Vista Gold (VGZ) 10-Q 29 Oct 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 22, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	VISTA GOLD CORP
Entity Central Index Key	783,324
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Entity Common Stock, Shares Outstanding		100,145,811
Entity Current Reporting Status	Yes
Entity Small Business	false
Entity Emerging Growth Company	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 1,163	$ 1,431
Short-term investments (Note 3)	9,029	15,144
Other investments, at fair value (Note 3)	5,500	3,746
Other current assets	227	794
Total current assets	15,919	21,115
Non-current assets:
Mineral properties (Note 4)	2,471	2,471
Plant and equipment, net (Note 5)	7,389	7,555
Total non-current assets	9,860	10,026
Total assets	25,779	31,141
Current liabilities:
Accounts payable	217	830
Accrued liabilities and other	493	986
Provision for environmental liability	242	242
Total current liabilities	952	2,058
Total liabilities	952	2,058
Commitments and contingencies – (Note 7)
Shareholders' equity:
Common shares, no par value - unlimited shares authorized; shares outstanding: 2018 - 100,089,561 and 2017 - 99,412,007 (Note 6)	456,730	456,053
Accumulated other comprehensive loss		(2)
Accumulated deficit	(431,903)	(426,968)
Total shareholders' equity	24,827	29,083
Total liabilities and shareholders' equity	$ 25,779	$ 31,141

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Shareholders' equity:
Common Shares, par value	$ 0	$ 0
Common shares outstanding	100,089,561	99,412,007

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) [Abstract]
Revenues			$ 0	$ 0
Operating expense:
Exploration, property evaluation and holding costs	$ (960)	$ (1,635)	$ (3,560)	$ (4,695)
Type of Cost, Good or Service [Extensible List]			us-gaap:MineralExplorationMember	us-gaap:MineralExplorationMember
Corporate administration	(969)	(823)	$ (3,280)	$ (2,619)
Depreciation and amortization	(12)	(137)	(252)	(455)
Gain on disposal of mineral property, net (Note 4)				358
Total operating expense	(1,941)	(2,595)	(7,092)	(7,411)
Non-operating income/(expenses):
(Loss)/gain on other investments (Note 3)	(274)	(78)	1,754	(858)
Interest income	72	38	322	117
Other income/(expense)	81	(20)	83	(32)
Total non-operating income/(expense)	(121)	(60)	2,159	(773)
Net loss	(2,062)	(2,655)	(4,933)	(8,184)
Other comprehensive loss:
Unrealized fair value increase/ (decrease) on available-for-sale securities		1		(20)
Comprehensive loss	$ (2,062)	$ (2,654)	$ (4,933)	$ (8,204)
Basic:
Weighted average number of shares outstanding (in shares)	99,805,266	98,993,395	99,600,267	98,363,761
Net loss per share, Basic (in dollars per share)	$ (0.02)	$ (0.03)	$ (0.05)	$ (0.08)
Diluted:
Weighted average number of shares outstanding (in shares)	99,805,266	98,993,395	99,600,267	98,363,761
Net loss per share, Diluted (in dollars per share)	$ (0.02)	$ (0.03)	$ (0.05)	$ (0.08)

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Previously Reported [Member]Common Stock [Member]	Previously Reported [Member]Accumulated Deficit [Member]	Previously Reported [Member]Accumulated Other Comprehensive Income/(Loss) [Member]	Previously Reported [Member]	Common Stock [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Total
Balances, beginning of period at Dec. 31, 2016					$ 455,443	$ (414,933)	$ 15	$ 40,525
Balances, beginning of period (in shares) at Dec. 31, 2016					97,786,608
Shares issued (RSUs vested, net of shares withheld)					$ (264)			(264)
Shares issued (RSUs vested, net of shares withheld) (in shares)					1,625,399
Stock-based compensation					$ 874			874
Other comprehensive loss							(17)	(17)
Net loss						(12,035)		(12,035)
Balances, end of period at Dec. 31, 2017	$ 456,053	$ (426,968)	$ (2)	$ 29,083	$ 456,053	(426,970)		29,083
Balances, end of period (in shares) at Dec. 31, 2017	99,412,007				99,412,007
Cumulative adjustment related to Accounting Standard Update 2016-01 | Accounting Standards Update 2016-01 [Member]						(2)	$ 2
Shares issued (RSUs vested, net of shares withheld)					$ (122)			(122)
Shares issued (RSUs vested, net of shares withheld) (in shares)					637,554
Shares issued (exercise of stock options)					$ 16			$ 16
Shares issued (exercise of stock options) (in shares)					40,000			40,000
Stock-based compensation					$ 855			$ 855
Option amendment (Note 6)					(72)			(72)
Net loss						(4,933)		(4,933)
Balances, end of period at Sep. 30, 2018					$ 456,730	$ (431,903)		$ 24,827
Balances, end of period (in shares) at Sep. 30, 2018					100,089,561

