Long-term Debt - Summary of Estimated Fair Values of Outstanding Warrants Using Black-Scholes Option-Pricing Model (Detail) - Hercules Warrants [Member]
Feb. 04, 2014
$ / shares
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]  
Stock price $ 32.66
Expected option term (in years) 3 years
Expected volatility 62.00%
Risk-free interest rate 0.70%
Expected dividend yield 0.00%