant liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section 25
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=6939902&loc=d3e20148-110875

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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