Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant	$ (461)	$ (1,055)
Stock-based compensation	(1,866)	(1,903)
Total	20,053	19,734
Commodity derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	25,655	23,143
Commodity derivatives	(3,275)	(451)
Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant	0	0
Stock-based compensation	(1,287)	(1,267)
Total	(1,287)	(1,267)
Quoted Prices in Active Markets (Level 1) | Commodity derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Commodity derivatives	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant	0	0
Stock-based compensation	0	0
Total	22,380	22,692
Significant Other Observable Inputs (Level 2) | Commodity derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	25,655	23,143
Commodity derivatives	(3,275)	(451)
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant	(461)	(1,055)
Stock-based compensation	(579)	(636)
Total	(1,040)	(1,691)
Significant Unobservable Inputs (Level 3) | Commodity derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Commodity derivatives	$ 0	$ 0