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Summary of Significant Accounting Policies - Securities Excluded from the Computation of Potentially Dilutive Securities (Detail) - shares | 9 Months Ended
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Sep. 30, 2015 | Sep. 30, 2014
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |  |
Antidilutive securities excluded from computation of earnings per share, amount | 28,121,031 | 25,296,098
Series B Convertible Preferred Stock |  |
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |  |
Antidilutive securities excluded from computation of earnings per share, amount |  | 8,888,597
Series C Convertible Preferred Stock |  |
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |  |
Antidilutive securities excluded from computation of earnings per share, amount |  | 5,789,699
Class B Common Shares Not Exercised |  |
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |  |
Antidilutive securities excluded from computation of earnings per share, amount |  | 5,509,925
Employee Stock Option |  |
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |  |
Antidilutive securities excluded from computation of earnings per share, amount | 9,811,356 | 3,055,469
Outstanding Restricted Stock Units |  |
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |  |
Antidilutive securities excluded from computation of earnings per share, amount | 485,150 |
Outstanding Warrants |  |
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |  |
Antidilutive securities excluded from computation of earnings per share, amount | 17,824,525 | 2,052,408

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- 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 -Glossary Antidilution -URI http://asc.fasb.org/extlink&oid=6505113 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Diluted Earnings Per Share -URI http://asc.fasb.org/extlink&oid=6510752 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Contingent Stock Agreement -URI http://asc.fasb.org/extlink&oid=6508534 Reference 4: 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 + Details
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- Definition 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. + References No definition available. + Details
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