Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities
Net loss	$ (24,139)	$ (151,384)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization	11,169	40,929
Stock-based compensation	1,088	(1,998)
Deferred taxes	0	(931)
Loss (gain) on derivative financial instruments	64,059	(80,029)
Settlements of derivative financial instruments	(12,398)	23,998
Impairment of oil and gas properties	0	199,908
Loss on disposal of property and equipment	0	83
Loss on sale of oil and gas properties	0	1,254
Non-cash interest expense	941	1,374
Change in fair value of warrants	0	(363)
Changes in operating assets and liabilities:
Accounts receivable	(5,001)	(189)
Prepaid expenses and other assets	(703)	(897)
Accounts payable and accrued expenses	(7,619)	(1,344)
Net cash provided by operating activities	27,397	30,411
Cash flows from investing activities
Acquisition of oil and gas properties	(1,612)	(1,714)
Development of oil and gas properties	(21,489)	(72,824)
Proceeds from sale of oil and gas properties	337	2,837
Purchases of other property and equipment	(13)	(636)
Net cash used in investing activities	(22,777)	(72,337)
Cash flows from financing activities
Proceeds from borrowings	0	48,157
Payments on borrowings	(10,121)	(8,109)
Net cash (used in) provided by financing activities	(10,121)	40,048
Net decrease in cash, cash equivalents and restricted cash	(5,501)	(1,878)
Cash, cash equivalents and restricted cash, beginning of the period	26,446	3,137
Cash, cash equivalents and restricted cash, end of the period	20,945	1,259
Supplemental information:
Cash paid for interest	7,496	21,036
Non-cash investing and financing activities:
Change in asset retirement obligation	(945)	24
Change in liabilities for capital expenditures	$ 15,326	$ (16,809)