Zion Oil & Gas (ZNOG) 10-Q 14 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 09, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	ZION OIL & GAS INC
Entity Central Index Key	0001131312
Trading Symbol	ZN
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Ex Transition Period	false
Entity Common Stock Shares Outstanding		72,982,303

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 2,024	$ 2,791
Fixed short term bank deposits - restricted	1,100	1,325
Prepaid expenses and other	420	461
Other deposits	150	280
Governmental receivables	6	361
Other receivables	139	153
Total current assets	3,839	5,371
Unproved oil and gas properties, full cost method (see Note 4)	6,900	6,714
Property and equipment at cost
Net of accumulated depreciation of $468 and $455	146	156
Right of Use Lease Assets (see Note 7)	730
Other assets
Fixed short term bank deposits - restricted	11	9
Assets held for severance benefits	288	271
Total other assets	299	280
Total assets	11,914	12,521
Current liabilities
Accounts payable	699	2,811
Lease obligation - current (see Note 7)	210
Asset retirement obligation	696	720
Derivative liability (see Note 6)	723	345
Accrued liabilities	852	958
Total current liabilities	3,180	4,834
Long-term liabilities
10% Senior convertible bonds, net of unamortized deferred financing cost of $57 and $63 and unamortized debt discount of $900 and $993 at March 31, 2019 and December 31, 2018 respectively (see Note 5)	2,309	2,211
Lease obligation - non-current (see Note 7)	564
Obligation under capital lease, net of current maturities of $10	27	30
Provision for severance pay	331	317
Total long-term liabilities	3,231	2,558
Total liabilities	6,411	7,392
Commitments and contingencies (see Note 8)
Stockholders' equity
Common stock, par value $.01; Authorized: 200,000,000 shares at March 31, 2019: Issued and outstanding: 71,065,742 and 66,405,180 shares at March 31, 2019 and December 31, 2018 respectively	711	664
Additional paid-in capital	206,077	203,580
Accumulated deficit	(201,285)	(199,115)
Total stockholders' equity	5,503	5,129
Total liabilities and stockholders' equity	$ 11,914	$ 12,521

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Balance Sheets [Abstract]
Property and equipment, accumulated depreciation	$ 468	$ 455
Unamortized deferred financing cost, net	57	63
Unamortized debt discount	900	993
Obligation under capital lease of current maturities	$ 10	$ 10
Common stock, par value	$ 0.01	$ 0.01
Common stock, authorized	200,000,000	200,000,000
Common stock, issued	71,065,742	66,405,180
Common stock, outstanding	71,065,742	66,405,180

Condensed Statements of Operati

Condensed Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statements of Operations [Abstract]
General and administrative	$ 926	$ 1,959
Impairment of unproved oil and gas properties	163
Other	555	553
Loss from operations	(1,644)	(2,512)
Other income (expense), net
(Loss) on derivative liability	(378)	(3,534)
Foreign exchange (loss) gain	6	(32)
Financial (expenses), net	(154)	(173)
Loss before income taxes	(2,170)	(6,251)
Income taxes
Net loss	$ (2,170)	$ (6,251)
Net loss per share of common stock - basic and diluted (in US$)	$ (0.03)	$ (0.11)
Weighted-average shares outstanding-basic and diluted (in thousands)	69,987	57,504

Condensed Statement of Changes

Condensed Statement of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands		Total		Common Stock		Additional paid-in Capital		Accumulated deficit
Beginning Balances at Dec. 31, 2017		$ 24,440		$ 559		$ 184,485		$ (160,604)
Beginning Balances (in shares) at Dec. 31, 2017				55,888
Funds received from sale of DSPP units and shares		3,835		$ 14		3,821
Funds received from sale of DSPP units and shares (in shares)				1,420
Value of bonds converted to shares		148			[1]	148
Value of bonds converted to shares (in shares)				32
Funds received from option exercises	[1]
Funds received from option exercises (in shares)				5
Value of options granted to employees, directors and others as non-cash compensation		1,245				1,245
Net loss		(6,251)						(6,251)
Ending Balances at Mar. 31, 2018		23,417		$ 573
Ending Balances (in shares) at Mar. 31, 2018				57,345
Beginning Balances at Dec. 31, 2018		5,129		$ 664		203,580		(199,115)
Beginning Balances (in shares) at Dec. 31, 2018				66,405
Funds received from sale of DSPP units and shares		2,528		$ 46		2,482
Funds received from sale of DSPP units and shares (in shares)				4,608
Value of bonds converted to shares			[1]		[1]		[1]
Value of bonds converted to shares (in shares)	[1]
Funds received from option exercises		1		$ 1
Funds received from option exercises (in shares)				53
Value of options granted to employees, directors and others as non-cash compensation		15				15
Net loss		(2,170)						(2,170)
Ending Balances at Mar. 31, 2019		$ 5,503		$ 711		$ 206,077		$ (201,285)
Ending Balances (in shares) at Mar. 31, 2019				71,066
[1]	Less than one thousand.

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019		Mar. 31, 2018
Cash flows from operating activities
Net loss	$ (2,170)		$ (6,251)
Adjustments required to reconcile net loss to net cash used in operating activities:
Depreciation	12		14
Capital gain on sale of property and equipment
Cost of options issued to employees, directors and others as non-cash compensation	15		948
Amortization of debt discount related to convertible bonds	169		161
Change in derivative liability	378		3,534
Impairment of unproved oil and gas properties	163
Change in assets and liabilities, net:
Other deposits	130		7
Prepaid expenses and other	41		2
Governmental receivables	355		675
Lease obligation - current	210
Lease obligation - non current	564
Right of Use Lease Assets	(730)
Other receivables	14		(21)
Severance pay	(3)		(2)
Accounts payable	(28)		(108)
Asset retirement obligation	(24)
Accrued liabilities	(162)		50
Net cash used in operating activities	(1,066)		(991)
Cash flows from investing activities
Acquisition of property and equipment	(2)		(8)
Investment in unproved oil and gas properties	(2,448)		(5,489)
Net cash used in investing activities	(2,450)		(5,497)
Cash flows from financing activities
Payments related to capital lease	(3)		(2)
Proceeds from exercise of stock options	1
Deferred offering costs			(79)
Proceeds from issuance of stock and exercise of warrants	2,528		3,835
Net cash provided by financing activities	2,526		3,754
Net (decrease), increase in cash, cash equivalents and restricted cash	(990)		(2,734)
Cash, cash equivalents and restricted cash - beginning of period	4,125		9,079
Cash, cash equivalents and restricted cash - end of period	3,135		6,345
Non-cash investing and financing activities:
Cost of options capitalized to oil & gas properties			297
Unpaid investments in oil & gas properties	587		1,998
Convertible Bond interest paid in shares
10% Senior Convertible Bonds converted to shares		[1]	148
Acquisition of property and equipment under capital lease
Capitalized convertible bond interest attributed to oil and gas properties	$ 10		$ 86
[1]	Less than one thousand

Condensed Statements of Cash _2

Condensed Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statements Of Cash Flows [Abstract]
Cash and cash equivalents	$ 2,024	$ 2,791
Restricted cash included in fixed short-term bank deposits	11	1,325
Restricted cash included in fixed long-term bank deposits	1,100	9
Cash, cash equivalents and restricted cash	$ 3,135	$ 4,125