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Cash flows from operating activities:
Net loss for the period			$ (4,933)	$ (8,184)
Adjustments to reconcile net loss for the period to net cash used in operations:
Depreciation and amortization	$ 12	$ 137	252	455
Stock-based compensation			855	680
Gain on disposal of mineral property				(358)
(Gain)/loss on other investments	274	78	(1,754)	858
Change in working capital account items:
Other current assets			411	104
Accounts payable, accrued liabilities and other			(1,178)	378
Net cash used in operating activities			(6,347)	(6,067)
Cash flows from investing activities:
Proceeds from sales of marketable securities			156
Disposition of short-term investments, net of acquisitions			6,115	5,317
Additions to plant and equipment			(86)
Proceeds from option/sales agreements, net				358
Net cash provided by investing activities			6,185	5,675
Cash flows from financing activities:
Payment of taxes from withheld shares			(122)	(264)
Proceeds from exercise of stock options			16
Net cash used in financing activities			(106)	(264)
Net decrease in cash and cash equivalents			(268)	(656)
Cash and cash equivalents, beginning of period			1,431	1,904	$ 1,904
Cash and cash equivalents, end of period	$ 1,163	$ 1,248	$ 1,163	$ 1,248	$ 1,431

Nature of Operations and Basis

Nature of Operations and Basis of Presentation	9 Months Ended
	Sep. 30, 2018
Nature of Operations and Basis of Presentation
Nature of Operations and Basis of Presentation	1. Nature of Operations and Basis Vista Gold Corp. and its subsidiaries (collectively, “Vista,” the “Company,” “we,” “our,” or “us”) operate in the gold mining industry. We are focused on the evaluation, acquisition, exploration and advancement of gold exploration, and potential development projects, which may lead to gold production or value adding strategic transactions such as earn-in right agreements, option agreements, leases to third parties, joint venture arrangements with other mining companies, or outright sales of assets for cash and/or other consideration. We look for opportunities to improve the value of our gold projects through exploration drilling and/or technical studies focused on optimizing previous engineering work. The Company’s flagship asset is its 100% owned Mt Todd gold project (“Mt Todd”) in the Northern Territory (“NT”) Australia. Mt Todd is the largest undeveloped gold project in Australia. In January 2018, the Company received authorization for the last major environmental permit and we announced the positive results of an updated preliminary feasibility study (the “PFS”) for Mt Todd. Subsequently, Vista has completed additional metallurgical testing, including ongoing fine grinding evaluations, which demonstrate further improvements in gold recovery. With these important milestones and subsequent project improvements complete, Vista is in a better position to identify and pursue those strategic alternatives that may provide the best opportunity for shareholders to realize fair value for Mt Todd. We also hold 7.8 million shares of the outstanding common shares in the capital of Midas Gold Corp. (“Midas Gold Shares”), a non-core project in Mexico and royalty interests in the United States and Indonesia. The interim Condensed Consolidated Financial Statements (“interim statements”) of the Company are unaudited. In the opinion of management, all adjustments and disclosures necessary for a fair presentation of these interim statements have been included. The results reported in these interim statements are not necessarily indicative of the results that may be reported for the entire year. These interim statements should be read in conjunction with the Company’s Consolidated Financial Statements for the year ended December 31, 2017 as filed with the United States Securities and Exchange Commission and Canadian securities regulatory authorities on March 6, 2018 on Form 10-K. The year-end balance sheet data was derived from the audited financial statements and, in accordance with the instructions to Form 10-Q, certain information and footnote disclosures required by United States generally accepted accounting principles have been condensed or omitted. References to A$ are to Australian currency and $ are to United States currency.