Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity warrant liability	$ (508)	$ (1,565)
Equity warrant liability - related parties	(963)	(2,994)
Stock appreciation rights	(314)
Total	(23,451)	(6,939)
Commodity Derivatives
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	472	1,730
Liabilities	(22,138)	(4,110)
Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	(21,666)	(2,380)
Significant Other Observable Inputs (Level 2) | Commodity Derivatives
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	472	1,730
Liabilities	(22,138)	(4,110)
Significant Unobservable Inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity warrant liability	(508)	(1,565)
Equity warrant liability - related parties	(963)	(2,994)
Stock appreciation rights	(314)
Total	$ (1,785)	$ (4,559)