Nature of Operations, Basis of

Nature of Operations, Basis of Presentation and Going Concern	3 Months Ended
	Mar. 31, 2019
Nature of Operations, Basis of Presentation and Going Concern [Abstract]
Nature of Operations, Basis of Presentation and Going Concern	Note 1 - Nature of Operations, Basis of Presentation and Going Concern A. Nature of Operations Zion Oil & Gas, Inc., a Delaware corporation (“we,” “our,” “Zion” or the “Company”) is an oil and gas exploration company with a history of 19 years of oil & gas exploration in Israel. As of March 31, 2019, the Company has no revenues from its oil and gas operations. Zion maintains its corporate headquarters in Dallas, Texas. We also have branch offices in Caesarea, Israel and Geneva, Switzerland. The purpose of the Israel branch is to support the Company’s operations in Israel, and the purpose of the Switzerland branch is to operate a foreign treasury center for the Company. Exploration Rights/Exploration Activities The Company currently holds one active petroleum exploration license onshore Israel, the Megiddo-Jezreel License, comprising approximately 99,000 acres. The Megiddo Jezreel #1 (“MJ #1”) exploratory well was spud on June 5, 2017 and drilled to a total depth (“TD”) of 5,060 meters (approximately 16,600 feet). Thereafter, the Company successfully cased and cemented the well while awaiting the approval of the testing protocol. The Ministry of Energy approved the well testing protocol on April 29, 2018. During the fourth quarter of 2018, the Company’s testing protocol was concluded at the MJ #1 well. The test results confirmed that the MJ #1 well did not contain hydrocarbons in commercial quantities in the zones tested. As a result of the above determination, in the year ended December 31, 2018, the Company recorded a non-cash impairment charge to its unproved oil and gas properties of $30,906,000. During the first quarter of 2019, the Company recorded a post-impairment charge of approximately $163,000. The MJ#1 well provided Zion with information Zion believes is important for potential future exploration efforts within its license area. As with many frontier wildcat wells, the MJ#1 also left several questions unanswered. While not meant to be an exhaustive list, a summary of what Zion believes to be key information learned in the MJ#1 well is as follows: 1. The MJ#1 encountered much higher subsurface temperatures at a depth shallower than expected before drilling the well. In our opinion, this is significant because reaching a minimum temperature threshold is necessary for the generation of hydrocarbons from an organic-rich source rock. 2. The known organic rich (potentially hydrocarbon bearing) Senonian age source rocks that are typically present in this part of Israel were not encountered as expected. Zion expected these source rocks to be encountered at approximately 1,000 meters in the MJ#1 well. 3. MJ#1 had natural fractures, permeability (the ability of fluid to move through the rock) and porosity (pore space in rock) that allowed the sustained flow of formation fluid in the shallower Jurassic and lower Cretaceous age formations between approximately 1,200 and 1,800 meters. While no hydrocarbons were encountered, Zion believes this fact is nonetheless significant because it provides important information about possible reservoir pressures and the ability of fluids to move within the formation and to the surface. 4. MJ#1 encountered oil in the Triassic Mohilla formation which Zion believes suggests an active deep petroleum system is in Zion’s license area. There was no natural permeability or porosity in the Triassic Mohilla formation to allow formation fluid to reach the surface naturally during testing and thus the MJ#1 was not producible or commercial. 5. The depths and thickness of the formations we encountered varied greatly from pre-drill estimates. This required the MJ#1 to be drilled to a much greater depth than previously expected. Zion has tied these revised formation depths to seismic data which will allow for more accurate interpretation and mapping in the future. A summary of what Zion believes to be some key questions left to be answered are: 1. Is the missing shallow Senonian age source rock a result of regional erosion, or is it missing because of a fault that cut the well-bore and could be reasonably expected to be encountered in the vicinity of the MJ#1 drill site? Zion believes this is an important question to answer because if the Senonian source rocks do exist in this area, the high temperatures encountered are sufficient to mature these source rocks and generate oil. 2. Do the unusually high shallow subsurface temperatures extend regionally beyond the MJ#1 well, which could allow for the generation of hydrocarbons in the Senonian age source rock within our license area? 3. As a consequence of seismic remapping, where does the MJ#1 well lie relative to the potential traps at the Jurassic and Triassic levels and was the well location too low on the structures and deeper than the potential hydrocarbons within those traps? As a result of these unanswered questions and with the information gained drilling the MJ#1 well, Zion now believes it is prudent and consistent with good industry practice to try and answer some of these questions with a focused 3D seismic imaging shoot of approximately 60 square kilometers surrounding the MJ#1 well. Zion received a multi-year license extension through December 2, 2020. The Company has completed preliminary field scouting and a suggested final survey design for the proposed 3D seismic survey. The permitting process has begun, as well as identifying potential seismic source equipment and wireless geophones to record the signal, which Zion believes it might be necessary to import. Contracts with seismic services providers will need to be negotiated along with potential surface damages to crops, irrigation piping and other surface features. Once data acquisition is completed, interpretation is the final step and will involve integration with, and modification of, previous work by Zion technical staff. Zion’s ability to fully undertake all of these aforementioned activities is subject to its raising the needed capital from its continuing offerings, of which no assurance can be provided. Megiddo-Jezreel Petroleum License, No. 401 (“MJL”) The MJL was awarded on December 3, 2013 for a three-year primary term through December 2, 2016, with the possibility of additional one-year extensions up to a maximum of seven years. The MJL lies onshore, south and west of the Sea of Galilee, and the Company continues its exploration focus here as it appears to possess the key geologic ingredients of an active petroleum system with significant exploration potential. In late November 2016, The State of Israel’s Petroleum Commissioner officially approved Zion’s drilling date and license extension request. On October 30, 2017, the Company sought a multi-year extension to its existing license. After receiving feedback from Israel’s Petroleum Commissioner, the Company submitted a revised extension request on November 9, 2017. On November 20, 2017, Israel’s Petroleum Commissioner officially approved the Company’s multi-year extension request on its Megiddo-Jezreel License No. 401, extending its validity to December 2, 2019. Until recently, the Company remained subject to the following updated key license terms: No. Activity Description Execution by: 1 Submit final report on the results of drilling 31 May 2018 2 Submit program for continuation of work under license 30 June 2018 On June 1, 2018, Zion submitted its Megiddo-Jezreel #1 End of Well Report (EOWR) On June 14, 2018 Zion submitted its Application for Extension of Continued Work Program Due Date on the Megiddo-Jezreel License No. 401 No. Activity Description Execution by: 1 Submit program for continuation of work under license 1 November 2018 On October 16, 2018 Zion submitted its Application for Extension of Continued Work Program Due Date on the Megiddo-Jezreel License No. 401 No. Activity Description Execution by: 1 Submit program for continuation of work under license 31 January 2019 On January 31, 2019, Zion submitted its Application for Extension of Continued Work Program Due Date on the Megiddo-Jezreel License No. 401 Number Activity Description Execution by: 3 Submit program for continuation of work under license 28 February 2019 The continuation of work program was timely submitted to Israel’s Petroleum Commissioner and subsequently approved. Number Activity Description 1 Received approval for an extension of the MJ#1 License through December 2, 2020 28 February 2019 On February 24, 2019 and thereafter on February 26, 2019 Zion submitted its proposed 2019 WORK PROGRAM ON the Megiddo-Jezreel License No. 401. On February 28, 2019 Israel’s Petroleum Commissioner officially approved the revised and updated Work Program on the Megiddo-Jezreel License No. 401 as shown below : Number Activity description Execution by: 1 Submission of seismic survey plan to the Commissioner and execution of an agreement with a contractor to perform 30 April 2019 2 Commence 3D seismic survey in an area of approximately 50 square kilometers 1 August 2019 3 Transfer of field material configuration and processed material to the Ministry pursuant to Ministry guidelines 15 December 2019 4 Submit interpretation report 20 February 2020 On February 24, 2019 Zion submitted a request to the Commissioner to extend the Megiddo-Jezreel License No. 401 up to December 2, 2020. On February 28, 2019 the Commissioner approved the extension of the Megiddo-Jezreel License No. 401 up to December 2, 2020. On April 30, 2019 Zion submitted its Application for Extension of Continued Work Program Due Date on the Megiddo-Jezreel License No. 401 Zion’s proposed new timelines and activity descriptions are shown below: Number Activity description Execution by: 1 Submission of seismic survey plan to the Commissioner and execution of an agreement with a contractor to perform 30 November, 2019 2 Commence 3D seismic survey in an area of approximately 60 square kilometers 1 April, 2020 3 Transfer of field material configuration and processed material to the Ministry pursuant to Ministry guidelines 15 August 2020 4 Submit interpretation report 15 November, 2020 On May 1, 2019, Israel’s Petroleum Commissioner granted Zion’s work program report extension to November 1, 2019, as shown below. As previously disclosed, the Company required authorization from the Israel Land Authority (the “ILA”), the formal lessor of the land to Kibbutz Sde Eliyahu, on whose property the drilling pad is currently situated, to access and utilize the drill site (“surface use agreement”). The Company received this authorization on July 4, 2016. This was preceded by the Company’s May 15, 2016 signed agreement with the kibbutz. On January 11, 2017, an agreement was signed by the Company and the ILA by which the surface usage agreement was extended through December 3, 2017. On December 31, 2017, an agreement was signed by the Company and the ILA by which the surface usage agreement was extended through December 3, 2019. Zion’s Former Jordan Valley, Joseph, and Asher-Menashe Licenses On March 29, 2015, the Energy Ministry formally approved the Company’s application to merge the southernmost portion of the Jordan Valley License into the Megiddo-Jezreel License. The Company has plugged all of its exploratory wells (in the former Joseph and Asher-Menashe Licenses) but acknowledges its obligation to complete the abandonment of these well sites in accordance with guidance from the Environmental Ministry and local officials. B. Basis of Presentation The accompanying unaudited interim condensed financial statements of Zion Oil & Gas, Inc. have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and with Article 8-03 of Regulation S-X. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, all adjustments, consisting only of normal recurring accruals necessary for a fair statement of financial position, results of operations and cash flows, have been included. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the financial statements and the accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018. The year-end balance sheet data presented for comparative purposes was derived from audited financial statements, but does not include all disclosures required by GAAP. The results of operations for the three months ended March 31, 2019 are not necessarily indicative of the operating results for the year ending December 31, 2019 or for any other subsequent interim period. C. Going Concern The Company incurs cash outflows from operations, and all exploration activities and overhead expenses to date have been financed by way of equity or debt financing. The recoverability of the costs incurred to date is uncertain and dependent upon achieving significant commercial production. The Company’s ability to continue as a going concern is dependent upon obtaining the necessary financing to undertake further exploration and development activities and ultimately generating profitable operations from its oil and natural gas interests in the future. The Company’s current operations are dependent upon the adequacy of its current assets to meet its current expenditure requirements and the accuracy of management’s estimates of those requirements. Should those estimates be materially incorrect, the Company’s ability to continue as a going concern may be impaired. The financial statements have been prepared on a going concern basis, which contemplates realization of assets and liquidation of liabilities in the ordinary course of business. During the three months ended March 31, 2019, the Company incurred a net loss of approximately $2.2 million and had an accumulated deficit of approximately $201 million. These factors raise substantial doubt about the Company’s ability to continue as a going concern. To carry out planned operations, the Company must raise additional funds through additional equity and/or debt issuances or through profitable operations. There can be no assurance that this capital or positive operational income will be available to the Company, and if it is not, the Company may be forced to curtail or cease exploration and development activities. The financial statements do not include any adjustments that might result from the outcome of this uncertainty.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Summary of Significant Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2 - Summary of Significant Accounting Policies A. Net Gain (Loss) per Share Data Basic and diluted net (loss) gain per share of common stock, par value $0.01 per share (“Common Stock”), is presented in conformity with ASC 260-10 “Earnings Per Share.” Diluted net loss per share is the same as basic net loss per share, as the inclusion of 9,651,835 and 9,651,569 Common Stock equivalents in the three-month period ended March 31, 2019 and 2018 respectively, would be anti-dilutive. B. Use of Estimates The preparation of the accompanying financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities, and reported amounts of revenues and expenses. Such estimates include the valuation of unproved oil and gas properties, deferred tax assets, asset retirement obligations and legal contingencies. These estimates and assumptions are based on management’s best estimates and judgment. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, which management believes to be reasonable under the circumstances. The Company adjusts such estimates and assumptions when facts and circumstances dictate. Illiquid credit markets, volatile equity, foreign currency, and energy markets have combined to increase the uncertainty inherent in such estimates and assumptions. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in those estimates resulting from continuing changes in the economic environment will be reflected in the financial statements in future periods. C. Oil and Gas Properties and Impairment The Company follows the full-cost method of accounting for oil and gas properties. Accordingly, all costs associated with acquisition, exploration and development of oil and gas reserves, including directly related overhead costs, are capitalized. All capitalized costs of oil and gas properties, including the estimated future costs to develop proved reserves, are amortized on the unit-of-production method using estimates of proved reserves. Investments in unproved properties and major development projects are not amortized until proved reserves associated with the projects can be determined or until impairment occurs. If the results of an assessment indicate that the properties are impaired, the amount of the impairment is included in loss from continuing operations before income taxes, and the adjusted carrying amount of the proved properties is amortized on the unit-of-production method. The Company’s oil and gas property represents an investment in unproved properties. These costs are excluded from the amortized cost pool until proved reserves are found or until it is determined that the costs are impaired. All costs excluded are reviewed at least quarterly to determine if impairment has occurred. The amount of any impairment is charged to expense since a reserve base has not yet been established. Impairment requiring a charge to expense may be indicated through evaluation of drilling results, relinquishing drilling rights or other information. During the fourth quarter of 2018, the Company testing protocol was concluded at the Megiddo Jezreel #1 (“MJ #1”) well. The test results confirmed that the MJ #1 well did not contain hydrocarbons in commercial quantities in the zones tested. As a result of the above determination, in the year ended December 31, 2018, the Company recorded a non-cash impairment charge to its unproved oil and gas properties of $30,906,000 (see Note 4). During the first quarter of 2019, the Company recorded a post-impairment charge of approximately $163,000. Currently, the Company has no economically recoverable reserves and no amortization base. The Company’s unproved oil and gas properties consist of capitalized exploration costs of $6,900,000 and $6,714,000 as of March 31, 2019, and December 31, 2018, respectively. D. Fair Value Measurements The Company follows Accounting Standards Codification (ASC) 820, “Fair Value Measurements and Disclosures,” as amended by Financial Accounting Standards Board (FASB) Financial Staff Position (FSP) No. 157 and related guidance. Those provisions relate to the Company’s financial assets and liabilities carried at fair value and the fair value disclosures related to financial assets and liabilities. ASC 820 defines fair value, expands related disclosure requirements, and specifies a hierarchy of valuation techniques based on the nature of the inputs used to develop the fair value measures. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date, assuming the transaction occurs in the principal or most advantageous market for that asset or liability. There are three levels of inputs to fair value measurements - Level 1, meaning the use of quoted prices for identical instruments in active markets; Level 2, meaning the use of quoted prices for similar instruments in active markets or quoted prices for identical or similar instruments in markets that are not active or are directly or indirectly observable; and Level 3, meaning the use of unobservable inputs. The Company uses Level 1 inputs for its fair value measurements whenever there is an active market, with actual quotes, market prices, and observable inputs on the measurement date. The Company uses Level 2 inputs for fair value measurements whenever there are quoted prices for similar securities in an active market or quoted prices for identical securities in an inactive market. The Company uses Level 3 inputs in the Binomial Model used for the valuation of the derivative liability. E. Derivative Liabilities In accordance with ASC 815-40-25 and ASC 815-10-15 Derivatives and Hedging and ASC 480-10-25 Liabilities-Distinguishing Liabilities from Equity, the embedded derivatives associated with the Convertible Bonds are accounted for as a liability during the term of the related Convertible Bonds (see Note 6). F. Stock-Based Compensation ASC 718, “Compensation – Stock Compensation,” prescribes accounting and reporting standards for all share-based payment transactions in which employee services are acquired. Transactions include incurring liabilities, or issuing or offering to issue shares, options, and other equity instruments such as employee stock ownership plans and stock appreciation rights. Share-based payments to employees, including grants of employee stock options, are recognized as compensation expense in the financial statements based on their fair values. That expense is recognized over the period during which an employee is required to provide services in exchange for the award, known as the requisite service period (usually the vesting period). The Company accounts for stock-based compensation issued to non-employees and consultants in accordance with the provisions of ASC 505-50, “Equity – Based Payments to Non-Employees.” Measurement of share-based payment transactions with non-employees is based on the fair value of whichever is more reliably measurable: (a) the goods or services received; or (b) the equity instruments issued. The fair value of the share-based payment transaction is determined at the earlier of performance commitment date or performance completion date. G. Related parties Parties are considered to be related to the Company if the parties, directly or indirectly, through one or more intermediaries, control, are controlled by, or are under common control with the Company. Related parties also include principal owners of the Company, its management, members of the immediate families of principal owners of the Company and its management and other parties with which the Company may deal if one party controls or can significantly influence the management or operating policies of the other to an extent that one of the transacting parties might be prevented from fully pursuing its own separate interests. All transactions with related parties are recorded at fair value of the goods or services exchanged. H. Recently Adopted Accounting Pronouncements ASU 2016-02 and ASU 2018-01 – Leases (Topic 842) In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-02, Leases (Topic 842) (“ASU 2016-02”) in order to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet for those leases classified as operating leases under previous GAAP. ASU 2016-02 requires that a lessee should recognize a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term on the balance sheet. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 (including interim periods within those periods) using a modified retrospective approach and early adoption is permitted. Zion adopted ASU 2016-02 in the first quarter of 2019. Presently, Zion has operating leases for office space in Dallas, Texas and in Caesarea, Israel plus various leases for motor vehicles. These leases have been accounted for under ASU 2016-02 in 2019 by establishing a right-of-use asset and a corresponding current lease liability and non-current lease liability. Zion is not subject to any loan covenants and therefore, the increase in assets and liabilities does not have a material impact on its business. In January 2018, the FASB issued ASU 2018-01, “Land Easement Practical Expedient for Transition to “Topic 842.” The amendments in this Update provide an optional transition practical expedient to not evaluate under Topic 842 existing or expired land easements that were not previously accounted for as leases under Topic 840, Leases. An entity that elects this practical expedient should evaluate new or modified land easements under Topic 842 beginning at the date that the entity adopts Topic 842. An entity that does not elect this practical expedient should evaluate all existing or expired land easements in connection with the adoption of the new lease requirements in Topic 842 to assess whether they meet the definition of a lease. The Company does not have any land easements and believes that this ASU 2018-01 has no effect on the Company. ASU 2016-15 and ASU 2016-08 – Statement of Cash Flows (Topic 230) In August 2016, the FASB issued AS 2016-15, “Classification of Certain Cash Receipts and Cash Payments”, which clarifies how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The effective date for ASU 2016-15 is for fiscal years beginning after December 15, 2018, and interim periods within fiscal years beginning after December 15, 2019. Early adoption is permitted. The Company is currently evaluating the impact of adopting ASU 2016-15 on our financial statements. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230) (“ASU 2016-18”), which requires that restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total cash amounts shown on the statement of cash flows. The effective date for ASU 2016-18 is for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. We adopted ASU 2016-18 effective January 1, 2018. The adoption of ASU 2016-18 had no impact on our retained earnings, and no impact to our net income on an ongoing basis. Adoption of the new standard requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents and amounts generally described as restricted cash, or restricted cash equivalents. The amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statements of cash flows. The amendments have been applied using a retrospective transition method to each period presented, as required. The period ended March 31, 2019 has been reclassified to reflect this change. In March 2018, the FASB issued ASU 2018-05, “Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118”. This ASU expresses the view of the staff regarding application of Topic 740, Income Taxes, in the reporting period that includes December 22, 2017, the date on which the Tax Cuts and Jobs Act (H.R.1, An Act to Provide for Reconciliation Pursuant to Titles II and V of the Concurrent Resolution on the Budget for Fiscal Year 2018) was signed into law. The Company is currently evaluating the impact of adopting ASU 2018-05 on our financial statements. ASU 2016-09 In March 2016, the FASB issued ASU No. 2016-09, Compensation – Stock Compensation, or ASU No. 2016-09. The areas for simplification in this Update involve several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. For public entities, the amendments in this Update are effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted in any interim or annual period. If an entity early adopts the amendments in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes that interim period. An entity that elects early adoption must adopt all of the amendments in the same period. Amendments related to the timing of when excess tax benefits are recognized, minimum statutory withholding requirements, forfeitures, and intrinsic value should be applied using a modified retrospective transition method by means of a cumulative-effect adjustment to equity as of the beginning of the period in which the guidance is adopted. Amendments related to the presentation of employee taxes paid on the statement of cash flows when an employer withholds shares to meet the minimum statutory withholding requirement should be applied retrospectively. Amendments requiring recognition of excess tax benefits and tax deficiencies in the income statement and the practical expedient for estimating expected term should be applied prospectively. An entity may elect to apply the amendments related to the presentation of excess tax benefits on the statement of cash flows using either a prospective transition method or a retrospective transition method. The Company believes that this ASU No. 2016-09 has no impact on our financial statements. The Company does not believe that the adoption of any recently issued accounting pronouncements in 2019 had a significant impact on our financial position, results of operations, or cash flow, except for ASC Update No. 2015-03—Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, which requires debt issuance costs to be presented in the balance sheet as a direct deduction from the carrying value of the associated debt liability, consistent with the presentation of a debt discount. For public business entities, the amendments in this Update are effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. At March 31, 2019 and December 31, 2018, the Company reclassified $57,000 and $63,000, respectively, in deferred offering costs from an asset account and applied it to the outstanding debt balance (see Note 5).

