Derivative Financial Instruments - Significant Assumptions Utilized in Binomial Lattice Process (Detail) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Derivative [Line Items]
Quoted market price on valuation date	2.50
Level 3 [Member] | Derivative Financial Instruments, Assets [Member]
Derivative [Line Items]
Linked common shares	1,562,500	1,562,500	1,562,500
Warrant Group 1 [Member] | Level 3 [Member] | Minimum [Member]
Derivative [Line Items]
Range of market volatilities	15.20%
Risk free rates using zero coupon US Treasury Security rates	0.05%
Warrant Group 1 [Member] | Level 3 [Member] | Maximum [Member]
Derivative [Line Items]
Range of market volatilities	29.20%
Warrant Group 1 [Member] | Level 3 [Member] | Derivative Financial Instruments, Assets [Member]
Derivative [Line Items]
Linked common shares	525,000
Quoted market price on valuation date	2.29
Contractual exercise rate	2.3793
Term (years)	15 days
Warrant Group 2 [Member] | Level 3 [Member] | Minimum [Member]
Derivative [Line Items]
Range of market volatilities	69.70%	47.90%	59.90%
Risk free rates using zero coupon US Treasury Security rates	0.03%	0.05%	0.04%
Warrant Group 2 [Member] | Level 3 [Member] | Maximum [Member]
Derivative [Line Items]
Range of market volatilities	109.10%	66.10%	73.90%
Risk free rates using zero coupon US Treasury Security rates	0.56%	0.90%	0.67%
Warrant Group 2 [Member] | Level 3 [Member] | Derivative Financial Instruments, Assets [Member]
Derivative [Line Items]
Linked common shares	1,562,500	1,562,500	1,562,500
Quoted market price on valuation date	0.70	2.29	0.93
Contractual exercise rate	3.60	3.60	3.60
Term (years)	2 years 1 month 10 days	3 years 1 month 10 days	2 years 4 months 24 days
Custom lattice variable: Probability of exercisability (434,027 linked common shares)	0.00%	0.00%	0.00%