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Significant Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Accounting Policies Revenue Recognition New FASB guidance issued under ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), as amended, is effective for interim and annual periods beginning after December 15, 2017. Under ASU No. 2014-09, an entity should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU No. 2014-09 also requires additional disclosure about the nature, amount, timing, and uncertainty of revenue and cash flows arising from customer contracts. This includes significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. Effective January 1, 2018, the Company adopted the new guidance retrospectively. The Company performed an assessment of the revised guidance and the impacts on the Company’s Consolidated Financial Statements and disclosures. We also evaluated the potential for future variable consideration from option payments, net smelter return royalties (“NSR”), and other production related payments, and determined that there is no impact to the Company’s current accounting. The Company determined that the adoption of this guidance will primarily impact the timing of revenue recognition on certain option agreements based on the Company’s determination of when control is transferred for accounting purposes. Based on the contracts outstanding as of December 31, 2017, there was no cumulative effect adjustment required to be recognized at January 1, 2018. Under the Company’s adoption approach, results for reporting periods beginning after January 1, 2018, will be presented in the Consolidated Financial Statements under the new guidance, while prior period amounts will not be adjusted and continue to be reported under the guidance in effect for those periods. Currently, proceeds received from option agreements are ascribed to recovery of the carrying value of the related project until the carrying value reaches zero. After that, any additional proceeds received will be recognized as a contract liability until control has transferred to the buyer or the related contract has terminated. None of the projects which could provide the Company with future variable consideration are currently in production, and in all cases, we believe there is low probability of future production from these projects. Accordingly, the Company believes its NSRs and other production related payments are fully constrained, and the Company did not record a receivable for them. When it becomes probable that a project which could provide the Company with an NSR or other production related payments could begin production, the Company will evaluate the accounting treatment at that time. Lease Accounting In February 2016 the FASB issued ASU No. 2016-02, Leases. The new standard establishes a right-of-use (“ROU”) model that requires a lessee to record an ROU asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. The new standard is effective for interim and annual periods beginning after December 15, 2018. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. Based upon our initial review, we expect to recognize additional operating liabilities of approximately $125 to $225 on adoption, with corresponding ROU assets of the same amount, based on the present value of the remaining lease payments. Nonemployee Share-Based Payments The FASB issued ASU No. 2018-07, Compensation - Stock Compensation (Topic 718) - Improvements to Nonemployee Share-Based Payment Accounting. ASU No. 2018-07, supersedes the guidance for equity-based payments to non-employees (Topic ASC 505-50). Under the new standard, an entity should treat equity-based payments to nonemployees the same as stock-based compensation to employees in most cases. The new guidance is effective for interim and annual periods beginning after December 15, 2018, with early adoption permitted. Effective July 1, 2018, the Company adopted the new guidance. The Company performed an assessment of the standard and the impacts on the Company’s Consolidated Financial Statements and disclosures. Based on our analysis, adoption of the standard will not materially change the Company’s expense recognition and disclosures.

Short-term and Other Investment

Short-term and Other Investments	9 Months Ended
	Sep. 30, 2018
Short-term and Other Investments [Abstract]
Short-term and Other Investments	3. Short-term and Other Investments Short-term investments As of September 30, 2018 and December 31, 2017, the amortized cost basis of our short-term investments was $9,029 and $15,144, respectively. The amortized cost basis approximates fair value at September 30, 2018 and December 31, 2017. Short-term investments at September 30 , 2018 and December 31, 2017 are comprised of U.S. government treasury bills and/or notes, all of which have maturity dates on the date of purchase greater than 90 days but less than one year. Other investments - Midas Gold Shares Upon initial recognition of our investment in the Midas Gold Shares, we elected to apply the fair value option, and as such, the investment in Midas Gold Shares is recorded at fair value in the Condensed Consolidated Balance Sheets. Subsequent changes in fair value are recorded in the Condensed Consolidated Statements of Comprehensive Income/(Loss) in the period in which they occur. The following table summarizes our investment in Midas Gold Shares as of September 30, 2018 and December 31, 2017. September 30, 2018 December 31, 2017 Fair value at beginning of period $ 3,746 $ 4,994 Gain/(loss) during the period 1,754 (1,248) Fair value at end of period $ 5,500 $ 3,746 Midas Gold Shares held at the end of the period 7,802,615 7,802,615