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2019
Stockholders' Equity [Abstract]
Stockholders' Equity	Note 3 - Stockholders’ Equity A. 2011 Equity Incentive Stock Option Plan During the three months ended March 31, 2019, the Company granted the following options from the 2011 Equity Incentive Plan for employees, directors and consultants, to purchase as non-cash compensation (the exercise of penny stock options is taxable at full market value on the date of exercise): i. Options to purchase 25,000 shares of Common Stock to one senior officer at an exercise price of $0.01 per share. The options vested upon grant and are exercisable through January 6, 2029. The fair value of the options at the date of grant amounted to approximately $10,000. During the three months ended March 31, 2018, the Company granted the following options from the 2011 Equity Incentive Plan for employees, directors and consultants, to purchase as non-cash compensation (the exercise of penny stock options are taxable on the date of exercise): i. Options to purchase 330,000 shares of Common Stock to 23 senior officers, staff members and consultants at an exercise price of $.01 per share. The options have vesting schedules of 165,000 shares on June 30, 2018 and 165,000 shares on December 31, 2018. The options are exercisable through January 1, 2028. The fair value of the options at the date of grant amounted to approximately $759,000. ii. Options to purchase 110,000 shares of Common Stock to five senior officers at an exercise price of $0.01 per share. The options vested upon grant and are exercisable through January 4, 2028. The fair value of the options at the date of grant amounted to approximately $250,000. iii. Options to purchase 55,000 shares of Common Stock to three consultants an exercise price of $0.01 per share. The options vested upon grant. However, the exercisability of these options is according to the following schedule: (a) 27,500 options are exercisable on June 30, 2018 and (b) the remaining 27,500 options are exercisable on June 30, 2019. The fair value of the options at the date of grant amounted to $222,000. B. 2011 Non-Employee Directors Stock Option Plan During the three months ended March 31, 2019, the Company did not grant any qualified (market value) options from the 2011 Non-Employee Directors Stock Option Plan to its directors. During the three months ended March 31, 2018, the Company granted the following qualified (market value) options from the 2011 Non-Employee Directors Stock Option Plan for directors to purchase as non-cash compensation: i. Options to purchase 400,000 shares of Common Stock to eight board members at an exercise price of $2.31 per share. The options vested upon grant and are exercisable through January 1, 2024. The fair value of the options at the date of grant amounted to approximately $428,000. C. Stock Options The stock option transactions since January 1, 2019 are shown in the table below: Number of shares Weighted Average exercise price US$ Outstanding, December 31, 2018 4,788,443 1.37 Changes during 2019 to: Granted to employees, officers, directors and others * 25,000 0.01 Expired/Cancelled/Forfeited (330,693 ) 2.11 Exercised (52,500 ) 0.01 Outstanding, March 31, 2019 4,430,250 1.33 Exercisable, March 31, 2019 4,420,250 1.33 * The receipt of a stock option grant by the grantee recipient is a non-taxable event according to the Internal Revenue Service. The grantee who later chooses to exercise penny stock options must recognize the market value in income in the year of exercise. The following table summarizes information about stock options outstanding as of March 31, 2019: Shares underlying outstanding options (non-vested) Shares underlying outstanding options (fully vested) Range of exercise price Number outstanding Weighted average remaining contractual life (years) Weighted Average Exercise price Range of exercise price Number Outstanding Weighted average remaining contractual life (years) Weighted Average Exercise price US$ US$ US$ US$ — — — — 0.01 15,000 4.62 0.01 — — — — 0.01 15,000 5.00 0.01 — — — — 0.01 5,000 5.20 0.01 — — — — 0.01 10,000 6.50 0.01 — — — — 0.01 25,000 6.75 0.01 — — — — 0.01 305,000 7.18 0.01 — — — — 0.01 525,000 7.75 0.01 — — — — 0.01 10,000 7.76 0.01 — — — — 0.01 60,000 8.04 0.01 0.01 10,000 8.75 0.01 0.01 30,000 8.50 0.01 — — — — 0.01 180,000 8.75 0.01 — — — — 0.01 85,000 8.76 0.01 — — — — 0.01 *45,000 8.91 0.01 — — — — 0.01 6,000 9.01 0.01 — — — — 0.01 25,000 9.77 0.01 — — — — 1.33 25,000 4.08 1.33 — — — — 1.38 108,000 1.76 1.38 — — — — 1.38 113,057 5.76 1.38 — — — — 1.55 400,000 3.18 1.55 — — — — 1.67 340,000 1.51 1.67 — — — — 1.67 428,193 5.51 1.67 — — — — 1.70 233,500 3.73 1.70 — — — — 1.75 400,000 4.27 1.75 — — — — 1.78 25,000 5.44 1.78 — — — — 1.87 25,000 2.84 1.87 — — — — 1.95 25,000 1.01 1.95 — — — — 1.96 25,000 0.43 1.96 — — — — 2.03 25,000 2.09 2.03 — — — — 2.31 400,000 4.76 2.31 2.61 481,500 2.68 2.61 — — — — 4.15 25,000 5.26 4.15 0.01 10,000 0.01 0.01-4.15 4,420,250 1.32 * 27,500 are exercisable on June 30, 2019. Granted to employees The following table sets forth information about the weighted-average fair value of options granted to employees and directors during the year, using the Black Scholes option-pricing model and the weighted-average assumptions used for such grants: For the three months ended March 31, 2019 2018 Weighted-average fair value of underlying stock at grant date $ 0.42 $ 2.31 Dividend yields — — Expected volatility 87 % 68%-70 % Risk-free interest rates 2.53 % 2.01%-2.25 % Expected lives (in years) 5.00 3.50-5.50 Weighted-average grant date fair value $ 0.41 $ 1.69 Granted to non-employees The following table sets forth information about the weighted-average fair value of options granted to non-employees during the year, using the Black Scholes option-pricing model and the weighted-average assumptions used for such grants: For the three months ended March 31, 2019 2018 Weighted-average fair value of underlying stock at grant date $ — $ 3.37 Dividend yields — — Expected volatility — 73%-76 % Risk-free interest rates — 2.46%-2.81 % Expected lives (in years) — 10.00 Weighted-average grant date fair value $ — $ 3.36 The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the options. The expected life represents the weighted average period of time that options granted are expected to be outstanding. The expected life of the options granted to employees and directors is calculated based on the Simplified Method as allowed under Staff Accounting Bulletin No. 110 (“SAB 110”), giving consideration to the contractual term of the options and their vesting schedules, as the Company does not have sufficient historical exercise data at this time. The expected life of the option granted to non-employees equals their contractual term. In the case of an extension of the option life, the calculation was made on the basis of the extended life. D. Compensation Cost for Warrant and Option Issuances The following table sets forth information about the compensation cost of warrant and option issuances recognized for employees and directors: For the three months ended March 31, 2019 2018 US$ thousands US$ thousands 15 943 The following table sets forth information about the compensation cost of warrant and option issuances recognized for non-employees: For the three months ended March 31, 2019 2018 US$ thousands US$ thousands — 302 The following table sets forth information about the compensation cost of option issuances recognized for employees and non-employees and capitalized to Unproved Oil & Gas properties: For the three months ended March 31, 2019 2018 US$ thousands US$ thousands — 297 As of March 31, 2019, there was approximately $5,000 of unrecognized compensation cost, related to non-vested stock options granted under the Company’s various stock option plans. The cost is expected to be recognized during the year 2019. E. Dividend Reinvestment and Stock Purchase Plan (“DSPP”) On March 27, 2014, the Company launched its Dividend Reinvestment and Stock Purchase Plan (the “DSPP”) pursuant to which stockholders and interested investors can purchase shares of the Company’s Common Stock as well as units of the Company’s securities directly from the Company. The terms of the DSPP are described in the Prospectus Supplement originally filed on March 31, 2014 (the “Original Prospectus Supplement”) with the Securities and Exchange Commission (“SEC”) under the Company’s effective registration Statement on Form S-3, as thereafter amended. On January 13, 2015, the Company amended the Original Prospectus Supplement (“Amendment No. 3”) to provide for a unit option (the “Unit Option”) under the DSPP comprised of one share of Common Stock and three Common Stock purchase warrants with each unit priced at $4.00. Each warrant afforded the participant the opportunity to purchase the Company’s Common Stock at a warrant exercise price of $1.00. Each of the three warrants series has different expiration dates that have been extended. The warrants became exercisable on May 2, 2016 and, in the case of ZNWAB continued to be exercisable through May 2, 2017 (1 year) and, in the case of ZNWAC continued to be exercisable through May 2, 2018 for ZNWAC (2 years) and May 2, 2019 for ZNWAD (3 years), respectively, at a per share exercise price of $1.00. As of May 2, 2017, any outstanding ZNWAB warrants expired. As of May 2, 2018, any outstanding ZNWAC warrants expired. On December 4, 2018, the Company extended the termination date of the ZNWAD Warrant by one (1) year from the expiration date of May 2, 2019 to May 2, 2020. On November 1, 2016, the Company launched a unit offering (the “Unit Program”) under the Company’s DSPP pursuant to which participants could purchase units comprised of seven shares of Common Stock and seven Common Stock purchase warrants, at a per unit purchase price of $10. The warrant is referred to as “ZNWAE.” The ZNWAE warrants became exercisable on May 1, 2017 and continue to be exercisable through May 1, 2020 at a per share exercise price of $1.00. The warrant terms provide that if the Company’s Common Stock trades above $5.00 per share at the closing price for 15 consecutive trading days at any time prior to the expiration date of the warrant, the Company may, in its sole discretion, accelerate the termination of the warrant upon providing 60 days advanced notice to the warrant holders. On February 23, 2017, the Company filed a Form S-3 with the SEC (Registration No. 333-216191) as a replacement for the Form S-3 (Registration No. 333-193336), for which the three year period ended March 31, 2017, along with the base Prospectus and Supplemental Prospectus. The Form S-3, as amended, and the new base Prospectus became effective on March 10, 2017, along with the Prospectus Supplement that was filed and became effective on March 10, 2017. The Prospectus Supplement under Registration No. 333-216191 describes the terms of the DSPP and replaces the prior Prospectus Supplement, as amended, under the prior Registration No. 333-193336. On May 22, 2017, the Company launched a new unit offering (the “New Unit Program”). The New Unit Program consisted of a new combination of common stock and warrants, a new time period in which to purchase under the program, and a new unit price, but otherwise the same unit program features, conditions and terms in the Prospectus Supplement applied. The New Unit Program terminated on July 12, 2017. This New Unit Program enabled participants to purchase Units of the Company’s securities where each Unit (priced at $250.00 each) was comprised of (i) the number of shares of Common Stock determined by dividing $250.00 (the price of one Unit) by the average of the high and low sale prices of the Company’s Common Stock as reported on the NASDAQ on the unit purchase date and (ii) Common Stock purchase warrants to purchase an additional 25 shares of Common Stock at a warrant exercise price of $1.00 per share. The warrant is referred to as “ZNWAF.” All ZNWAF warrants became exercisable on August 14, 2017 and continue to be exercisable through August 14, 2020 at a per share exercise price of $1.00. The warrant terms provide that if the Company’s Common Stock trades above $5.00 per share as the closing price for 15 consecutive trading days at any time prior to the expiration date of the warrant, the Company has the sole discretion to accelerate the termination date of the warrant upon providing 60 days advanced notice to the warrant holders. On October 16, 2017, the Company initiated another Unit Option Program which terminated on December 6, 2017. This Unit Option Program enabled participants to purchase Units of the Company’s securities where each Unit (priced at $250.00 each) was comprised of (i) a certain number of shares of Common Stock determined by dividing $250.00 (the price of one Unit) by the average of the high and low sale prices of the Company’s Common Stock as reported on the NASDAQ on the unit purchase date and (ii) Common Stock purchase warrants to purchase an additional 15 shares of Common Stock at a warrant exercise price of $1.00 per share. The warrant is referred to as “ZNWAG.” The warrants became exercisable on January 8, 2018 and continue to be exercisable through January 8, 2021 at a per share exercise price of $1.00. The warrant terms provide that if the Company’s Common Stock trades above $5.00 per share as the closing price for 15 consecutive trading days at any time prior to the expiration date of the warrant, the Company has the sole discretion to accelerate the termination date of the warrant upon providing 60 days advanced notice to the warrant holders. On February 1, 2018, the Company initiated another Unit Option Program which terminated on February 28, 2018. The Unit Option consisted of Units of our securities where each Unit (priced at $250.00 each) was comprised of (i) 50 shares of Common Stock and (ii) Common Stock purchase warrants to purchase an additional 50 shares of Common Stock. The investor’s Plan account was credited with the number of shares of the Company’s Common Stock acquired under the Units purchased. Each warrant affords the investor the opportunity to purchase one share of Company Common Stock at a warrant exercise price of $5.00. The warrant is referred to as “ZNWAH.” The warrants became exercisable on April 2, 2018 and continue to be exercisable through April 2, 2020 at a per share exercise price of $5.00, after the Company, on December 4, 2018, extended the termination date of the Warrant by one (1) year from the expiration date of April 2, 2019 to April 2, 2020. On August 21, 2018, the Company initiated another Unit Option, and it terminated on September 26, 2018. The Unit Option consisted of Units of the Company’s securities where each Unit (priced at $250.00 each) was comprised of (i) a certain number of shares of Common Stock determined by dividing $250.00 (the price of one Unit) by the average of the high and low sale prices of the Company’s publicly traded common stock as reported on the NASDAQ on the Unit Purchase Date and (ii) Common Stock purchase warrants to purchase an additional twenty-five (25) shares of Common Stock. The investor’s Plan account was credited with the number of shares of the Company’s Common Stock acquired under the Units purchased. Each warrant affords the investor the opportunity to purchase one share of Company Common Stock at a warrant exercise price of $1.00. The warrant is referred to as “ZNWAJ.” The warrants became exercisable on October 29, 2018 and continue to be exercisable through October 29, 2020 at a per share exercise price of $1.00, after the Company, on December 4, 2018, extended the termination date of the Warrant by one (1) year from the expiration date of October 19, 2019 to October 29, 2020. On December 10, 2018, the Company initiated another Unit Option and it terminated on January 23, 2019. The Unit Option consisted of Units of the Company’s securities where each Unit (priced at $250.00 each) is comprised of (i) two hundred and fifty (250) shares of Common Stock and (ii) Common Stock purchase warrants to purchase an additional two hundred and fifty (250) shares of Common Stock at a per share exercise price of $0.01. The investor’s Plan account was credited with the number of shares of the Company’s Common Stock and Warrants that are acquired under the Units purchased. Each warrant affords the participant the opportunity to purchase one share of our Common Stock at a warrant exercise price of $0.01. The warrant is referred to as “ZNWAK.” The warrants became exercisable on February 25, 2019 and continue to be exercisable through February 25, 2020 at a per share exercise price of $0.01. On April 24, 2019, the Company’s most recent Unit Option began and is scheduled to terminate on June 6, 2019. The Unit Option consists of Units of the Company’s securities where each Unit (priced at $250.00 each) is comprised of (i) two hundred and fifty (250) shares of Common Stock and (ii) Common Stock purchase warrants to purchase an additional fifty (50) shares of Common Stock at a per share exercise price of $2.00. The investor’s Plan account will be credited with the number of shares of the Company’s Common Stock and Warrants that are acquired under the Units purchased. For Plan participants who enroll into the Unit Program with the purchase of at least one Unit and also enroll in the separate Automatic Monthly Investments (“AMI”) program at a minimum of $50.00 per month or more, will receive an additional twenty-five (25) warrants at an exercise price of $2.00 during this Unit Option Program. The twenty-five (25) additional warrants are for enrolling into the AMI program. Existing subscribers to the AMI are entitled to the additional twenty-five (25) warrants once, if they purchase at least one (1) unit during the Unit program. Each warrant affords the participant the opportunity to purchase one share of our Common Stock at a warrant exercise price of $2.00. The warrant is referred to as “ZNWAL.” The warrants will become exercisable on August 6, 2019 and continue to be exercisable through August 6, 2021 at a per share exercise price of $2.00. For the three months ended March 31, 2019, net proceeds of approximately $2,528,000 was raised under the DSPP program. The warrants represented by the ticker ZNWAA are tradable on the NASDAQ market. However, all of the other warrants characterized above, in the table below, and throughout this Form 10-Q, are not tradeable and are used internally for classification and accounting purposes only. F. Warrant Descriptions The price and the expiration dates for the series of warrants to investors are as follows * : Period of Grant US$ Expiration Date ZNWAA Warrants March 2013 – December 2014 2.00 January 31, 2020 ZNWAD Warrants** January 2015 – March 2016 1.00 May 02, 2020 ZNWAE Warrants November 2016 – March 2017 1.00 May 01, 2020 ZNWAF Warrants** May 2017 – July 2017 1.00 August 14, 2020 ZNWAG Warrants October 2017 – December 2017 1.00 January 08, 2021 ZNWAH Warrants** February 2018 5.00 April 2, 2020 ZNWAI Warrants** April 2018 – May 2018 3.00 June 29, 2020 ZNWAJ Warrants August 2018 – September 2018 1.00 October 29, 2020 ZNWAK Warrants December 2018 – January 2019 0.01 February 25, 2020 * Zion’s ZNWAB Warrants expired on May 2, 2017 and its ZNWAC Warrants expired on May 2, 2018 ** On December 4, 2018, the Company extended the termination date of the Warrants by one (1) year. G. Subscription Rights Offering On April 2, 2018 the Company announced an offering (“2018 Subscription Rights Offering”) through American Stock Transfer & Trust Company, LLC (the “Subscription Agent”), at no cost to the shareholders, of non-transferable Subscription Rights to purchase Rights (each “Right” and collectively, the “Rights”) of its securities to persons who owned shares of our Common Stock on April 13, 2018 (“the Record Date”). Pursuant to the 2018 Subscription Rights Offering, each holder of shares of common stock on the Record Date received non-transferable rights to subscribe for Rights, with each Right comprised of one share of the Company Common Stock, par value $0.01 per share (the “Common Stock”) and one Common Stock Purchase Warrant to purchase an additional one share of Common Stock. Each Right could be purchased at a per Right subscription price of $5.00. Each Warrant affords the investor the opportunity to purchase one share of the Company Common Stock at a warrant exercise price of $3.00. The warrant is referred to as “ZNWAI.” The warrants became exercisable on June 29, 2018 and continue to be exercisable through June 29, 2020 at a per share exercise price of $3.00, after the Company, on December 4, 2018, extended the termination date of the Warrant by one (1) year from the expiration date of June 29, 2019 to June 29, 2020. Each shareholder received .10 (one tenth) of a subscription right (i.e. one subscription right for each 10 shares owned) for each share of the Company’s Common Stock owned on the Record Date. The 2018 Subscription Rights Offering terminated on May 31, 2018. The Company raised net proceeds of approximately $3,038,000, from the Rights Offering, after deducting related fees and expenses of $243,000. H. Warrant Table The warrant transactions since January 1, 2019 are shown in the table below: Warrants Exercise Price Warrant Termination Date Beg Balance, 12/31/18 Warrants Issued Warrants Exercised Warrants Expired Outstanding Balance, 3/31/19 ZNWAA $ 2.00 1/31/2020 1,498,804 0 0 0 1,498,804 ZNWAD $ 1.00 5/2/2020 243,853 0 0 0 243,853 ZNWAE $ 1.00 5/2/2020 2,144,510 0 0 0 2,144,510 ZNWAF $ 1.00 8/14/2020 359,610 0 0 0 359,610 ZNWAG $ 1.00 1/8/2021 240,578 0 0 0 240,578 ZNWAH $ 5.00 4/19/2020 372,400 0 0 0 372,400 ZNWAI $ 3.00 6/29/2020 640,735 0 0 0 640,735 ZNWAJ $ 1.00 10/29/2020 546,050 0 0 0 546,050 ZNWAK $ 0.01 2/25/2020 0 673,650 (157,605 ) 0 516,045 Outstanding warrants 6,046,540 673,650 (157,605 ) 0 6,562,585 I. Warrants Extended On December 4, 2018, the Company executed an Amendment to certain Warrant Agent Agreements (the “Agreements”) between the Company and American Stock Transfer & Trust Company (“AST”). The Company has implemented Agreements with AST as the Company’s Warrant Agent (the “Warrant Agent”), under a Warrant Agent Agreement dated February 2, 2015 for the Warrant ZNWAD, under a Warrant Agent Agreement dated February 1, 2018 for the Warrant ZNWAH, under a Warrant Agent Agreement dated April 2, 2018 for the Warrant ZNWAI and under a Warrant Agent Agreement dated August 21, 2018 for the Warrant ZNWAJ. The Warrant ZNWAD had an expiration date of May 2, 2019, the Warrant ZNWAH had an expiration date of April 19, 2019, the Warrant ZNWAI had an expiration date of June 29, 2019 and the Warrant ZNWAJ had an expiration date of October 29, 2019. Pursuant to Section 3.2 of the Warrant Agent Agreements, the Company in its sole discretion extended the termination date of the above Warrants by delaying the Expiration Dates, and such extension was to be identical in duration among all of the Warrants. The Company extended the duration of the Warrant ZNWAD by one (1) year from the expiration date of May 2, 2019 to May 2, 2020. The Company extended the duration of the Warrant ZNWAH by one (1) year from the expiration date of April 19, 2019 to April 19, 2020. The Company extended the duration of the Warrant ZNWAI by one (1) year from the expiration date of June 29, 2019 to June 29, 2020. The Company extended the duration of the Warrant ZNWAJ by one (1) year from the expiration date of October 29, 2019 to October 29, 2020.

