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Fair Value Measurement - Schedule of Warrant Liability Measured At Fair Value Using Significant Unobservable Input (Level 3) (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
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Sep. 30, 2014 | Sep. 30, 2015 | Sep. 30, 2014
Fair Value Disclosures [Abstract] |  |  |
Change in fair value of warrant derivative liability | $ (1) | $ 1,366 | $ 16
Warrant exercised |  | $ (1,543) |

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- Definition Fair value of warrants exercised. + References No definition available. + Details
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- 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=56944662&loc=d3e3602-108585 + Details
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- References No definition available. + Details
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