Mineral Properties

Mineral Properties	9 Months Ended
	Sep. 30, 2018
Mineral Properties [Abstract]
Mineral Properties	4. Mineral Properties At September 30, 2018 At December 31, 2017 Mt Todd, Australia $ 2,146 $ 2,146 Guadalupe de los Reyes, Mexico 325 325 $ 2,471 $ 2,471 During October 2017, we entered into an agreement (the “Option Agreement”) to option our interest in the Guadalupe de los Reyes gold and silver project in Sinaloa, Mexico (the “GdlR Project”) to Minera Alamos Inc. and its subsidiary Minera Alamos de Sonora S.A. de C.V. (“Minera Alamos”). Pursuant to the terms of the Option Agreement, we granted Minera Alamos an exclusive right and option right to earn a 100% interest in the GdlR Project by: · making payments totaling $6,000 comprised of a payment of $1,500 made at the execution of the Option Agreement (“Option Grant Date”); two successive payments of $1,500 each to be made at the one-year and two-year anniversaries of the Option Grant Date; and a final $1,500 payment to be made before the four-year anniversary of the Option Grant Date; · maintaining the concessions comprising the GdlR Project in good standing; · fulfilling all of our obligations to the Ejido La Tasajera (the “Ejido”) as set out in the temporary occupation contract between us and the Ejido; · granting us a capped NSR on production from open pit mining (the “Open Pit NSR”) at rates that range from 1% (at gold prices of $1,400/oz or less) to a maximum of 2% (at gold prices above $1,600/oz) up to an aggregate of $2,000 in royalty payments; · granting us a perpetual NSR on production from underground mining (the “Underground NSR”) at rates that range from 1% (at gold prices of $1,400/oz or less) to a maximum of 2% (at gold prices above $1,600/oz); and · granting us the right to assume a 49% non-carried interest in an underground project if Minera Alamos decides to develop an underground mine at the GdlR Project (the “Back-in Right”). The Option Agreement provides that all cash payments are non-refundable and optional to Minera Alamos, and in the event Minera Alamos fails to pay any of the required amounts as set out in the Option Agreement, or fails to comply with its other obligations, the Option Agreement will terminate and Minera Alamos will have no interest in the GdlR Project. Provided it is not in breach of the Option Agreement, Minera Alamos may at its discretion advance the above payment schedule. Subject to Minera Alamos timely making all the option payments, and fulfilling its other obligations with respect to the Option Agreement, we will transfer 100% of the shares of the Company’s 100% owned subsidiary Minera Gold Stake S.A. de C.V., the entity which owns the GdlR Project, to Minera Alamos and the Open-Pit NSR and Underground NSR will be granted to us. If Minera Alamos discovers, and decides to develop, an underground mine at the GdlR Project and we exercise the Back-in Right, we and Minera Alamos have agreed to form a joint venture to develop and operate the underground mine. If the joint venture is formed, the Underground NSR will terminate. The Company has determined that control of the GdlR Project has not been transferred for accounting purposes. The first option payment of $1,500 received in October 2017 has been accounted for as reduction to carrying value. Subsequent option payments received, if any, will be accounted for as further reductions to carrying value. After the carrying value has been reduced to zero, remaining option payment proceeds, if any, will be recognized as a contract liability until control of the GdlR Project has transferred to the buyer or the Option Agreement has been terminated. In addition, in accordance with our policy, potential royalty revenue and future option payments have been fully constrained. See also Note 10. Long Valley Claims During the three months ended March 31, 2017, we sold our Long Valley unpatented mining claims located in California for consideration, net of transaction costs, of $358 which was paid at closing; a future payment of $500 one month after the start of commercial production; a future payment of $500 on or prior to the first anniversary of the start of commercial production; and a NSR on any future production from said claims at a variable rate between 0.5% and 2.0% depending on the average gold price realized . This NSR is fully constrained. The Company has determined that control of the Long Valley claims were transferred to the buyer at the time of sale for accounting purposes. This sale resulted in a realized gain of $358.