Unproved Oil and Gas Properties

Unproved Oil and Gas Properties, Full Cost Method	3 Months Ended
	Mar. 31, 2019
Unproved Oil and Gas Properties, Full Cost Method [Abstract]
Unproved Oil and Gas Properties, Full Cost Method	Note 4 - Unproved Oil and Gas Properties, Full Cost Method Unproved oil and gas properties, under the full cost method, are comprised as follows: March 31, December 31, US$ thousands US$ thousands Excluded from amortization base: Drilling costs, and other operational related costs 1,242 1,242 Capitalized salary costs 1,625 1,579 Capitalized interest costs 687 677 Legal costs, license fees and other preparation costs 3,344 3,216 Other costs 2 - 6,900 6,714 * The unproved oil and gas properties balance at March 31, 2019 contains approximately $587,000 in unpaid amounts. Impairment of unproved oil and gas properties comprised as follows: March 31, March 31, US$ thousands US$ Excluded from amortization base: Drilling costs, and other operational related costs 142 - Other costs 21 - 163 - Changes in Unproved oil and gas properties during the three months ended March 31, 2019 and 2018 are as follows: March 31, March 31, US$ thousands US$ thousands Excluded from amortization base: Drilling costs, and other operational related costs - 3,466 Capitalized salary costs 46 337 Capitalized interest costs 10 86 Legal costs, license fees and other preparation costs 128 278 Other costs 2 72 186 4,239

Senior Convertible Bonds

Senior Convertible Bonds	3 Months Ended
	Mar. 31, 2019
Senior Convertible Bonds [Abstract]
Senior Convertible Bonds	Note 5 - Senior Convertible Bonds Rights Offering -10% Senior Convertible Notes due May 2, 2021 On October 21, 2015, the Company filed with the SEC a prospectus supplement for a rights offering. Under the rights offering, the Company distributed at no cost, 360,000 non-transferable subscription rights to subscribe for, on a per right basis, two 10% Convertible Senior Bonds par $100 due May 2, 2021 (the “Notes”), to shareholders of the Company’s Common Stock on October 15, 2015, the record date for the offering. Each whole subscription right entitled the participant to purchase two convertible bonds at a purchase price of $100 per bond. Effective October 21, 2015, the Company executed a Supplemental Indenture, as issuer, with the American Stock Transfer & Trust Company, LLC, a New York limited liability trust company (“AST”), as trustee for the Notes (the “Indenture”). On March 31, 2016, the rights offering terminated. On May 2, 2016, the Company issued approximately $3,470,000 aggregate principal amount of Notes in connection with the rights offering. The Company received net proceeds of approximately $3,334,000, from the issuance of the Notes, after deducting fees and expenses of $136,000 incurred in connection with the offering. These costs have been discounted as deferred offering costs. The Notes contain a convertible option that gives rise to a derivative liability, which is accounted for separately from the Notes (see below and Note 6). Accordingly, the Notes were initially recognized at fair value of approximately $1,844,000, which represents the principal amount of $3,470,000 from which a debt discount of approximately $1,626,000 (which is equal to the fair value of the convertible option) was deducted. During the three months ended March 31, 2019, the Company recorded approximately $6,000 in amortization expense related to the deferred financing costs, approximately $93,000 in debt discount amortization, and approximately $1,000 related to financing costs associated with notes converted to shares. The Notes are governed by the terms of the Indenture. The Notes are senior unsecured obligations of the Company and bear interest at a rate of 10% per year, payable annually in arrears on May 2 of each year, commencing May 2, 2017. The Notes will mature on May 2, 2021, unless earlier redeemed by the Company or converted by the holder. Interest and principal may be paid, at the Company’s option, in cash or in shares of the Company’s Common Stock. The number of shares for the payment of interest in shares of Common Stock, in lieu of the cash amount, will be based on the average of the closing prices of the Company’s Common Stock as reported by Bloomberg L.P. for the 30 trading days preceding the record date for the payment of interest; such record date has been designated and will always be the 10 th On May 2, 2019, the Company paid its annual 10% interest to its bondholders of record on April 18, 2019. The interest was paid-in-kind (“PIK”) in the form of Common Stock. An average of the Company stock price of $0.774 was determined based on the 30 trading days prior to the record date of April 18, 2019. This figure was used to divide into 10% of the par value of the bonds held by the holders. The Company issued 422,248 shares to the accounts of its bondholders. At any time prior to the close of business on the business day immediately preceding April 2, 2021, holders may convert their notes into Common Stock at the conversion rate of 44 shares per $100 bond (which is equivalent to a conversion rate of approximately $2.27 per share). The conversion rate is subject to adjustment from time to time upon the occurrence of certain events, including, but not limited to, the issuance of stock dividends and payment of cash dividends. Beginning May 3, 2018, the Company was entitled to redeem for cash the outstanding Notes at an amount equal to the principal and accrued and unpaid interest, plus a 10% premium. No “sinking fund” is provided for the Notes due May 2021, which means that the Company is not required to periodically redeem or retire the Notes due May 2021. Through the three months ended March 31, 2019 approximately 10 convertible bonds of $100 each, have been converted at a conversion rate of approximately $2.27 per share. As a result, the Company issued approximately 440 shares of its Common Stock and recorded approximately ($1,000) in financial expenses during the same period. March 31, December 31, US$ US$ 10% Senior Convertible Bonds, on the day of issuance $ 3,470 $ 3,470 Unamortized Debt discount, net $ (900 ) $ (993 ) Bonds converted to shares $ (204 ) $ (203 ) Offering cost, net $ (57 ) $ (63 ) 10% senior Convertible bonds – Long Term Liability $ 2,309 $ 2,211 The Company recognized $10,000 and $86,000 in capitalized interest for the three months ended March 31, 2019, and 2018, respectively. The Company recognized $71,000 and $0 interest expense for the three months ended March 31, 2019, and 2018, respectively.

Derivative Liability

Derivative Liability	3 Months Ended
	Mar. 31, 2019
Derivative Liability [Abstract]
Derivative Liability	Note 6 - Derivative Liability The Notes issued by the Company and discussed in Note 5 contain a convertible option that gives rise to a derivative liability. The debt instrument the Company issued includes a make-whole provision, which provides that in the event of conversion by the investor under certain circumstances, the issuer is required to deliver to the holder additional consideration beyond the settlement of the conversion obligation. Because time value make-whole provisions are not clearly and closely related to the debt host and would meet the definition of a derivative if considered freestanding, they are evaluated under the indexation guidance to determine whether they would be afforded the scope exception pursuant to ASC 815-10-15-74(a). This evaluation is generally performed in conjunction with the analysis of the embedded conversion feature. The Company has measured its derivative liability at fair value and recognized the derivative value as a current liability and recorded the derivative value on its balance sheet. The fair value of the shares to be issued upon conversion of the Notes was recorded as a derivative liability, with the change in the fair value recorded as a gain or loss in the accompanying statement of operations. The valuation of the Notes was done by using the Binomial Model, a well-accepted option-pricing model, and based on the Notes’ terms and other parameters the Company identified as relevant for the valuation of the Notes’ Fair Value. The Binomial Model used the forecast of the Company share price during the Note’s contractual term. As of March 31, 2019, the Company’s liabilities that are measured at fair value are as follows: March 31, December 31, Level 3 Total Level 3 Total US$ US$ US$ US$ Fair value of derivative liability 723 723 345 345 Change in value of derivative liability during 2019 are as follows: US$ Derivative liability fair value at December 31, 2018 345 Loss on derivative liability 378 Derivative liability fair value at March 31, 2019 723 The following table presents the assumptions that were used for the model as of March 31, 2019: March 31, December 31, Convertible Option Fair Value of approximately $ 723,000 $ 345,000 Annual Risk-free Rate 2.27 % 2.47 % Volatility 123.19 % 115.35 % Expected Term (years) 2.09 2.34 Convertible Notes Face Value $ 3,265,700 $ 3,266,700 Expected annual yield on Regular Notes 28.77 % 28.77 % Price of the Underlying Stock $ 0.76 $ 0.42 During the three months ended March 31, 2019, the Company recorded a loss of approximately $378,000 (net) within the Statements of Operations on derivative liability. A slight change in an unobservable input like volatility could have a significant impact on the fair value measurement of the derivative liability.

