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Net Loss Per Share - Potentially Dilutive Securities Excluded from Diluted Net Loss Per Share (Detail) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per share attributable to common stockholders, Total	6,243,224	13,152,202
Shares of common stock subject to outstanding options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per share attributable to common stockholders, Total	1,940,010	1,881,416
Shares of common stock subject to outstanding common stock warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per share attributable to common stockholders, Total	3,633,565	4,509,926
Shares of common stock subject to convertible notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per share attributable to common stockholders, Total	0	6,092,105
Shares of common stock subject to contingent consideration [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per share attributable to common stockholders, Total	227,845	227,845
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per share attributable to common stockholders, Total	441,804	440,910

X

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

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- Definition

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+ References

No definition available.

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