Plant And Equipment

Plant And Equipment	9 Months Ended
	Sep. 30, 2018
Plant And Equipment [Abstract]
Plant And Equipment	5. Plant and Equipment September 30, 2018 December 31, 2017 Accumulated Accumulated Cost depreciation Net Cost depreciation Net Mt Todd, Australia $ 5,719 $ 4,830 $ 889 $ 5,646 $ 4,591 $ 1,055 Corporate, United States 333 333 — 333 333 — Used mill equipment, Canada 6,500 — 6,500 6,500 — 6,500 $ 12,552 $ 5,163 $ 7,389 $ 12,479 $ 4,924 $ 7,555

Common Shares

Common Shares	9 Months Ended
	Sep. 30, 2018
Capital Stock [Abstract]
Common Shares	6. Common Shares Warrants Warrant activity is summarized in the following table: Weighted Weighted average average Warrants exercise price remaining life outstanding per share (yrs.) Intrinsic value As of December 31, 2017 6,514,625 $ 1.92 1.6 $ — As of September 30, 2018 6,514,625 $ 1.92 0.9 $ — Stock-Based Compensation Under the Company’s stock option plan (the “Plan”), we may grant options to purchase common shares of the Company (“Common Shares”) to our directors, officers, employees and consultants. The maximum number of our Common Shares that may be reserved for issuance under the Plan, together with RSUs currently outstanding under the LTIP, is a variable number equal to 10% of the issued and outstanding Common Shares on a non-diluted basis at any one time. Options under the Plan are granted from time to time at the discretion of the Board, with vesting periods and other terms as determined by the Board. Stock-based compensation expense for the three and nine months ended September 30, 2018 and 2017 is as follows: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Stock options $ 107 $ 8 $ 307 $ 32 Restricted stock units 164 245 548 648 $ 271 $ 253 $ 855 $ 680 Phantom units (Discussed below) 11 — 11 — As of September 30, 2018, stock options, RSUs, and phantom units had unrecognized compensation expense of $223, $324, and $122 respectively, which is expected to be recognized over a weighted average period of 1.2, 0.9, and 1.8 years, respectively. Stock Options A summary of options under the Plan as of September 30, 2018 is set forth in the following table: Weighted average Weighted average Aggregate Number of exercise price remaining intrinsic options per option contractual term value Outstanding - December 31, 2017 1,144,500 $ 0.42 1.15 $ 346 Granted 1,142,000 0.71 Exercised (40,000) 0.40 Outstanding - September 30, 2018 2,246,500 $ 0.57 2.51 $ 130 Exercisable - September 30, 2018 1,240,581 $ 0.52 1.71 $ 94 A summary of our unvested stock options as of September 30, 2018 is set forth in the following table: Weighted Weighted average average remaining grant-date amortization Number of fair value period options per option (Years) Unvested - December 31, 2017 246,250 $ 0.22 0.99 Granted 1,142,000 0.45 Vested (382,331) 0.45 Unvested - September 30, 2018 1,005,919 $ 0.39 1.24 No stock options were granted for the nine months ended September 30, 2017. The fair value of stock options granted during the nine months ended September 30, 2018 to employees, directors and consultants was estimated at the grant date using the Black-Scholes option pricing model using the following assumptions: 2018 Expected volatility 76.2 % Risk-free interest rate 2.7 % Expected life (years) 5 Dividend yield — Forfeiture assumption — % Option Amendment In July 2018, the Company amended certain 2013 stock option agreements, expiring December 30, 2018 subject to the potential for a temporary extension under the terms of the Plan, for seven executives and directors (the “Option Amendment”). The amendment provides each grantee the opportunity to receive a cash buyout of certain vested, unexercised 2013 options in lieu of exercising the option to purchase shares. This cash buyout is based on the intrinsic value of each option at the time of the buyout. As a result of this modification, the Company will account for these options as awards classified as liabilities with $72 included in current liabilities. The options were previously accounted for as awards classified as equity. The Company recognized no additional compensation expense for these options in the nine months ended September 30, 2018. Restricted Stock Units The following table summarizes the RSUs outstanding under the LTIP as of September 30, 2018: Weighted average Number grant-date fair of RSUs value per RSU Unvested - December 31, 2017 1,567,907 $ 0.85 Cancelled/forfeited (246,683) 0.90 Vested, net of shares withheld (637,554) 0.88 Granted 319,000 0.75 Unvested - September 30, 2018 1,002,670 $ 0.78 A portion of the RSU awards vest on a fixed future date provided the recipient continues to be affiliated with Vista on that date. Other RSU awards vest subject to certain performance and market criteria, including the accomplishment of certain corporate objectives and the Company’s share price performance. The minimum vesting period for RSUs is one year. During the nine months ended September 30, 2018, the Company withheld shares with an equivalent value to meet the employee withholding tax obligations which resulted from RSUs that vested in the period. Shares withheld are considered cancelled/forfeited. New RSUs will not be granted under the LTIP until the allocation of such awards is duly approved by the shareholders of the Company. Phantom Units Weighted average Number of remaining phantom units contractual term Unvested - December 31, 2017 — Granted 265,000 Unvested - September 30, 2018 265,000 1.75 The Company granted a total of 265,000 phantom units to certain employees during the nine months ended September 30, 2018. The value of each unit is equal to the Company’s share price on the vesting date and is payable in cash. The phantom units vest on fixed future dates provided the recipient continues to be affiliated with Vista on those dates. The company will account for these units as awards classified as liabilities with $11 included in current liabilities as of September 30, 2018. The Company recognized $11 of compensation expense for these options in the nine months ended September 30, 2018.