Right of Use Leases Assets and

Right of Use Leases Assets and Leases Obligations	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Right of use leases assets and leases obligations	Note 7 – Right of use leases assets and leases obligations The Company is a lessee in several non-cancelable operating leases, primarily for transportation and office spaces. The table below presents the operating lease assets and liabilities recognized on the balance sheets as of March 31, 2019: March 31, December 31, US$ US$ Operating lease assets $ 730 $ - Operating lease liabilities: Current operating lease liabilities $ 210 $ - Non-current operating lease liabilities $ 564 $ - Total operating lease liabilities $ 774 $ - The depreciable lives of operating lease assets and leasehold improvements are limited by the expected lease term. The Company’s leases generally do not provide an implicit rate, and therefore the Company uses its incremental borrowing rate as the discount rate when measuring operating lease liabilities. The incremental borrowing rate represents an estimate of the interest rate the Company would incur at lease commencement to borrow an amount equal to the lease payments on a collateralized basis over the term of a lease within a particular currency environment. The Company used incremental borrowing rates as of January 1, 2019 for operating leases that commenced prior to that date. The Company’s weighted average remaining lease term and weighted average discount rate for operating leases as of March 31, 2019 are: March 31, Weighted average remaining lease term (years) 3.8 Weighted average discount rate 6.0 % The table below reconciles the undiscounted future minimum lease payments (displayed by year and in the aggregate) under non-cancelable operating leases with terms of more than one year to the total operating lease liabilities recognized on the condensed balance sheets as of March 31, 2019: US$ April 1, 2019 through December 31, 2019 271 2020 271 2021 156 2022 134 2023 112 Thereafter - Total undiscounted future minimum lease payments 944 Less: portion representing imputed interest (170 ) Total undiscounted future minimum lease payments 774 Operating lease costs were $68,000 for the three months ended March 31, 2019. Operating lease costs are included within general and administrative expenses on the statements of income. Cash paid for amounts included in the measurement of operating lease liabilities were $71,000 for the three months ended March 31, 2019, and this amount is included in operating activities in the statements of cash flows. Right-of-use assets obtained in exchange for new operating lease liabilities were $824,000 for the three months ended March 31, 2019.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies [Abstract]
Commitments and Contingencies	Note 8 - Commitments and Contingencies A. Securities and Exchange Commission (“SEC”) Investigation As previously disclosed by the Company, on June 21, 2018, Zion received a subpoena to produce documents from the Fort Worth office of the SEC informing the Company of the existence of a non-public, fact-finding inquiry into the Company. Prior to the receipt of the subpoena on June 21, 2018, Zion had no previous communication with the SEC on this issue and was unaware of this investigation. The SEC stated that “the investigation and the subpoena do not mean that we have concluded that [Zion] or anyone else has violated the law.” To date, Zion has furnished all required documents to the SEC and will continue to fully cooperate with the investigation. The Company cannot predict when this matter will be resolved or what further action, if any, the SEC may take in connection with it. B. Litigation Following the commencement of the SEC investigation, on August 9, 2018, a putative class action (the “class action”) Complaint was filed against Zion, Victor G. Carrillo, the Company’s Chief Executive Officer at such time, and Michael B. Croswell Jr., the Company’s Chief Financial Officer (collectively, the “Defendants”) in the U.S. District Court for the Northern District of Texas. On November 16, 2018, the Court entered an Order in the class action appointing lead plaintiffs and approving lead counsel and on January 22, 2019, an Amended Complaint was filed. On February 1, 2019, a Corrected Amended Class Action Complaint was filed. The suit alleges violations of Section 10(b) of the Securities Exchange Act of 1934 (the “Exchange Act”) and Rule 10b-5 promulgated thereunder by the SEC and Section 11 of the Securities Act of 1933 (the “Securities Act”) against all defendants and alleges violations of Section 20(a) of the Exchange Act and Section 15 of the Securities Act against the individual defendants. The alleged class period is from February 13, 2018 through November 20, 2018. On March 13, 2019, a Motion to Dismiss Plaintiffs’ Corrected Amended Complaint was filed on behalf of Zion, Victor Carrillo and Michael B. Croswell, Jr., pleading numerous grounds in support of their Motion to Dismiss. By Verified Consolidated Stockholder Derivative Complaint filed on March 4, 2019, three (3) stockholder derivative lawsuits previously filed in federal district court in Delaware on September 10, 2018, November 1, 2018, and November 21, 2018 were consolidated into one lawsuit filed derivatively and purportedly on behalf of the Company against Victor G. Carrillo, Michael B. Croswell, Jr., John M. Brown, Dustin L. Guinn, Forest A. Garb, Kent S. Siegel, Paul Oroian, William H. Avery, the Estate of Yehezkel Druckman, Lee Russell, Justin W. Furnace, Gene Scammahorn, Ralph F. DeVore, and Martin M. van Brauman. The suit alleges breach of fiduciary duty, unjust enrichment, violations of Section 14(a) of the Exchange Act and conspiracy to “facilitate and disguise” other alleged wrongdoings. The “Relevant Period” of alleged wrongdoing spans from February 13, 2018 and continues through the present. The suit seeks unspecified damages to be awarded to the Company, orders directing the Company and individual defendants to make certain corporate governance reforms, restitution, and fees and costs. On April 18, 2019, a Motion to Dismiss Plaintiffs’ Complaint was filed on behalf of all defendants pleading numerous grounds in support of their Motion to Dismiss. On September 25, 2018, another lawsuit was filed in the 68 th On October 29, 2018, Zion received a shareholder request to inspect books and records pursuant to Section 220 of the Delaware General Corporation Law for the purpose of investigating potential corporate mismanagement and breaches of fiduciary duty in connection with public statements made by the Company from March 12, 2018 to May 30, 2018. The Company responded to this request. The Company disputes the above claims and has made an advanced deposit of $500,000 to defense counsel for the cost of defending the litigation. The Company carries insurance that is applicable to these claims. Because of the uncertainties of litigation, it is not feasible to predict or determine the outcome of these matters, to guarantee that there will be no liability, or to reasonably estimate any loss in excess of its coverage. However, the Company intends to pursue a vigorous defense to the claims. From time to time, the Company may also be subject to routine litigation, claims or disputes in the ordinary course of business. The Company defends itself vigorously in all such matters. However, we cannot predict the outcome or effect of any of the litigation or any other pending litigation or claims. C. Environmental and Onshore Licensing Regulatory Matters The Company is engaged in oil and gas exploration and production and may become subject to certain liabilities as they relate to environmental cleanup of well sites or other environmental restoration procedures and other obligations as they relate to the drilling of oil and gas wells or the operation thereof. Various guidelines have been published in Israel by the State of Israel’s Petroleum Commissioner and Energy and Environmental Ministries as it pertains to oil and gas activities. Mention of these older guidelines was included in previous Zion Oil & Gas filings. On March 15, 2018, the Energy Ministry issued new guidelines regarding a uniform reporting manner by which the operator must submit to the Commissioner data and materials regarding lawful exploration and production activities. The guidelines detail the timeline, data, forms, format, media and materials (such as rock cuttings, cores, gas and oil samples) that must be submitted for seismic and drilling activities. The Company believes that these new regulations are likely to continue to increase the expenditures associated with obtaining new exploration rights and drilling new wells. The Company expects that an additional financial burden could occur as a result of requiring cash reserves that could otherwise be used for operational purposes. In addition, these new regulations are likely to continue to increase the time needed to obtain all of the necessary authorizations and approvals to drill and production test exploration wells. D. Bank Guarantees As of March 31, 2019, the Company provided Israeli-required bank guarantees to various governmental bodies (approximately $1,009,000) and others (approximately $82,000) with respect to its drilling operation in an aggregate amount of approximately $1,091,000. The (cash) funds backing these guarantees and additional amounts added to support currency fluctuations as required by the bank are held in restricted interest-bearing accounts and are reported on the Company’s balance sheets as fixed short-term bank deposits – restricted, and fixed long-term bank deposits – restricted. E. Risks Market risk is a broad term for the risk of economic loss due to adverse changes in the fair value of a financial instrument. These changes may be the result of various factors, including interest rates, foreign exchange rates, commodity prices and/or equity prices. In the normal course of doing business, we are exposed to the risks associated with foreign currency exchange rates and changes in interest rates. Foreign Currency Exchange Rate Risks. Interest Rate Risk. The primary objective of our investment activities is to preserve principal while at the same time maximizing yields without significantly increasing risk. To achieve this objective, we invest our excess cash in short-term bank deposits and money market funds that may invest in high quality debt instruments.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Note 9 - Subsequent Events (i) Approximately $504,000 was collected through the Company’s DSPP program during the period April 1 through 30, 2019. (ii) On May 1, 2019, options to purchase 100,000 shares of Common Stock were granted to one senior office at an exercise price of $0.01 per share. The options are exercisable through May 1, 2029. However, the vesting and exercisability of these options is subject to the following schedule: (a) 50,000 options vest on September 1, 2019 and (b) the remaining 50,000 options vest on January 1, 2020. The fair value of the options at the date of grant amounted to $55,000.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Summary of Significant Accounting Policies [Abstract]
Net Gain (Loss) per Share Data	A. Net Gain (Loss) per Share Data Basic and diluted net (loss) gain per share of common stock, par value $0.01 per share (“Common Stock”), is presented in conformity with ASC 260-10 “Earnings Per Share.” Diluted net loss per share is the same as basic net loss per share, as the inclusion of 9,651,835 and 9,651,569 Common Stock equivalents in the three-month period ended March 31, 2019 and 2018 respectively, would be anti-dilutive.
Use of Estimates	B. Use of Estimates The preparation of the accompanying financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities, and reported amounts of revenues and expenses. Such estimates include the valuation of unproved oil and gas properties, deferred tax assets, asset retirement obligations and legal contingencies. These estimates and assumptions are based on management’s best estimates and judgment. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, which management believes to be reasonable under the circumstances. The Company adjusts such estimates and assumptions when facts and circumstances dictate. Illiquid credit markets, volatile equity, foreign currency, and energy markets have combined to increase the uncertainty inherent in such estimates and assumptions. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in those estimates resulting from continuing changes in the economic environment will be reflected in the financial statements in future periods.
Oil and Gas Properties and Impairment	C. Oil and Gas Properties and Impairment The Company follows the full-cost method of accounting for oil and gas properties. Accordingly, all costs associated with acquisition, exploration and development of oil and gas reserves, including directly related overhead costs, are capitalized. All capitalized costs of oil and gas properties, including the estimated future costs to develop proved reserves, are amortized on the unit-of-production method using estimates of proved reserves. Investments in unproved properties and major development projects are not amortized until proved reserves associated with the projects can be determined or until impairment occurs. If the results of an assessment indicate that the properties are impaired, the amount of the impairment is included in loss from continuing operations before income taxes, and the adjusted carrying amount of the proved properties is amortized on the unit-of-production method. The Company’s oil and gas property represents an investment in unproved properties. These costs are excluded from the amortized cost pool until proved reserves are found or until it is determined that the costs are impaired. All costs excluded are reviewed at least quarterly to determine if impairment has occurred. The amount of any impairment is charged to expense since a reserve base has not yet been established. Impairment requiring a charge to expense may be indicated through evaluation of drilling results, relinquishing drilling rights or other information. During the fourth quarter of 2018, the Company testing protocol was concluded at the Megiddo Jezreel #1 (“MJ #1”) well. The test results confirmed that the MJ #1 well did not contain hydrocarbons in commercial quantities in the zones tested. As a result of the above determination, in the year ended December 31, 2018, the Company recorded a non-cash impairment charge to its unproved oil and gas properties of $30,906,000 (see Note 4). During the first quarter of 2019, the Company recorded a post-impairment charge of approximately $163,000. Currently, the Company has no economically recoverable reserves and no amortization base. The Company’s unproved oil and gas properties consist of capitalized exploration costs of $6,900,000 and $6,714,000 as of March 31, 2019, and December 31, 2018, respectively.
Fair Value Measurements	D. Fair Value Measurements The Company follows Accounting Standards Codification (ASC) 820, “Fair Value Measurements and Disclosures,” as amended by Financial Accounting Standards Board (FASB) Financial Staff Position (FSP) No. 157 and related guidance. Those provisions relate to the Company’s financial assets and liabilities carried at fair value and the fair value disclosures related to financial assets and liabilities. ASC 820 defines fair value, expands related disclosure requirements, and specifies a hierarchy of valuation techniques based on the nature of the inputs used to develop the fair value measures. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date, assuming the transaction occurs in the principal or most advantageous market for that asset or liability. There are three levels of inputs to fair value measurements - Level 1, meaning the use of quoted prices for identical instruments in active markets; Level 2, meaning the use of quoted prices for similar instruments in active markets or quoted prices for identical or similar instruments in markets that are not active or are directly or indirectly observable; and Level 3, meaning the use of unobservable inputs. The Company uses Level 1 inputs for its fair value measurements whenever there is an active market, with actual quotes, market prices, and observable inputs on the measurement date. The Company uses Level 2 inputs for fair value measurements whenever there are quoted prices for similar securities in an active market or quoted prices for identical securities in an inactive market. The Company uses Level 3 inputs in the Binomial Model used for the valuation of the derivative liability.
Derivative Liabilities	E. Derivative Liabilities In accordance with ASC 815-40-25 and ASC 815-10-15 Derivatives and Hedging and ASC 480-10-25 Liabilities-Distinguishing Liabilities from Equity, the embedded derivatives associated with the Convertible Bonds are accounted for as a liability during the term of the related Convertible Bonds (see Note 6).
Stock-Based Compensation	F. Stock-Based Compensation ASC 718, “Compensation – Stock Compensation,” prescribes accounting and reporting standards for all share-based payment transactions in which employee services are acquired. Transactions include incurring liabilities, or issuing or offering to issue shares, options, and other equity instruments such as employee stock ownership plans and stock appreciation rights. Share-based payments to employees, including grants of employee stock options, are recognized as compensation expense in the financial statements based on their fair values. That expense is recognized over the period during which an employee is required to provide services in exchange for the award, known as the requisite service period (usually the vesting period). The Company accounts for stock-based compensation issued to non-employees and consultants in accordance with the provisions of ASC 505-50, “Equity – Based Payments to Non-Employees.” Measurement of share-based payment transactions with non-employees is based on the fair value of whichever is more reliably measurable: (a) the goods or services received; or (b) the equity instruments issued. The fair value of the share-based payment transaction is determined at the earlier of performance commitment date or performance completion date.
Related parties	G. Related parties Parties are considered to be related to the Company if the parties, directly or indirectly, through one or more intermediaries, control, are controlled by, or are under common control with the Company. Related parties also include principal owners of the Company, its management, members of the immediate families of principal owners of the Company and its management and other parties with which the Company may deal if one party controls or can significantly influence the management or operating policies of the other to an extent that one of the transacting parties might be prevented from fully pursuing its own separate interests. All transactions with related parties are recorded at fair value of the goods or services exchanged.
Recently Adopted Accounting Pronouncements	H. Recently Adopted Accounting Pronouncements ASU 2016-02 and ASU 2018-01 – Leases (Topic 842) In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-02, Leases (Topic 842) (“ASU 2016-02”) in order to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet for those leases classified as operating leases under previous GAAP. ASU 2016-02 requires that a lessee should recognize a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term on the balance sheet. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 (including interim periods within those periods) using a modified retrospective approach and early adoption is permitted. Zion adopted ASU 2016-02 in the first quarter of 2019. Presently, Zion has operating leases for office space in Dallas, Texas and in Caesarea, Israel plus various leases for motor vehicles. These leases have been accounted for under ASU 2016-02 in 2019 by establishing a right-of-use asset and a corresponding current lease liability and non-current lease liability. Zion is not subject to any loan covenants and therefore, the increase in assets and liabilities does not have a material impact on its business. In January 2018, the FASB issued ASU 2018-01, “Land Easement Practical Expedient for Transition to “Topic 842.” The amendments in this Update provide an optional transition practical expedient to not evaluate under Topic 842 existing or expired land easements that were not previously accounted for as leases under Topic 840, Leases. An entity that elects this practical expedient should evaluate new or modified land easements under Topic 842 beginning at the date that the entity adopts Topic 842. An entity that does not elect this practical expedient should evaluate all existing or expired land easements in connection with the adoption of the new lease requirements in Topic 842 to assess whether they meet the definition of a lease. The Company does not have any land easements and believes that this ASU 2018-01 has no effect on the Company. ASU 2016-15 and ASU 2016-08 – Statement of Cash Flows (Topic 230) In August 2016, the FASB issued AS 2016-15, “Classification of Certain Cash Receipts and Cash Payments”, which clarifies how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The effective date for ASU 2016-15 is for fiscal years beginning after December 15, 2018, and interim periods within fiscal years beginning after December 15, 2019. Early adoption is permitted. The Company is currently evaluating the impact of adopting ASU 2016-15 on our financial statements. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230) (“ASU 2016-18”), which requires that restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total cash amounts shown on the statement of cash flows. The effective date for ASU 2016-18 is for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. We adopted ASU 2016-18 effective January 1, 2018. The adoption of ASU 2016-18 had no impact on our retained earnings, and no impact to our net income on an ongoing basis. Adoption of the new standard requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents and amounts generally described as restricted cash, or restricted cash equivalents. The amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statements of cash flows. The amendments have been applied using a retrospective transition method to each period presented, as required. The period ended March 31, 2019 has been reclassified to reflect this change. In March 2018, the FASB issued ASU 2018-05, “Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118”. This ASU expresses the view of the staff regarding application of Topic 740, Income Taxes, in the reporting period that includes December 22, 2017, the date on which the Tax Cuts and Jobs Act (H.R.1, An Act to Provide for Reconciliation Pursuant to Titles II and V of the Concurrent Resolution on the Budget for Fiscal Year 2018) was signed into law. The Company is currently evaluating the impact of adopting ASU 2018-05 on our financial statements. ASU 2016-09 In March 2016, the FASB issued ASU No. 2016-09, Compensation – Stock Compensation, or ASU No. 2016-09. The areas for simplification in this Update involve several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. For public entities, the amendments in this Update are effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted in any interim or annual period. If an entity early adopts the amendments in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes that interim period. An entity that elects early adoption must adopt all of the amendments in the same period. Amendments related to the timing of when excess tax benefits are recognized, minimum statutory withholding requirements, forfeitures, and intrinsic value should be applied using a modified retrospective transition method by means of a cumulative-effect adjustment to equity as of the beginning of the period in which the guidance is adopted. Amendments related to the presentation of employee taxes paid on the statement of cash flows when an employer withholds shares to meet the minimum statutory withholding requirement should be applied retrospectively. Amendments requiring recognition of excess tax benefits and tax deficiencies in the income statement and the practical expedient for estimating expected term should be applied prospectively. An entity may elect to apply the amendments related to the presentation of excess tax benefits on the statement of cash flows using either a prospective transition method or a retrospective transition method. The Company believes that this ASU No. 2016-09 has no impact on our financial statements. The Company does not believe that the adoption of any recently issued accounting pronouncements in 2019 had a significant impact on our financial position, results of operations, or cash flow, except for ASC Update No. 2015-03—Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, which requires debt issuance costs to be presented in the balance sheet as a direct deduction from the carrying value of the associated debt liability, consistent with the presentation of a debt discount. For public business entities, the amendments in this Update are effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. At March 31, 2019 and December 31, 2018, the Company reclassified $57,000 and $63,000, respectively, in deferred offering costs from an asset account and applied it to the outstanding debt balance (see Note 5).

