Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities
Net loss	$ (58,564)	$ (16,536)
Adjustments to reconcile net loss to net cash provided by operating activities:
Accretion of asset retirement obligations	79	43
Depreciation, depletion and amortization	17,891	15,382
Stock-based compensation	533	450
Stock-based payments	0	(610)
Deferred taxes	(12,922)	(3,191)
Loss on derivative financial instruments	36,238	11,156
Settlements of derivative financial instruments	1,309	(3,116)
Gain on disposal of property and equipment	(17)	0
Loss on abandoned property and equipment	0	170
Loss on sale of oil and gas properties	32,894	0
Non-cash interest expense	699	2,477
Change in fair value of warrants	102	152
Changes in operating assets and liabilities:
Accounts receivable	(2,016)	(131)
Prepaid expenses and other assets	304	(709)
Accounts payable and accrued expenses	(6,704)	4,310
Net cash provided by operating activities	9,826	9,847
Cash flows from investing activities
Acquisition of oil and gas properties	(2,352)	(1,605)
Development of oil and gas properties	(29,137)	(31,523)
Proceeds from sale of oil and gas properties	12,107	0
Purchases of other property and equipment	(2,916)	(1,348)
Net cash used in investing activities	(22,298)	(34,476)
Cash flows from financing activities
Proceeds from borrowings	30,000	264,565
Payments on borrowings	(19,116)	(240,436)
Net cash provided by financing activities	10,884	24,129
Net increase in cash and cash equivalents	(1,588)	(500)
Cash and cash equivalents, beginning of the period	5,355	2,538
Cash and cash equivalents, end of the period	3,767	2,038
Supplemental information:
Cash paid for taxes	0	1,147
Cash paid for interest	16,743	3,970
Non-cash investing and financing activities:
Change in asset retirement obligation	(522)	32
Change in liabilities for capital expenditures	$ 730	$ 406