Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net loss	$ (54,541,000)	$ (116,655,000)	$ (28,834,000)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation, depletion and amortization	25,937,000	31,228,000	18,414,000
Impairment of goodwill	17,532,000	1,547,000	0
Impairment of proved and unproved oil and gas properties	24,283,000	138,086,000	19,359,000
Total loss (gain) on derivative contracts, net	6,638,000	(6,431,000)	(4,392,000)
Operating portion of net cash received in settlement of derivative contracts	3,225,000	6,306,000	778,000
Rig idle and termination expense	5,059,000
Stock-based compensation	3,301,000
Accretion of asset retirement obligations	551,000	550,000	317,000
Deferred income taxes	528,000	(26,533,000)	22,105,000
Amortization of deferred financing costs	298,000	264,000	164,000
Settlement of asset retirement obligations	(15,000)	(108,000)	(56,000)
Gain on sale of oil and gas properties	(8,000)	(1,617,000)
Changes in assets and liabilities:
Decrease (increase) in accounts receivable	3,807,000	9,246,000	(5,305,000)
Decrease (increase) in prepaid expenses and other current assets	511,000	779,000	(194,000)
(Decrease) increase in accounts payable and accrued expenses	(9,151,000)	(30,887,000)	28,408,000
Increase (decrease) in revenues and royalties payable	2,194,000	(8,739,000)	7,099,000
(Decrease) increase in advances	(10,905,000)	(5,929,000)	17,925,000
Net cash provided by (used in) operating activities	1,712,000	(10,440,000)	75,788,000
Cash flows from investing activities:
Acquisition of oil and gas properties		(8,706,000)	(18,772,000)
Additions to oil and gas properties	(28,417,000)	(61,060,000)	(83,041,000)
Additions to office and other equipment	(117,000)	(378,000)	(1,385,000)
Proceeds from sale of oil and gas properties		3,441,000
Proceeds from sale of land		101,000
Net cash used in investing activities	(59,868,000)	(66,602,000)	(107,437,000)
Cash flows from financing activities:
Proceeds from borrowings	36,597,000		11,191,000
Repayments of borrowings	(38,549,000)		(10,825,000)
Deferred financing costs	(81,000)	(141,000)	(613,000)
Contributions, net of issuance costs			106,920,000
Issuance of common stock, net of offering costs of $2.7 million	47,125,000
Net cash provided by (used in) financing activities	45,092,000	(141,000)	106,673,000
Net (decrease) increase in cash and cash equivalents	(13,064,000)	(77,183,000)	75,024,000
Cash at beginning of period	23,264,000	100,447,000	25,423,000
Cash at end of period	10,200,000	23,264,000	100,447,000
Cash paid for:
Interest	961,000	415,000	493,000
Non-cash investing and financing activities:
Asset retirement obligations	152,000	150,000	237,000
Accruals of property, plant and equipment	2,374,000	7,665,000	18,219,000
Acquisition of oil and gas properties		1,991,000
Promissory Note	5,059,000
Lynden Arrangement [Member]
Cash flows from investing activities:
Business acquisition, net of cash acquired	(31,334,000)
Non-cash investing and financing activities:
Common stock issued	45,699,000
Oak Valley Resources, LLC [Member]
Cash flows from investing activities:
Business acquisition, net of cash acquired			(4,239,000)
2014 Eagle Ford Acquisition [Member]
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Impairment of goodwill		1,500,000
Non-cash investing and financing activities:
Common stock issued			56,425,000
Proved And Unproved Property [Member]
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Impairment of proved and unproved oil and gas properties	$ 6,751,000	$ 136,539,000	$ 19,359,000