CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 7,354	$ 17,660
Restricted cash - other	1,981	1,985
Accounts receivable, net	51,053	45,503
Derivative contracts	0	5,286
Prepaid expenses	3,128	2,628
Other current assets	251	265
Total current assets	63,767	73,327
Oil and natural gas properties, using full cost method of accounting
Proved	1,344,552	1,269,091
Unproved	57,363	60,152
Less: accumulated depreciation, depletion and impairment	(614,972)	(580,132)
Net oil and natural gas properties capitalized costs	786,943	749,111
Other property, plant and equipment, net	200,014	200,838
Other assets	820	1,062
Total assets	1,051,544	1,024,338
Current liabilities
Accounts payable and accrued expenses	119,436	111,797
Current maturities of long-term debt	20,000	0
Asset retirement obligation	25,355	25,393
Other current liabilities	29	0
Total current liabilities	164,820	137,190
Asset retirement obligation	35,836	34,671
Other long-term obligations	7,428	4,756
Total liabilities	208,084	176,617
Commitments and contingencies (Note 9)
Stockholders’ Equity
Common stock, $0.001 par value; 250,000 shares authorized; 35,687 issued and outstanding at March 31, 2019 and December 31, 2018	36	36
Warrants	88,518	88,516
Additional paid-in capital	1,056,235	1,055,164
Accumulated deficit	(301,329)	(295,995)
Total stockholders’ equity	843,460	847,721
Total liabilities and stockholders’ equity	$ 1,051,544	$ 1,024,338

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130549-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682