Commitments And Contingencies

Commitments And Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies [Abstract]
Commitments And Contingencies	7. Commitments and Contingencies Our exploration and development activities are subject to various laws and regulations governing the protection of the environment. These laws and regulations are continually changing and are generally becoming more restrictive. As such, the future expenditures that may be required for compliance with these laws and regulations cannot be predicted. We conduct our operations in an effort to minimize effects on the environment and believe our operations are in compliance with applicable laws and regulations in all material respects. Under our agreement with the Jawoyn Association Aboriginal Corporation (the “JAAC”), we have agreed to offer the JAAC the opportunity to establish a joint venture with Vista holding a 90% participating interest and the JAAC holding a 10% participating interest in Mt Todd. In addition, the JAAC will be entitled to an annual cash payment, or payment in kind, equal to 1% of the value of the annual gold production from the current mining licenses, and a 1% NSR on other metals, subject to a minimum payment of A$50 per year.

Fair Value Accounting

Fair Value Accounting	9 Months Ended
	Sep. 30, 2018
Fair Value [Abstract]
Fair Value Accounting	8. Fair Value Accounting The following table sets forth the Company’s assets measured at fair value by level within the fair value hierarchy. As required by accounting guidance, assets are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Fair value at September 30, 2018 Total Level 1 Level 3 Marketable securities $ 14 $ 14 $ — Other investments (Midas Gold Shares) 5,500 5,500 — Fair value at December 31, 2017 Total Level 1 Level 3 Marketable securities $ 90 $ 90 $ — Other investments (Midas Gold Shares) 3,746 3,746 — Used mill equipment (non-recurring) 6,500 — 6,500 Our marketable securities and investment in Midas Gold Shares are classified as Level 1 of the fair value hierarchy as they are valued at quoted market prices in an active market. Marketable securities are included in other current assets on the Condensed Consolidated Balance Sheets for each period presented. The used mill equipment is classified as Level 3 of the fair value hierarchy as its value at December 31, 2017 was based on an independent third-party valuation. As of September 30, 2018, an independent third-party evaluation was not deemed necessary. The mill equipment is included in plant and equipment on the Condensed Consolidated Balance Sheets for each period presented. There have been no transfers between levels in 2018, nor have there been any changes in valuation techniques.