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of stock option transactions	Number of shares Weighted Average exercise price US$ Outstanding, December 31, 2018 4,788,443 1.37 Changes during 2019 to: Granted to employees, officers, directors and others * 25,000 0.01 Expired/Cancelled/Forfeited (330,693 ) 2.11 Exercised (52,500 ) 0.01 Outstanding, March 31, 2019 4,430,250 1.33 Exercisable, March 31, 2019 4,420,250 1.33 * The receipt of a stock option grant by the grantee recipient is a non-taxable event according to the Internal Revenue Service. The grantee who later chooses to exercise penny stock options must recognize the market value in income in the year of exercise.
Schedule of stock options outstanding	Shares underlying outstanding options (non-vested) Shares underlying outstanding options (fully vested) Range of exercise price Number outstanding Weighted average remaining contractual life (years) Weighted Average Exercise price Range of exercise price Number Outstanding Weighted average remaining contractual life (years) Weighted Average Exercise price US$ US$ US$ US$ — — — — 0.01 15,000 4.62 0.01 — — — — 0.01 15,000 5.00 0.01 — — — — 0.01 5,000 5.20 0.01 — — — — 0.01 10,000 6.50 0.01 — — — — 0.01 25,000 6.75 0.01 — — — — 0.01 305,000 7.18 0.01 — — — — 0.01 525,000 7.75 0.01 — — — — 0.01 10,000 7.76 0.01 — — — — 0.01 60,000 8.04 0.01 0.01 10,000 8.75 0.01 0.01 30,000 8.50 0.01 — — — — 0.01 180,000 8.75 0.01 — — — — 0.01 85,000 8.76 0.01 — — — — 0.01 *45,000 8.91 0.01 — — — — 0.01 6,000 9.01 0.01 — — — — 0.01 25,000 9.77 0.01 — — — — 1.33 25,000 4.08 1.33 — — — — 1.38 108,000 1.76 1.38 — — — — 1.38 113,057 5.76 1.38 — — — — 1.55 400,000 3.18 1.55 — — — — 1.67 340,000 1.51 1.67 — — — — 1.67 428,193 5.51 1.67 — — — — 1.70 233,500 3.73 1.70 — — — — 1.75 400,000 4.27 1.75 — — — — 1.78 25,000 5.44 1.78 — — — — 1.87 25,000 2.84 1.87 — — — — 1.95 25,000 1.01 1.95 — — — — 1.96 25,000 0.43 1.96 — — — — 2.03 25,000 2.09 2.03 — — — — 2.31 400,000 4.76 2.31 2.61 481,500 2.68 2.61 — — — — 4.15 25,000 5.26 4.15 0.01 10,000 0.01 0.01-4.15 4,420,250 1.32 * 27,500 are exercisable on June 30, 2019.
Schedule of compensation cost of warrant and option issuances	For the three months ended March 31, 2019 2018 US$ thousands US$ thousands — 297
Schedule of warrants description	Period of Grant US$ Expiration Date ZNWAA Warrants March 2013 – December 2014 2.00 January 31, 2020 ZNWAD Warrants** January 2015 – March 2016 1.00 May 02, 2020 ZNWAE Warrants November 2016 – March 2017 1.00 May 01, 2020 ZNWAF Warrants** May 2017 – July 2017 1.00 August 14, 2020 ZNWAG Warrants October 2017 – December 2017 1.00 January 08, 2021 ZNWAH Warrants** February 2018 5.00 April 2, 2020 ZNWAI Warrants** April 2018 – May 2018 3.00 June 29, 2020 ZNWAJ Warrants August 2018 – September 2018 1.00 October 29, 2020 ZNWAK Warrants December 2018 – January 2019 0.01 February 25, 2020 * Zion’s ZNWAB Warrants expired on May 2, 2017 and its ZNWAC Warrants expired on May 2, 2018 ** On December 4, 2018, the Company extended the termination date of the Warrants by one (1) year.
Dividend Reinvestment and Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of warrants description	Warrants Exercise Price Warrant Termination Date Beg Balance, 12/31/18 Warrants Issued Warrants Exercised Warrants Expired Outstanding Balance, 3/31/19 ZNWAA $ 2.00 1/31/2020 1,498,804 0 0 0 1,498,804 ZNWAD $ 1.00 5/2/2020 243,853 0 0 0 243,853 ZNWAE $ 1.00 5/2/2020 2,144,510 0 0 0 2,144,510 ZNWAF $ 1.00 8/14/2020 359,610 0 0 0 359,610 ZNWAG $ 1.00 1/8/2021 240,578 0 0 0 240,578 ZNWAH $ 5.00 4/19/2020 372,400 0 0 0 372,400 ZNWAI $ 3.00 6/29/2020 640,735 0 0 0 640,735 ZNWAJ $ 1.00 10/29/2020 546,050 0 0 0 546,050 ZNWAK $ 0.01 2/25/2020 0 673,650 (157,605 ) 0 516,045 Outstanding warrants 6,046,540 673,650 (157,605 ) 0 6,562,585
Non-Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of assumptions used to estimate fair value of warrants granted using black-scholes option pricing model	For the three months ended March 31, 2019 2018 Weighted-average fair value of underlying stock at grant date $ — $ 3.37 Dividend yields — — Expected volatility — 73%-76 % Risk-free interest rates — 2.46%-2.81 % Expected lives (in years) — 10.00 Weighted-average grant date fair value $ — $ 3.36
Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of assumptions used to estimate fair value of warrants granted using black-scholes option pricing model	For the three months ended March 31, 2019 2018 Weighted-average fair value of underlying stock at grant date $ 0.42 $ 2.31 Dividend yields — — Expected volatility 87 % 68%-70 % Risk-free interest rates 2.53 % 2.01%-2.25 % Expected lives (in years) 5.00 3.50-5.50 Weighted-average grant date fair value $ 0.41 $ 1.69

Unproved Oil and Gas Properti_2

Unproved Oil and Gas Properties, Full Cost Method (Tables)	3 Months Ended
	Mar. 31, 2019
Unproved Oil and Gas Properties, Full Cost Method [Abstract]
Schedule of unproved oil and gas properties, full cost method	March 31, December 31, US$ thousands US$ thousands Excluded from amortization base: Drilling costs, and other operational related costs 1,242 1,242 Capitalized salary costs 1,625 1,579 Capitalized interest costs 687 677 Legal costs, license fees and other preparation costs 3,344 3,216 Other costs 2 - 6,900 6,714 March 31, March 31, US$ thousands US$ Excluded from amortization base: Drilling costs, and other operational related costs 142 - Other costs 21 - 163 -
Schedule of changes in unproved oil and gas properties	March 31, March 31, US$ thousands US$ thousands Excluded from amortization base: Drilling costs, and other operational related costs - 3,466 Capitalized salary costs 46 337 Capitalized interest costs 10 86 Legal costs, license fees and other preparation costs 128 278 Other costs 2 72 186 4,239

Senior Convertible Bonds (Table

Senior Convertible Bonds (Tables)	3 Months Ended
	Mar. 31, 2019
Senior Convertible Bonds [Abstract]
Schedule of senior convertible bonds	March 31, December 31, US$ US$ 10% Senior Convertible Bonds, on the day of issuance $ 3,470 $ 3,470 Unamortized Debt discount, net $ (900 ) $ (993 ) Bonds converted to shares $ (204 ) $ (203 ) Offering cost, net $ (57 ) $ (63 ) 10% senior Convertible bonds – Long Term Liability $ 2,309 $ 2,211

Derivative Liability (Tables)

Derivative Liability (Tables)	3 Months Ended
	Mar. 31, 2019
Derivative Liability [Abstract]
Schedule of fair value of derivative liabilities	March 31, December 31, Level 3 Total Level 3 Total US$ US$ US$ US$ Fair value of derivative liability 723 723 345 345
Schedule of change in fair value of derivative liability	US$ Derivative liability fair value at December 31, 2018 345 Loss on derivative liability 378 Derivative liability fair value at March 31, 2019 723
Schedule of assumption used for the model of derivatives liabilities	March 31, December 31, Convertible Option Fair Value of approximately $ 723,000 $ 345,000 Annual Risk-free Rate 2.27 % 2.47 % Volatility 123.19 % 115.35 % Expected Term (years) 2.09 2.34 Convertible Notes Face Value $ 3,265,700 $ 3,266,700 Expected annual yield on Regular Notes 28.77 % 28.77 % Price of the Underlying Stock $ 0.76 $ 0.42

Right of Use Leases Assets an_2

Right of Use Leases Assets and Leases Obligations (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Schedule of operating lease assets and liabilities	March 31, December 31, US$ US$ Operating lease assets $ 730 $ - Operating lease liabilities: Current operating lease liabilities $ 210 $ - Non-current operating lease liabilities $ 564 $ - Total operating lease liabilities $ 774 $ -
Schedule of weighted average remaining lease term and weighted average discount rate for operating leases	March 31, Weighted average remaining lease term (years) 3.8 Weighted average discount rate 6.0 %
Schedule of future minimum lease payments under non-cancelable operating leases	US$ April 1, 2019 through December 31, 2019 271 2020 271 2021 156 2022 134 2023 112 Thereafter - Total undiscounted future minimum lease payments 944 Less: portion representing imputed interest (170 ) Total undiscounted future minimum lease payments 774

Nature of Operations, Basis o_2

Nature of Operations, Basis of Presentation and Going Concern (Details)	Dec. 03, 2013	Mar. 31, 2019USD ($)a	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)
Nature of Operations, Basis of Presentation and Going Concern (Textual)
Area of land depth, description		The Megiddo Jezreel #1 ("MJ #1") exploratory well was spud on June 5, 2017 and drilled to a total depth ("TD") of 5,060 meters (approximately 16,600 feet). Thereafter, the Company successfully cased and cemented the well while awaiting the approval of the testing protocol. The Ministry of Energy approved the well testing protocol on April 29, 2018.
Net loss		$ (2,170,000)	$ (6,251,000)
Accumulated deficit		(201,285,000)		$ (199,115,000)
Impairment of oil and gas properties		163,000		$ 30,906,000
Post-impairment charge		$ 163,000
Megiddo-Jezreel License [Member]
Nature of Operations, Basis of Presentation and Going Concern (Textual)
Area of land, approximate | a		99,000
Initial length of lease	3 years
Megiddo-Jezreel License [Member] | Maximum [Member]
Nature of Operations, Basis of Presentation and Going Concern (Textual)
Initial length of lease	7 years
Megiddo-Jezreel License [Member] | Minimum [Member]
Nature of Operations, Basis of Presentation and Going Concern (Textual)
Initial length of lease	1 year

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Summary of Significant Accounting Policies (Textual)
Common stock equivalents excluded from EPS as the inclusion would be anti-dilutive	9,651,835	9,651,569
Common stock, par value	$ 0.01		$ 0.01
Impairment of unproved oil and gas properties	$ 163,000		$ 30,906,000
Capitalized exploration costs	6,900,000		6,714,000
Post-impairment charge	163,000
Deferred offering costs	$ 57,000		$ 63,000

Stockholders' Equity (Stock Opt

Stockholders' Equity (Stock Options) (Details) - Stock Options [Member]	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Number of shares
Outstanding, December 31, 2018 | shares	4,788,443
Granted to employees, officers, directors and others | shares	25,000	[1]
Expired/Cancelled/Forfeited | shares	(330,693)
Exercised | shares	(52,500)
Outstanding, March 31, 2019 | shares	4,430,250
Exercisable | shares	4,420,250
Weighted Average exercise price
Outstanding, December 31, 2018 | $ / shares	$ 1.37
Granted to employees, officers, directors and others | $ / shares	0.01	[1]
Expired/Cancelled/Forfeited | $ / shares	2.11
Exercised | $ / shares	0.01
Outstanding, March 31, 2019 | $ / shares	1.33
Exercisable | $ / shares	$ 1.33
[1]	The receipt of a stock option grant by the grantee recipient is a non-taxable event according to the Internal Revenue Service. The grantee who later chooses to exercise penny stock options must recognize the market value in income in the year of exercise.

Stockholders' Equity (Stock O_2

Stockholders' Equity (Stock Options Outstanding) (Details)	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Fully Vested [Member]
Shares underlying outstanding options
Range of exercise price, lower range	$ 0.01
Range of exercise price, upper range	$ 4.15
Number Outstanding | shares	4,420,250
Weighted Average Exercise price	$ 1.32
Fully Vested [Member] | Range One [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	15,000
Weighted average remaining contractual life (years)	4 years 7 months 13 days
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Range Two [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	15,000
Weighted average remaining contractual life (years)	5 years
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Range Three [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	5,000
Weighted average remaining contractual life (years)	5 years 2 months 12 days
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Range Four [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	10,000
Weighted average remaining contractual life (years)	6 years 6 months
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Range Five [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	25,000
Weighted average remaining contractual life (years)	6 years 9 months
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Range Six [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	305,000
Weighted average remaining contractual life (years)	7 years 2 months 5 days
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Range Seven [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	525,000
Weighted average remaining contractual life (years)	7 years 9 months
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Range Eight [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	10,000
Weighted average remaining contractual life (years)	7 years 9 months 3 days
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Range Nine [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	60,000
Weighted average remaining contractual life (years)	8 years 15 days
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Range Ten [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	30,000
Weighted average remaining contractual life (years)	8 years 6 months
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Range Eleven [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	180,000
Weighted average remaining contractual life (years)	8 years 9 months
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Range Twelve [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	85,000
Weighted average remaining contractual life (years)	8 years 9 months 3 days
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Ranges Thirteen [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	45,000	[1]
Weighted average remaining contractual life (years)	8 years 10 months 28 days
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Ranges Fourteen [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	6,000
Weighted average remaining contractual life (years)	9 years 4 days
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Ranges Fifteen [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	25,000
Weighted average remaining contractual life (years)	9 years 9 months 7 days
Weighted Average Exercise price	$ 0.01
Fully Vested [Member] | Ranges Sixteen [Member]
Shares underlying outstanding options
Range of exercise price	$ 1.33
Number Outstanding | shares	25,000
Weighted average remaining contractual life (years)	4 years 29 days
Weighted Average Exercise price	$ 1.33
Fully Vested [Member] | Ranges Seventeen [Member]
Shares underlying outstanding options
Range of exercise price	$ 1.38
Number Outstanding | shares	108,000
Weighted average remaining contractual life (years)	1 year 9 months 3 days
Weighted Average Exercise price	$ 1.38
Fully Vested [Member] | Ranges Eighteen [Member]
Shares underlying outstanding options
Range of exercise price	$ 1.38
Number Outstanding | shares	113,057
Weighted average remaining contractual life (years)	5 years 9 months 3 days
Weighted Average Exercise price	$ 1.38
Fully Vested [Member] | Ranges Nineteen [Member]
Shares underlying outstanding options
Range of exercise price	$ 1.55
Number Outstanding | shares	400,000
Weighted average remaining contractual life (years)	3 years 2 months 5 days
Weighted Average Exercise price	$ 1.55
Fully Vested [Member] | Ranges Twenty [Member]
Shares underlying outstanding options
Range of exercise price	$ 1.67
Number Outstanding | shares	340,000
Weighted average remaining contractual life (years)	1 year 6 months 3 days
Weighted Average Exercise price	$ 1.67
Fully Vested [Member] | Ranges Twenty One [Member]
Shares underlying outstanding options
Range of exercise price	$ 1.67
Number Outstanding | shares	428,193
Weighted average remaining contractual life (years)	5 years 6 months 3 days
Weighted Average Exercise price	$ 1.67
Fully Vested [Member] | Ranges Twenty Two [Member]
Shares underlying outstanding options
Range of exercise price	$ 1.7
Number Outstanding | shares	233,500
Weighted average remaining contractual life (years)	3 years 8 months 23 days
Weighted Average Exercise price	$ 1.7
Fully Vested [Member] | Ranges Twenty Three [Member]
Shares underlying outstanding options
Range of exercise price	$ 1.75
Number Outstanding | shares	400,000
Weighted average remaining contractual life (years)	4 years 3 months 8 days
Weighted Average Exercise price	$ 1.75
Fully Vested [Member] | Ranges Twenty Four [Member]
Shares underlying outstanding options
Range of exercise price	$ 1.78
Number Outstanding | shares	25,000
Weighted average remaining contractual life (years)	5 years 5 months 9 days
Weighted Average Exercise price	$ 1.78
Fully Vested [Member] | Ranges Twenty Five [Member]
Shares underlying outstanding options
Range of exercise price	$ 1.87
Number Outstanding | shares	25,000
Weighted average remaining contractual life (years)	2 years 10 months 3 days
Weighted Average Exercise price	$ 1.87
Fully Vested [Member] | Ranges Twenty Six [Member]
Shares underlying outstanding options
Range of exercise price	$ 1.95
Number Outstanding | shares	25,000
Weighted average remaining contractual life (years)	1 year 4 days
Weighted Average Exercise price	$ 1.95
Fully Vested [Member] | Ranges Twenty Seven [Member]
Shares underlying outstanding options
Range of exercise price	$ 1.96
Number Outstanding | shares	25,000
Weighted average remaining contractual life (years)	5 months 5 days
Weighted Average Exercise price	$ 1.96
Fully Vested [Member] | Ranges Twenty Eight [Member]
Shares underlying outstanding options
Range of exercise price	$ 2.03
Number Outstanding | shares	25,000
Weighted average remaining contractual life (years)	2 years 1 month 2 days
Weighted Average Exercise price	$ 2.03
Fully Vested [Member] | Ranges Twenty Nine [Member]
Shares underlying outstanding options
Range of exercise price	$ 2.31
Number Outstanding | shares	400,000
Weighted average remaining contractual life (years)	4 years 9 months 3 days
Weighted Average Exercise price	$ 2.31
Fully Vested [Member] | Ranges Thirty [Member]
Shares underlying outstanding options
Range of exercise price	$ 2.61
Number Outstanding | shares	481,500
Weighted average remaining contractual life (years)	2 years 8 months 5 days
Weighted Average Exercise price	$ 2.61
Fully Vested [Member] | Ranges Thirty One [Member]
Shares underlying outstanding options
Range of exercise price	$ 4.15
Number Outstanding | shares	25,000
Weighted average remaining contractual life (years)	5 years 3 months 4 days
Weighted Average Exercise price	$ 4.15
Non-vested [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	10,000
Weighted Average Exercise price	$ 0.01
Non-vested [Member] | Range One [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Range Two [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Range Three [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Range Four [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Range Five [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Range Six [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Range Seven [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Range Eight [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Range Nine [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Range Ten [Member]
Shares underlying outstanding options
Range of exercise price	$ 0.01
Number Outstanding | shares	10,000
Weighted average remaining contractual life (years)	8 years 9 months
Weighted Average Exercise price	$ 0.01
Non-vested [Member] | Range Eleven [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Range Twelve [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Thirteen [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Fourteen [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Fifteen [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Sixteen [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Seventeen [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Eighteen [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Nineteen [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Twenty [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Twenty One [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Twenty Two [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Twenty Three [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Twenty Four [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Twenty Five [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Twenty Six [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Twenty Seven [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Twenty Eight [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Twenty Nine [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
Non-vested [Member] | Ranges Thirty One [Member]
Shares underlying outstanding options
Range of exercise price
Number Outstanding | shares
Weighted Average Exercise price
[1]	27,500 are exercisable on June 30, 2019.

