Stockholders' Equity (Tables)

6 Months Ended

Jun. 30, 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 *		125,000			0.01
Expired/Cancelled/Forfeited		(385,693	)		2.07
Exercised		(52,500	)		0.01
Outstanding, June 30, 2019		4,475,250			1.29
Exercisable, June 30, 2019		4,375,250			1.32

* 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		4.37		0.01
	—		—		—		—		0.01		15,000		4.76		0.01
	—		—		—		—		0.01		5,000		4.95		0.01
	—		—		—		—		0.01		10,000		6.26		0.01
	—		—		—		—		0.01		25,000		6.50		0.01
	—		—		—		—		0.01		305,000		6.93		0.01
	—		—		—		—		0.01		525,000		7.50		0.01
	—		—		—		—		0.01		10,000		7.51		0.01
	—		—		—		—		0.01		60,000		7.79		0.01
	0.01		100,000		9.83		0.01		0.01		40,000		8.25		0.01
	—		—		—		—		0.01		180,000		8.50		0.01
	—		—		—		—		0.01		85,000		8.51		0.01
	—		—		—		—		0.01		45,000		8.66		0.01
	—		—		—		—		0.01		6,000		8.77		0.01
	—		—		—		—		0.01		25,000		9.52		0.01
	—		—		—		—		1.33		25,000		3.83		1.33
	—		—		—		—		1.38		108,000		1.51		1.38
	—		—		—		—		1.38		105,307		5.52		1.38
	—		—		—		—		1.55		400,000		2.93		1.55
	—		—		—		—		1.67		340,000		1.26		1.67
	—		—		—		—		1.67		405,943		5.26		1.67
	—		—		—		—		1.70		218,500		3.48		1.70
	—		—		—		—		1.75		400,000		4.02		1.75
	—		—		—		—		1.78		25,000		5.19		1.78
	—		—		—		—		1.87		25,000		2.59		1.87
	—		—		—		—		1.95		25,000		0.76		1.95
	—		—		—		—		1.96		25,000		0.18		1.96
	—		—		—		—		2.03		25,000		1.84		2.03
	—		—		—		—		2.31		400,000		4.51		2.31
									2.61		471,500		2.43		2.61
	—		—		—		—		4.15		25,000		5.01		4.15
	0.01		100,000				0.01		0.01-4.15		4,375,250				1.32

Schedule of compensation cost of 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 six months ended June 30,
2019		2018
US$ thousands		US$ thousands
	40		1,279

The following table sets forth information about the compensation cost of warrant and option issuances recognized for non-employees:

For the six months ended June 30,
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 six months ended June 30,
2019		2018
US$ thousands		US$ thousands
	—		328

Schedule of warrants description

		Period of Grant	US$		Expiration Date
ZNWAA Warrants	B	March 2013 – December 2014		2.00	January 31, 2021
ZNWAD Warrants	A,B	January 2015 – March 2016		1.00	May 02, 2021
ZNWAE Warrants	B	November 2016 – March 2017		1.00	May 01, 2021
ZNWAF Warrants	A,B	May 2017 – July 2017		1.00	August 14, 2021
ZNWAG Warrants		October 2017 – December 2017		1.00	January 08, 2021
ZNWAH Warrants	A,B	February 2018		5.00	April 2, 2021
ZNWAI Warrants	A,B	April 2018 – May 2018		3.00	June 29, 2021
ZNWAJ Warrants	B	August 2018 – September 2018		1.00	October 29, 2021
ZNWAK Warrants	B	December 2018 – January 2019		0.01	February 25, 2021
ZNWAL Warrants		July 2019 – August 2019		2.00	August 26, 2021

*	Zion's ZNWAB Warrants expired on May 2, 2017, and the ZNWAC Warrants expired on May 2, 2018
A	On December 4, 2018, the Company extended the termination date of the Warrants by one (1) year.
B	On May 29, 2019, the Company extended the termination date of the Warrants by one (1) year.

Non Employee [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 six months ended June 30,
	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

Employee [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 six months ended June 30,
	2019			2018
Weighted-average fair value of underlying stock at grant date	$	0.53		$	2.34
Dividend yields		—			—
Expected volatility		87%-88	%		68%-75	%
Risk-free interest rates		2.31%-2.53	%		2.01%-2.58	%
Expected lives (in years)		5.00-5.34			3.00-5.50
Weighted-average grant date fair value	$	0.52		$	1.73

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	Outstanding Balance, 12/31/18		Warrants Issued		Warrants Exercised			Warrants Expired		Outstanding Balance, 6/30/19
ZNWAA	$	2.00	1/31/2021		1,498,804		0		0			0		1,498,804
ZNWAD	$	1.00	5/2/2021		243,853		0		0			0		243,853
ZNWAE	$	1.00	5/2/2021		2,144,510		0		(40	)		0		2,144,470
ZNWAF	$	1.00	8/14/2021		359,610		0		0			0		359,610
ZNWAG	$	1.00	1/8/2021		240,578		0		0			0		240,578
ZNWAH	$	5.00	4/19/2021		372,400		0		0			0		372,400
ZNWAI	$	3.00	6/29/2021		640,735		0		(5	)		0		640,730
ZNWAJ	$	1.00	10/29/2021		546,050		0		(25	)		0		546,025
ZNWAK	$	0.01	2/25/2021		0		673,600		(199,500	)		0		474,100
Outstanding warrants					6,046,540		673,600		(199,570	)		0		6,520,570