UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash	$ 15,150	$ 10,364
Accounts receivable, net	39,647	30,901
Prepaid expenses and other current assets	12,570	15,572
Total current assets	67,367	56,837
Property and equipment, at cost:
Oil and natural gas properties, successful efforts method	786,089	775,167
Support equipment and facilities	144,458	142,208
Other	9,553	9,102
Accumulated depreciation, depletion and amortization	(620,881)	(609,231)
Property and equipment, net	319,219	317,246
Long-term derivative instruments	0	873
Restricted investments	4,623	4,623
Operating lease - long term right-of-use asset	1,771	2,500
Other long-term assets	2,345	2,680
Total assets	395,325	384,759
Current liabilities:
Accounts payable	14,382	798
Revenues payable	19,159	22,563
Accrued liabilities (see Note 12)	26,060	22,677
Short-term derivative instruments	63,071	10,824
Total current liabilities	122,672	56,862
Long-term debt (see Note 7)	235,000	260,516
Asset retirement obligations	99,412	96,725
Long-term derivative instruments	17,739	847
Operating lease liability	301	266
Other long-term liabilities	7,576	3,280
Total liabilities	482,700	418,496
Commitments and contingencies (see Note 14)
Stockholders' equity (deficit):
Preferred stock, $0.01 par value: 50,000,000 shares authorized; no shares issued and outstanding at June 30, 2021 and December 31, 2020	0	0
Warrants, 2,173,913 warrants issued and outstanding at June 30, 2021 and December 31, 2020	4,788	4,788
Common stock, $0.01 par value: 250,000,000 shares authorized; 37,987,145 and 37,663,509 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively	381	378
Additional paid-in capital	424,814	424,104
Accumulated deficit	(517,358)	(463,007)
Total stockholders' deficit	(87,375)	(33,737)
Total liabilities and equity	$ 395,325	$ 384,759