Bridge Loan Financing - Summary of Estimated Fair Values of Outstanding Warrants Using Black-Scholes Option-Pricing Model (Detail) - Series C Warrants [Member] - $ / shares |
12 Months Ended | |
|---|---|---|
Feb. 04, 2014 |
Dec. 31, 2013 |
|
| Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ||
| Stock price | $ 32.66 | $ 8.84 |
| Expected option term (in years) | 4 years 4 months 24 days | 4 years 6 months |
| Expected volatility | 65.00% | 64.00% |
| Risk-free interest rate | 1.50% | 1.30% |
| Expected dividend yield | 0.00% | 0.00% |