Geographic And Segment Informat

Geographic And Segment Information	9 Months Ended
	Sep. 30, 2018
Geographic And Segment information [Abstract]
Geographic And Segment Information	9. Geographic and Segment Information The Company has one reportable operating segment. We evaluate, acquire, explore and advance gold exploration and potential development projects, which may lead to gold production or value adding strategic transactions. These activities are currently focused principally in Australia. We reported no revenues during the three and nine months ended September 30, 2018 and 2017. Geographic location of mineral properties and plant and equipment is provided in Notes 4 and 5, respectively.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Event	10. Subsequent Event During October 2018, the Company agreed to extend the due date for the second $1,500 option payment for the Guadalupe de los Reyes project by six months to April 23, 2019. As consideration for the deferral, the Company will receive an additional $150 in cash, $50 of which was paid to the Company on October 24, 2018 and $100 of which Mineral Alamos has agreed to pay by January 23, 2019. In addition, Minera Alamos will pay interest at a rate of 1.5% per month on the unpaid balance of the $1,500 beginning January 24, 2019.

Short-term and Other Investme_2

Short-term and Other Investments (Tables)	9 Months Ended
	Sep. 30, 2018
Short-term and Other Investments [Abstract]
Summary of investment in Midas Gold Shares	September 30, 2018 December 31, 2017 Fair value at beginning of period $ 3,746 $ 4,994 Gain/(loss) during the period 1,754 (1,248) Fair value at end of period $ 5,500 $ 3,746 Midas Gold Shares held at the end of the period 7,802,615 7,802,615

Mineral Properties (Tables)

Mineral Properties (Tables)	9 Months Ended
	Sep. 30, 2018
Mineral Properties [Abstract]
Schedule of Mineral Properties	At September 30, 2018 At December 31, 2017 Mt Todd, Australia $ 2,146 $ 2,146 Guadalupe de los Reyes, Mexico 325 325 $ 2,471 $ 2,471

Plant And Equipment (Tables)

Plant And Equipment (Tables)	9 Months Ended
	Sep. 30, 2018
Plant And Equipment [Abstract]
Schedule Of Plant And Equipment	September 30, 2018 December 31, 2017 Accumulated Accumulated Cost depreciation Net Cost depreciation Net Mt Todd, Australia $ 5,719 $ 4,830 $ 889 $ 5,646 $ 4,591 $ 1,055 Corporate, United States 333 333 — 333 333 — Used mill equipment, Canada 6,500 — 6,500 6,500 — 6,500 $ 12,552 $ 5,163 $ 7,389 $ 12,479 $ 4,924 $ 7,555

Common Shares (Tables)

Common Shares (Tables)	9 Months Ended
	Sep. 30, 2018
Capital Stock [Abstract]
Summary of Warrant Activity	Weighted Weighted average average Warrants exercise price remaining life outstanding per share (yrs.) Intrinsic value As of December 31, 2017 6,514,625 $ 1.92 1.6 $ — As of September 30, 2018 6,514,625 $ 1.92 0.9 $ —
Summary of Stock-based Compensation Expense	Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Stock options $ 107 $ 8 $ 307 $ 32 Restricted stock units 164 245 548 648 $ 271 $ 253 $ 855 $ 680 Phantom units (Discussed below) 11 — 11 —
Summary of Option Activity	Weighted average Weighted average Aggregate Number of exercise price remaining intrinsic options per option contractual term value Outstanding - December 31, 2017 1,144,500 $ 0.42 1.15 $ 346 Granted 1,142,000 0.71 Exercised (40,000) 0.40 Outstanding - September 30, 2018 2,246,500 $ 0.57 2.51 $ 130 Exercisable - September 30, 2018 1,240,581 $ 0.52 1.71 $ 94
Summary of the Status of Unvested Stock Options	Weighted Weighted average average remaining grant-date amortization Number of fair value period options per option (Years) Unvested - December 31, 2017 246,250 $ 0.22 0.99 Granted 1,142,000 0.45 Vested (382,331) 0.45 Unvested - September 30, 2018 1,005,919 $ 0.39 1.24
Summary of Stock Option Assumptions	2018 Expected volatility 76.2 % Risk-free interest rate 2.7 % Expected life (years) 5 Dividend yield — Forfeiture assumption — %
Summary of Restricted Stock Units Activity	Weighted average Number grant-date fair of RSUs value per RSU Unvested - December 31, 2017 1,567,907 $ 0.85 Cancelled/forfeited (246,683) 0.90 Vested, net of shares withheld (637,554) 0.88 Granted 319,000 0.75 Unvested - September 30, 2018 1,002,670 $ 0.78
Summary of Phantom Units	Weighted average Number of remaining phantom units contractual term Unvested - December 31, 2017 — Granted 265,000 Unvested - September 30, 2018 265,000 1.75

