Significant Accounting Policies - Potential Dilutive Securities Excluded from the Computation of Dilutive Weighted Average Shares Outstanding (Detail) - shares |
3 Months Ended | |
|---|---|---|
Mar. 31, 2016 |
Mar. 31, 2015 |
|
| Dilutive Securities Included And Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
| Potential dilutive securities excluded from the computation of dilutive weighted average shares outstanding | 7,120,060 | 17,346,696 |
| Warrant [Member] | ||
| Dilutive Securities Included And Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
| Potential dilutive securities excluded from the computation of dilutive weighted average shares outstanding | 1,967,375 | 13,647,848 |
| Stock Options [Member] | ||
| Dilutive Securities Included And Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
| Potential dilutive securities excluded from the computation of dilutive weighted average shares outstanding | 5,152,685 | 3,698,848 |