Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating Activities:
Net income	$ 225	$ 20,885
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sale of non-oil and gas assets	(12)	(102)
Net loss (gain) on derivative contracts	27,646	(15,831)
Derivative contract settlements	(9,847)	2,000
Depreciation, depletion and amortization	18,835	9,789
Amortization of deferred financing fees	207	254
Accretion expense and other	264	224
Stock-based compensation	1,466	1,749
Changes in operating assets and liabilities:
Accounts receivable	(631)	1,895
Other assets	1,381	(1,041)
Accounts payable and accrued expenses	5,752	(6,875)
Net cash provided by operating activities	45,286	12,947
Investing Activities
Capital expenditures, including purchase and development of properties	(73,818)	(25,002)
Proceeds from the sale of oil and gas properties	82	10,653
Proceeds from the sale of non-oil and gas assets	27	204
Net cash used in investing activities	(73,709)	(14,145)
Financing Activities
Proceeds from long-term borrowings	35,000	20,000
Payments of long-term borrowings	(7,129)	(82,659)
Exercise of stock options	15
Proceeds from issuance of common stock		65,223
Deferred financing fees	(199)	(714)
Net cash provided by financing activities	27,687	1,850
(Decrease) increase in cash and cash equivalents	(736)	652
Cash and cash equivalents at beginning of period	1,618
Cash and cash equivalents at end of period	882	652
Supplemental disclosure of cash flow information:
Interest paid	2,577	802
Non-cash investing and financing activities
Change in capital expenditures included in accounts payable	2,267	15,451
Increase in asset retirement obligation in capital expenditures	36
	$ 2,303	$ 15,451