Fair Value Measurements - Financial Assets and Liabilities Accounted at Fair Value (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity contracts, Assets
Commodity contracts, Liabilities	125,773	2,808,278
Warrant derivative liability		2,808,278
Commodity Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity contracts, Assets
Commodity contracts, Liabilities	125,773
Fair Value Measurements Recurring [Member] | Fair Value Measurements, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant derivative liability
Fair Value Measurements Recurring [Member] | Fair Value Measurements, Level 1 [Member] | Commodity Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity contracts, Assets
Commodity contracts, Liabilities
Fair Value Measurements Recurring [Member] | Fair Value Measurements, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant derivative liability
Fair Value Measurements Recurring [Member] | Fair Value Measurements, Level 2 [Member] | Commodity Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity contracts, Assets
Commodity contracts, Liabilities	125,773
Fair Value Measurements Recurring [Member] | Fair Value Measurements, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant derivative liability		2,808,278
Fair Value Measurements Recurring [Member] | Fair Value Measurements, Level 3 [Member] | Commodity Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity contracts, Assets
Commodity contracts, Liabilities