Redeemable Convertible Preferred Shares - Assumptions to Estimated Fair Value of Warrants (Parenthetical) (Detail)
Apr. 24, 2014
Mar. 31, 2014
Mar. 05, 2014
Subscription Rights [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Probability of occurrence of event 100.00%   100.00%
Series E Warrants [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Probability of occurrence of event     100.00%
Series E Warrants [Member] | Convertible Redeemable Preferred Shares [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Probability of occurrence of event     100.00%
Initial Public Offering [Member] | Subscription Rights [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Probability of occurrence of event 80.00%   80.00%
Initial Public Offering [Member] | Series E Warrants [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Probability of occurrence of event     80.00%
Initial Public Offering [Member] | Series E Warrants [Member] | Convertible Redeemable Preferred Shares [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Probability of occurrence of event   80.00%  
Liquidation Event [Member] | Subscription Rights [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Probability of occurrence of event 10.00%   10.00%
Liquidation Event [Member] | Series E Warrants [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Probability of occurrence of event     10.00%
Liquidation Event [Member] | Series E Warrants [Member] | Convertible Redeemable Preferred Shares [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Probability of occurrence of event   10.00%  
Redemption Event [Member] | Subscription Rights [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Probability of occurrence of event 10.00%   10.00%
Redemption Event [Member] | Series E Warrants [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Probability of occurrence of event     10.00%
Redemption Event [Member] | Series E Warrants [Member] | Convertible Redeemable Preferred Shares [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Probability of occurrence of event   10.00%