CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 96,738	$ 22,130
Restricted cash - other	2,264	6,136
Accounts receivable, net	29,365	19,576
Prepaid expenses	1,279	2,890
Other current assets	80	80
Total current assets	129,726	50,812
Oil and natural gas properties, using full cost method of accounting
Proved	1,442,972	1,463,950
Unproved	12,905	17,964
Less: accumulated depreciation, depletion and impairment	(1,371,123)	(1,375,692)
Net oil and natural gas properties	84,754	106,222
Other property, plant and equipment, net	98,951	103,118
Other assets	358	680
Total assets	313,789	260,832
Current liabilities
Accounts payable and accrued expenses	46,778	51,426
Derivative contracts	4,129	0
Asset retirement obligation	16,099	16,467
Other current liabilities	600	984
Total current liabilities	67,606	68,877
Long-term debt	0	20,000
Asset retirement obligation	36,339	40,701
Other long-term obligations	1,727	3,188
Total liabilities	105,672	132,766
Commitments and Contingencies
Stockholders’ Equity
Common stock, $0.001 par value; 250,000 shares authorized; 36,674 issued and outstanding at September 30, 2021 and 35,928 issued and outstanding at December 31, 2020	37	36
Warrants	88,520	88,520
Additional paid-in capital	1,062,376	1,062,220
Accumulated deficit	(942,816)	(1,022,710)
Total stockholders’ equity	208,117	128,066
Total liabilities and stockholders’ equity	$ 313,789	$ 260,832