Common Stock - Summary of Fair Value of Warrants Issued (Detail) - Series A and Series B Warrants issued in July 2014 Financing [Member] |
Dec. 31, 2018 |
Dec. 31, 2017 |
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| Risk-Free Interest Rates [Member] | ||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
| Warrant valuation assumptions | 0.0261 | 0.0182 |
| Expected Dividend Yield [Member] | ||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
| Warrant valuation assumptions | 0.00 | 0.00 |
| Expected Life [Member] | ||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
| Warrant valuation assumptions | 6 months | 1 year 6 months |
| Expected Volatility [Member] | ||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
| Warrant valuation assumptions | 1.11 | 0.86 |
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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. 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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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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. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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