Annual report pursuant to Section 13 and 15(d)

Warrants - Summary of Placement Warrants Valuation Using Black-Scholes Pricing Model (Detail)

v2.4.1.9
Warrants - Summary of Placement Warrants Valuation Using Black-Scholes Pricing Model (Detail) (Warrant [Member])
12 Months Ended
Dec. 31, 2014
Warrant [Member]
 
Class of Warrant or Right [Line Items]  
Dividend yield 0.00%us-gaap_FairValueAssumptionsExpectedDividendRate
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_WarrantMember
Expected volatility 74.66%us-gaap_FairValueAssumptionsExpectedVolatilityRate
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_WarrantMember
Weighted average risk-free interest rate 1.61%us-gaap_FairValueAssumptionsRiskFreeInterestRate
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_WarrantMember
Expected term (years) 5 years