Stockholders' Equity (Assumptio

Stockholders' Equity (Assumptions Used to Estimate Fair Value of Warrants Granted Using Black-Scholes Option Pricing Model) (Details) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Granted to employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average fair value of underlying stock at grant date	$ 0.42	$ 2.31
Dividend yields
Expected volatility	87.00%
Risk-free interest rates	2.53%
Expected lives (in years)	5 years
Weighted-average grant date fair value	$ 0.41
Granted to employees [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility		68.00%
Risk-free interest rates		2.01%
Expected lives (in years)		3 years 6 months
Granted to employees [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility		70.00%
Risk-free interest rates		2.25%
Expected lives (in years)		5 years 6 months
Granted to non-employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average fair value of underlying stock at grant date		$ 3.37
Dividend yields
Expected volatility
Risk-free interest rates
Expected lives (in years)		10 years
Weighted-average grant date fair value		$ 3.36
Granted to non-employees [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility		73.00%
Risk-free interest rates		2.46%
Granted to non-employees [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility		76.00%
Risk-free interest rates		2.81%

Stockholders' Equity (Compensat

Stockholders' Equity (Compensation Cost of Warrant and Option Issuances Recognized) (Details) - Warrants and Options [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Employees and Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost of warrant and option issuances	$ 15	$ 943
Non-employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost of warrant and option issuances		302
Unproved Oil and Gas Properties [Member] | Employees and and Non-employees and Capitalized [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost of warrant and option issuances		$ 297

Stockholders' Equity (Schedule

Stockholders' Equity (Schedule of Warrants Description) (Details) - Investors [Member]	3 Months Ended
	Mar. 31, 2019$ / shares
ZNWAA Warrants [Member]
Class of Warrant or Right [Line Items]
Name	ZNWAA Warrants
Exercise Price	$ 2	[1]
Expiration Date	Jan. 31, 2020	[1]
ZNWAA Warrants [Member] | Beginning Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Jan. 3, 2013
ZNWAA Warrants [Member] | Ending Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Dec. 31, 2014
ZNWAD Warrants [Member]
Class of Warrant or Right [Line Items]
Name	ZNWAD Warrants	[2]
Exercise Price	$ 1	[1]
Expiration Date	May 2, 2020	[1]
ZNWAD Warrants [Member] | Beginning Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Jan. 1, 2015
ZNWAD Warrants [Member] | Ending Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Mar. 31, 2016
ZNWAE Warrants [Member]
Class of Warrant or Right [Line Items]
Name	ZNWAE Warrants
Exercise Price	$ 1	[1]
Expiration Date	May 1, 2020	[1]
ZNWAE Warrants [Member] | Beginning Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Nov. 1, 2016
ZNWAE Warrants [Member] | Ending Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Mar. 31, 2017
ZNWAF Warrants [Member]
Class of Warrant or Right [Line Items]
Name	ZNWAF Warrants	[2]
Exercise Price	$ 1	[1]
Expiration Date	Aug. 14, 2020	[1]
ZNWAF Warrants [Member] | Beginning Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	May 1, 2017
ZNWAF Warrants [Member] | Ending Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Jul. 31, 2017
ZNWAG Warrants [Member]
Class of Warrant or Right [Line Items]
Name	ZNWAG Warrants
Exercise Price	$ 1	[1]
Expiration Date	Jan. 8, 2021	[1]
ZNWAG Warrants [Member] | Beginning Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Oct. 1, 2017
ZNWAG Warrants [Member] | Ending Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Dec. 31, 2017
ZNWAH Warrants [Member]
Class of Warrant or Right [Line Items]
Name	ZNWAH Warrants	[2]
Period of Grant	Feb. 28, 2018
Exercise Price	$ 5	[1]
Expiration Date	Apr. 2, 2019	[1]
ZNWAI Warrants [Member]
Class of Warrant or Right [Line Items]
Name	ZNWAI Warrants	[2]
Exercise Price	$ 3	[1]
Expiration Date	Jun. 29, 2020	[1]
ZNWAI Warrants [Member] | Beginning Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Apr. 1, 2018
ZNWAI Warrants [Member] | Ending Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	May 31, 2018
ZNWAJ Warrants [Member]
Class of Warrant or Right [Line Items]
Name	ZNWAJ Warrants
Exercise Price	$ 1	[1]
Expiration Date	Oct. 29, 2020	[1]
ZNWAJ Warrants [Member] | Beginning Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Aug. 1, 2018
ZNWAJ Warrants [Member] | Ending Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Sep. 30, 2018
ZNWAK Warrants [Member]
Class of Warrant or Right [Line Items]
Name	ZNWAK Warrants
Exercise Price	$ 0.01	[1]
Expiration Date	Feb. 25, 2020	[1]
ZNWAK Warrants [Member] | Beginning Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Dec. 31, 2018
ZNWAK Warrants [Member] | Ending Date [Member]
Class of Warrant or Right [Line Items]
Period of Grant	Jan. 31, 2019
[1]	Zion's ZNWAB Warrants expired on May 2, 2017 and its ZNWAC Warrants expired on May 2, 2018
[2]	On December 4, 2018, the Company extended the termination date of the Warrants by one (1) year.

Stockholders' Equity (Warrants

Stockholders' Equity (Warrants Table) (Details) - Warrant Transactions [Member]	3 Months Ended
	Mar. 31, 2019$ / sharesshares
ZNWAA [Member]
Class of Warrant or Right [Line Items]
Exercise Price | $ / shares	$ 2
Warrant Termination Date	Jan. 31, 2020
Outstanding warrants, Beginning Balance	1,498,804
Warrants Issued	0
Warrants Exercised	0
Warrants Expired	0
Outstanding warrants, Ending Balance	1,498,804
ZNWAD [Member]
Class of Warrant or Right [Line Items]
Exercise Price | $ / shares	$ 1
Warrant Termination Date	May 2, 2020
Outstanding warrants, Beginning Balance	243,853
Warrants Issued	0
Warrants Exercised	0
Warrants Expired	0
Outstanding warrants, Ending Balance	243,853
ZNWAE [Member]
Class of Warrant or Right [Line Items]
Exercise Price | $ / shares	$ 1
Warrant Termination Date	May 2, 2020
Outstanding warrants, Beginning Balance	2,144,510
Warrants Issued	0
Warrants Exercised	0
Warrants Expired	0
Outstanding warrants, Ending Balance	2,144,510
ZNWAF [Member]
Class of Warrant or Right [Line Items]
Exercise Price | $ / shares	$ 1
Warrant Termination Date	Aug. 14, 2020
Outstanding warrants, Beginning Balance	359,610
Warrants Issued	0
Warrants Exercised	0
Warrants Expired	0
Outstanding warrants, Ending Balance	359,610
ZNWAG [Member]
Class of Warrant or Right [Line Items]
Exercise Price | $ / shares	$ 1
Warrant Termination Date	Jan. 8, 2021
Outstanding warrants, Beginning Balance	240,578
Warrants Issued	0
Warrants Exercised	0
Warrants Expired	0
Outstanding warrants, Ending Balance	240,578
ZNWAH [Member]
Class of Warrant or Right [Line Items]
Exercise Price | $ / shares	$ 5
Warrant Termination Date	Apr. 19, 2020
Outstanding warrants, Beginning Balance	372,400
Warrants Issued	0
Warrants Exercised	0
Warrants Expired	0
Outstanding warrants, Ending Balance	372,400
ZNWAI [Member]
Class of Warrant or Right [Line Items]
Exercise Price | $ / shares	$ 3
Warrant Termination Date	Jun. 29, 2020
Outstanding warrants, Beginning Balance	640,735
Warrants Issued	0
Warrants Exercised	0
Warrants Expired	0
Outstanding warrants, Ending Balance	640,735
ZNWAJ [Member]
Class of Warrant or Right [Line Items]
Exercise Price | $ / shares	$ 1
Warrant Termination Date	Oct. 29, 2020
Outstanding warrants, Beginning Balance	546,050
Warrants Issued	0
Warrants Exercised	0
Warrants Expired	0
Outstanding warrants, Ending Balance	546,050
ZNWAK [Member]
Class of Warrant or Right [Line Items]
Exercise Price | $ / shares	$ 0.01
Warrant Termination Date	Feb. 25, 2020
Outstanding warrants, Beginning Balance	0
Warrants Issued	673,650
Warrants Exercised	(157,605)
Warrants Expired	0
Outstanding warrants, Ending Balance	516,045

Stockholders' Equity (2011 Stoc

Stockholders' Equity (2011 Stock Option Plan) (Narrative) (Details)	3 Months Ended
	Mar. 31, 2019USD ($)$ / sharesshares
June 30, 2019 [Member]
Stockholders' Equity (Textual)
Shares purchased under option plan (in share)	27,500
2011 Equity Incentive Stock Option Plan [Member]
Stockholders' Equity (Textual)
Shares purchased under option plan (in share)	14,000
Exercise price per unit | $ / shares	$ 0.01
Fair value of stock options granted | $	$ 62,000
Stock option plan, expiration date	Apr. 5, 2028
2011 Equity Incentive Stock Option Plan [Member] | December 31, 2018 [Member]
Stockholders' Equity (Textual)
Shares purchased under option plan (in share)	17,500
2011 Non-Employee Directors Stock Option Plan [Member]
Stockholders' Equity (Textual)
Shares purchased under option plan (in share)	25,000
Exercise price per unit | $ / shares	$ 1.78
Fair value of stock options granted | $	$ 25,000
Stock option plan, expiration date	Sep. 4, 2024
23 Senior officers, staff members and consultants [Member] | 2011 Equity Incentive Stock Option Plan [Member]
Stockholders' Equity (Textual)
Shares purchased under option plan (in share)	330,000
Exercise price per unit | $ / shares	$ 0.01
Fair value of stock options granted | $	$ 759,000
Stock option plan, expiration date	Jan. 1, 2028
23 Senior officers, staff members and consultants [Member] | 2011 Equity Incentive Stock Option Plan [Member] | June 30, 2018 [Member]
Stockholders' Equity (Textual)
Shares purchased under option plan (in share)	165,000
23 Senior officers, staff members and consultants [Member] | 2011 Equity Incentive Stock Option Plan [Member] | December 31, 2018 [Member]
Stockholders' Equity (Textual)
Shares purchased under option plan (in share)	165,000
Five Senior officers [Member] | 2011 Equity Incentive Stock Option Plan [Member]
Stockholders' Equity (Textual)
Shares purchased under option plan (in share)	110,000
Exercise price per unit | $ / shares	$ 0.01
Fair value of stock options granted | $	$ 250,000
Stock option plan, expiration date	Jan. 4, 2028
Three Consultants [Member] | 2011 Equity Incentive Stock Option Plan [Member]
Stockholders' Equity (Textual)
Shares purchased under option plan (in share)	55,000
Exercise price per unit | $ / shares	$ 0.01
Fair value of stock options granted | $	$ 222,000
Stock option vested, description	The options vested upon grant. However, the exercisability of these options is according to the following schedule: (a) 27,500 options are exercisable on June 30, 2018 and (b) the remaining 27,500 options are exercisable on June 30, 2019.
Eight Board Members [Member] | 2011 Non-Employee Directors Stock Option Plan [Member]
Stockholders' Equity (Textual)
Shares purchased under option plan (in share)	400,000
Exercise price per unit | $ / shares	$ 2.31
Fair value of stock options granted | $	$ 428,000
Stock option plan, expiration date	Jan. 1, 2024

