Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 5,460	$ 2,538
Accounts receivable
Oil, natural gas liquid and natural gas sales	12,041	12,289
Joint interest owners and others, net	1,396	794
Related parties	62	162
Derivative financial instruments	145	472
Prepaid expenses and other	1,653	2,365
Total current assets	20,757	18,620
Oil and gas properties, using the successful efforts method of accounting
Proved properties	834,493	750,226
Unproved properties	76,619	78,655
Other property and equipment	16,817	15,763
Less accumulated depletion, depreciation, amortization	(294,049)	(259,382)
Net property and equipment	633,880	585,262
Other non-current assets	2,086	2,918
Total assets	656,723	606,800
Current liabilities
Accounts payable	32,086	25,901
Accounts payable -- related parties	270	389
Oil, natural gas liquid and natural gas sales payable	11,254	8,747
Accrued liabilities	31,519	16,583
Derivative financial instruments	27,570	12,336
Total current liabilities	102,699	63,956
Long-term liabilities
Long-term debt	337,264	301,155
Asset retirement obligations	5,918	5,649
Deferred tax liabilities, net	106	8,105
Equity warrant liability	1,404	508
Equity warrant liability -- related parties	2,682	963
Derivative financial instruments	22,186	9,802
Other non-current liabilities	4,948	1,316
Total long-term liabilities	374,508	327,498
Commitments and contingencies (Note 12)
Stockholders' Equity
Series A-1 convertible participating preferred stock, $0.001 par value, 87,789 and 83,968 shares issued and outstanding, respectively	0	0
Additional paid-in capital	174,469	174,871
Accumulated deficit	(137,608)	(102,180)
Total stockholders' equity	179,516	215,346
Total liabilities and stockholders' equity	656,723	606,800
Class A Voting Common Stock
Stockholders' Equity
Common stock	142,655	142,655
Total stockholders' equity	142,655	142,655
Class B Non-Voting Common Stock
Stockholders' Equity
Common stock	$ 0	$ 0