Stockholders' Equity (Warrant_2

Stockholders' Equity (Warrants and Options) (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Jan. 13, 2015
Stockholders' Equity (Textual)
Unrecognized compensation cost related to non vested stock	$ 5,000
Subscription rights offering, description	Each shareholder received .10 (one tenth) of a subscription right (i.e. one subscription right for each 10 shares owned) for each share of the Company's Common Stock owned on the Record Date.
2018 Subscription Rights Offering [Member]
Stockholders' Equity (Textual)
Subscription rights offering, description	On April 2, 2018 the Company announced an offering ("2018 Subscription Rights Offering") through American Stock Transfer & Trust Company, LLC (the "Subscription Agent"), at no cost to the shareholders, of non-transferable Subscription Rights to purchase Rights (each "Right" and collectively, the "Rights") of its securities to persons who owned shares of our Common Stock on April 13, 2018 ("the Record Date"). Pursuant to the 2018 Subscription Rights Offering, each holder of shares of common stock on the Record Date received non-transferable rights to subscribe for Rights, with each Right comprised of one share of the Company Common Stock, par value $0.01 per share (the "Common Stock") and one Common Stock Purchase Warrant to purchase an additional one share of Common Stock. Each Right may be purchased at a per Right subscription price of $5.00. Each Warrant affords the investor the opportunity to purchase one share of the Company Common Stock at a warrant exercise price of $3.00. The warrants will become exercisable on June 29, 2018 and will continue to be exercisable for one year thereafter. The warrant has the symbol "ZNWAI."
Proceeds from the sale of the rights	$ 3,038,000
Expenses from rights offering	$ 243,000
Dividend Reinvestment and Stock Purchase Plan [Member]
Stockholders' Equity (Textual)
Unit option, description	On November 1, 2016, the Company launched a unit offering (the "Unit Program") under the Company's DSPP pursuant to which participants could purchase units comprised of seven shares of Common Stock and seven Common Stock purchase warrants, at a per unit purchase price of $10.
Warrants termination, description	The warrants became exercisable on May 2, 2016 and, in the case of ZNWAB continued to be exercisable through May 2, 2017 (1 year) and, in the case of ZNWAC continued to be exercisable through May 2, 2018 for ZNWAC (2 years) and May 2, 2019 for ZNWAD (3 years), respectively, at a per share exercise price of $1.00.
Unit Option Program [Member] | ZNWAG Warrants [Member]
Stockholders' Equity (Textual)
Warrants termination, description	The warrants became exercisable on January 8, 2018 and continue to be exercisable through January 8, 2021 at a per share exercise price of $1.00. The warrant terms provide that if the Company's Common Stock trades above $5.00 per share as the closing price for 15 consecutive trading days at any time prior to the expiration date of the warrant, the Company has the sole discretion to accelerate the termination date of the warrant upon providing 60 days advanced notice to the warrant holders.
New unit program, description	The Unit Option consisted of Units of our securities where each Unit (priced at $250.00 each) was comprised of (i) 50 shares of Common Stock and (ii) Common Stock purchase warrants to purchase an additional 50 shares of Common Stock. The investor's Plan account was credited with the number of shares of the Company's Common Stock acquired under the Units purchased. Each warrant affords the investor the opportunity to purchase one share of Company Common Stock at a warrant exercise price of $5.00.
Unit Option Program [Member] | ZNWAH Warrants [Member]
Stockholders' Equity (Textual)
Warrants termination, description	The warrants became exercisable on April 2, 2018 and continue to be exercisable through April 2, 2020 at a per share exercise price of $5.00.
Unit Option Program [Member] | ZNWAJ Warrants [Member]
Stockholders' Equity (Textual)
Warrants termination, description	The warrants became exercisable on October 29, 2018 and continue to be exercisable through October 29, 2020 at a per share exercise price of $1.00, after the Company, on December 4, 2018, extended the termination date of the Warrant by one (1) year from the expiration date of October 19, 2019 to October 29, 2020.
New unit program, description	The Unit Option consisted of Units of the Company's securities where each Unit (priced at $250.00 each) was comprised of (i) a certain number of shares of Common Stock determined by dividing $250.00 (the price of one Unit) by the average of the high and low sale prices of the Company's publicly traded common stock as reported on the NASDAQ on the Unit Purchase Date and (ii) Common Stock purchase warrants to purchase an additional twenty-five (25) shares of Common Stock. The investor's Plan account was credited with the number of shares of the Company's Common Stock acquired under the Units purchased. Each warrant affords the investor the opportunity to purchase one share of Company Common Stock at a warrant exercise price of $1.00.
Warrant [Member]
Stockholders' Equity (Textual)
Amount of funds raised under the DSPP program	$ 2,528,000
Warrant [Member] | ZNWAF Warrants [Member]
Stockholders' Equity (Textual)
Exercise price per unit	$ 1
Warrants termination, description	All ZNWAF warrants became exercisable on August 14, 2017 and continue to be exercisable through August 14, 2020 at a per share exercise price of $1.00. The warrant terms provide that if the Company's Common Stock trades above $5.00 per share as the closing price for 15 consecutive trading days at any time prior to the expiration date of the warrant, the Company has the sole discretion to accelerate the termination date of the warrant upon providing 60 days advanced notice to the warrant holders.
Warrant [Member] | Dividend Reinvestment and Stock Purchase Plan [Member]
Stockholders' Equity (Textual)
Warrants termination, description	The ZNWAE warrants became exercisable on May 1, 2017 and continue to be exercisable through May 1, 2020 at a per share exercise price of $1.00. The warrant terms provide that if the Company's Common Stock trades above $5.00 per share at the closing price for 15 consecutive trading days at any time prior to the expiration date of the warrant, the Company may, in its sole discretion, accelerate the termination of the warrant upon providing 60 days advanced notice to the warrant holders.
Warrant [Member] | New Unit Program [Member]
Stockholders' Equity (Textual)
Purchase warrants unit price		$ 4
Exercise price per unit		$ 1
New unit program, description	This New Unit Program enabled participants to purchase Units of the Company's securities where each Unit (priced at $250.00 each) was comprised of (i) the number of shares of Common Stock determined by dividing $250.00 (the price of one Unit) by the average of the high and low sale prices of the Company's Common Stock as reported on the NASDAQ on the unit purchase date and (ii) Common Stock purchase warrants to purchase an additional 25 shares of Common Stock at a warrant exercise price of $1.00 per share.
Warrant [Member] | Unit Option Program [Member]
Stockholders' Equity (Textual)
Purchase warrants unit price	$ 1
New unit program, description	This Unit Option Program enabled participants to purchase Units of the Company's securities where each Unit (priced at $250.00 each) was comprised of (i) a certain number of shares of Common Stock determined by dividing $250.00 (the price of one Unit) by the average of the high and low sale prices of the Company's Common Stock as reported on the NASDAQ on the unit purchase date and (ii) Common Stock purchase warrants to purchase an additional 15 shares of Common Stock at a warrant exercise price of $1.00 per share.

Unproved Oil and Gas Properti_3

Unproved Oil and Gas Properties, Full Cost Method (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Excluded from amortization base:
Drilling costs, and other operational related costs	$ 1,242		$ 1,242
Capitalized salary costs	1,625		1,579
Capitalized interest costs	687		677
Legal costs, license fees and other preparation costs	3,344		3,216
Other costs	2
Total unproved oil and gas properties, full cost method	6,900		$ 6,714
Unproved Oil and Gas Properties [Member]
Excluded from amortization base:
Drilling costs, and other operational related costs	142
Other costs	21
Total unproved oil and gas properties, full cost method	$ 163

Unproved Oil and Gas Properti_4

Unproved Oil and Gas Properties, Full Cost Method (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Excluded from amortization base:
Drilling costs, and other operational related costs		$ 3,466
Capitalized salary costs	46	337
Capitalized interest costs	10	86
Legal costs, license fees and other preparation costs	128	278
Other costs	2	72
Changes in Unproved oil and gas properties	$ 186	$ 4,239

Unproved Oil and Gas Properti_5

Unproved Oil and Gas Properties, Full Cost Method (Details Textual)	Mar. 31, 2019USD ($)
Unproved Oil and Gas Properties, Full Cost Method (Textual)
Unproved oil and gas properties unpaid amount	$ 587,000

Senior Convertible Bonds (Detai

Senior Convertible Bonds (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Senior Convertible Bonds [Abstract]
10% Senior Convertible Bonds, on the day of issuance	$ 3,470	$ 3,470
Unamortized Debt discount, net	(900)	(993)
Bonds converted to shares	(204)	(203)
Offering cost, net	(57)	(63)
10% senior Convertible bonds - Long Term Liability	$ 2,309	$ 2,211

Senior Convertible Bonds (Narra

Senior Convertible Bonds (Narrative) (Details)	May 02, 2016USD ($)	Oct. 21, 2015$ / shares	Mar. 31, 2019USD ($)Bonds$ / sharesshares	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)	May 02, 2018
Senior Convertible Bonds (Textual)
Interest expense			$ 71,000	$ 0
Convertible bonds			3,470,000		$ 3,470,000
Principal amount			3,265,700		3,266,700
Unamortized Debt discount, net			$ (900,000)		$ (993,000)
Average Company stock price | $ / shares			$ 0.774
Stock issued to bondholders | shares			422,248
Debt discount on derivative liability			$ 1,626,000
Rights offering [Member]
Senior Convertible Bonds (Textual)
Debt instrument, maturity date		May 2, 2021
Convertible bonds purchase price | $ / shares		$ 100
Senior unsecured notes interest rate		10.00%
Debt conversion, description			Under the rights offering, the Company distributed at no cost, 360,000 non-transferable subscription rights to subscribe for, on a per right basis, two 10% Convertible Senior Bonds par $100 due May 2, 2021 (the "Notes"), to shareholders of the Company's Common Stock on October 15, 2015, the record date for the offering. Each whole subscription right entitled the participant to purchase two convertible bonds at a purchase price of $100 per bond.
Principal amount	$ 3,470,000
Expenses from rights offering	136,000
Net proceeds from sale of the Notes	$ 3,334,000
10% Senior Convertible Bonds [Member]
Senior Convertible Bonds (Textual)
Debt instrument, maturity date			May 2, 2021
Debt instrument payment description			Payable annually in arrears on May 2 of each year, commencing May 2, 2017.
Senior unsecured notes interest rate			10.00%			10.00%
Debt conversion, description			At any time prior to the close of business on the business day immediately preceding April 2, 2021, holders may convert their notes into Common Stock at the conversion rate of 44 shares per $100 bond (which is equivalent to a conversion rate of approximately $2.27 per share).
Amortization expense			$ 6,000
Convertible bonds			1,844,000
Principal amount			3,470,000
Unamortized Debt discount, net			93,000
Financing costs associated notes converted to shares			$ 1,000
10% Senior Convertible Bonds [Member] | Rights offering [Member]
Senior Convertible Bonds (Textual)
Debt instrument, maturity date			May 2, 2021
Debt instrument payment description			The number of shares for the payment of interest in shares of Common Stock, in lieu of the cash amount, will be based on the average of the closing prices of the Company's Common Stock as reported by Bloomberg L.P. for the 30 trading days preceding the record date for the payment of interest; such record date has been designated and will always be the 10th business day prior to the interest payment date on May 2 of each year. The number of shares for the payment of principal, in lieu of the cash amount, shall be based upon the average of the closing price of the Company's Common Stock as reported by Bloomberg L.P. for the 30 trading days preceding the principal repayment date; such record date has been designated as the trading day immediately prior to the 30-day period preceding the maturity date of May 2, 2021.
Description of note redeemption			The Company was entitled to redeem for cash the outstanding Notes at an amount equal to the principal and accrued and unpaid interest, plus a 10% premium.
Senior unsecured notes interest rate						10.00%
10% Senior Convertible Bonds [Member] | Debt issuance [Member]
Senior Convertible Bonds (Textual)
Debt instrument payment description			The interest was paid-in-kind ("PIK") in the form of Common Stock. An average of the Company stock price of $4.68 was determined based on the 30 trading days prior to the record date of April 18, 2018. This figure was used to divide into 10% of the par value of the bonds held by the holders.
10% Senior Convertible Bonds [Member] | Debt issuance [Member] | Rights offering [Member]
Senior Convertible Bonds (Textual)
Convertible bonds purchase price | $ / shares			$ 2.27
Interest expense			$ 10,000	$ 86,000
Number of convertible bonds | Bonds			10
Convertible bond price			$ 100
Common stock issued | shares			440
Financial expenses			$ (1,000)

Derivative Liability (Details)

Derivative Liability (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Fair value of derivative liability	$ 723	$ 345
Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Fair value of derivative liability	$ 723	$ 345

Derivative Liability (Details 1

Derivative Liability (Details 1) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Derivative Liability [Abstract]
Derivative liability fair value, beginning balance	$ 345
Loss on derivative liability	378
Derivative liability fair value, ending balance	$ 723

Derivative Liability (Details 2

Derivative Liability (Details 2) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Derivative Liability [Abstract]
Convertible Option Fair Value of approximately	$ 723,000	$ 345,000
Annual Risk-free Rate	2.27%	2.47%
Volatility	123.19%	115.35%
Expected Term (years)	2 years 1 month 2 days	2 years 4 months 2 days
Convertible Notes Face Value	$ 3,265,700	$ 3,266,700
Expected annual yield on Regular Notes	28.77%	28.77%
Price of the Underlying Stock	$ 0.76	$ 0.42

Derivative Liability (Narrative

Derivative Liability (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Derivative Liability (Textual)
Loss on derivative liability	$ 378

Right of Use Leases Assets an_3

Right of Use Leases Assets and Leases Obligations (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease assets	$ 730
Operating lease liabilities:
Current operating lease liabilities	210
Non-current operating lease liabilities	564
Total operating lease liabilities	$ 774

Right of Use Leases Assets an_4

Right of Use Leases Assets and Leases Obligations (Details 1)	Mar. 31, 2019
Leases [Abstract]
Weighted average remaining lease term (years)	3 years 9 months 18 days
Weighted average discount rate	6.00%

Right of Use Leases Assets an_5

Right of Use Leases Assets and Leases Obligations (Details 2) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Operating Lease Liabilities, Payments Due [Abstract]
April 1, 2019 through December 31, 2019	$ 271
2020	271
2021	156
2022	134
2023	112
Thereafter
Total undiscounted future minimum lease payments	944
Less: portion representing imputed interest	(170)
Total undiscounted future minimum lease payments	$ 774

Right of Use Leases Assets an_6

Right of Use Leases Assets and Leases Obligations (Narrative) (Details)	3 Months Ended
	Mar. 31, 2019USD ($)
Right Of Use Leases Assets And Leases Obligations Textual [Abstract]
Operating lease costs	$ 68,000
Operating lease liabilities	71,000
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 824,000

Commitments and Contingencies (

Commitments and Contingencies (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Commitments and Contingencies (Textual)
Bank guarantees to government bodies	$ 1,009,000
Bank guarantees to others	82,000
Aggregate guarantee amount	1,091,000
Advanced deposit	500,000
Restricted cash	$ 3,135,000	$ 4,125,000	$ 6,345,000	$ 9,079,000
Cash and cash equivalents weighted average interest rate	0.13%
Foreign currency exchange rate risks, description	During the period January 1, 2019 through March 31, 2019, the USD has fluctuated by approximately (3.1%) against the NIS (the USD has weakened relative to the NIS). By contrast, during the period January 1, 2018 through December 31, 2018, the USD fluctuated by approximately 8.1% against the NIS (the USD strengthened relative to the NIS). Continued weakening of the US dollar against the NIS will result in higher operating costs from NIS denominated expenses. To date, we have not hedged any of our currency exchange rate risks, but we may do so in the future.

Subsequent Events (Narrative) (

Subsequent Events (Narrative) (Details) - Subsequent Event [Member] - USD ($)	May 01, 2019	Apr. 30, 2019
Subsequent Events (Textual)
Amount collected from DSPP		$ 504,000
Subsequent Event, Description	Options to purchase 100,000 shares of Common Stock were granted to one senior office at an exercise price of $0.01 per share. The options are exercisable through May 1, 2029. However, the vesting and exercisability of these options is subject to the following schedule: (a) 50,000 options vest on September 1, 2019 and (b) the remaining 50,000 options vest on January 1, 2020. The fair value of the options at the date of grant amounted to $55,000.