Fair Value Accounting (Tables)

Fair Value Accounting (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value [Abstract]
Fair Value Accounting	Fair value at September 30, 2018 Total Level 1 Level 3 Marketable securities $ 14 $ 14 $ — Other investments (Midas Gold Shares) 5,500 5,500 — Fair value at December 31, 2017 Total Level 1 Level 3 Marketable securities $ 90 $ 90 $ — Other investments (Midas Gold Shares) 3,746 3,746 — Used mill equipment (non-recurring) 6,500 — 6,500

Nature of Operations and Basi_2

Nature of Operations and Basis of Presentation (Details) - shares	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Midas Gold Shares [Member]
Property, Plant and Equipment [Line Items]
Shares owned	7,802,615	7,802,615
Mt Todd, Australia [Member]
Property, Plant and Equipment [Line Items]
Percentage of ownership in project	100.00%

Significant Accounting Polici_2

Significant Accounting Policies (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)item	Jan. 01, 2018USD ($)	Dec. 31, 2017USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit	$ (431,903)		$ (426,968)
Revenue recognition
Number of projects currently in production that could provide future variable consideration | item	0
Lease accounting
Liabilities	$ 952		$ 2,058
Accounting Standards Update 2016-02 [Member] | Scenario, Plan [Member] | Minimum [Member]
Lease accounting
Liabilities	125
Accounting Standards Update 2016-02 [Member] | Scenario, Plan [Member] | Maximum [Member]
Lease accounting
Liabilities	225
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit		$ 0
Option Agreement Two [Member] | Guadalupe De Los Reyes, Mexico [Member]
Revenue recognition
Value of carrying value for option payment proceeds to be recognized as contract liability	$ 0

Short-term and Other Investme_3

Short-term and Other Investments, Short-term (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Short-term investments
Short-term investments amortized cost basis	$ 9,029	$ 15,144
Minimum period for maturity dates for short-term investments	90 days

Short-term and Other Investme_4

Short-term and Other Investments, Summary (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Debt and Equity Securities, FV-NI [Line Items]
Fair value at beginning of period			$ 3,746
Gain (loss) during the period	$ (274)	$ (78)	1,754	$ (858)
Fair value at end of period	5,500		5,500		$ 3,746
Midas Gold Shares [Member]
Debt and Equity Securities, FV-NI [Line Items]
Fair value at beginning of period			3,746	$ 4,994	4,994
Gain (loss) during the period			1,754		(1,248)
Fair value at end of period	$ 5,500		$ 5,500		$ 3,746
Midas Gold Shares held at end of the period	7,802,615		7,802,615		7,802,615

Mineral Properties, Properties

Mineral Properties, Properties (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Mineral Properties, Net	$ 2,471	$ 2,471
Mt Todd, Australia [Member]
Property, Plant and Equipment [Line Items]
Mineral Properties, Net	2,146	2,146
Guadalupe De Los Reyes, Mexico [Member]
Property, Plant and Equipment [Line Items]
Mineral Properties, Net	$ 325	$ 325

Mineral Properties, Guadalupe (

Mineral Properties, Guadalupe (Details)	1 Months Ended	9 Months Ended
	Oct. 31, 2017USD ($)item	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Property, Plant and Equipment [Line Items]
Proceeds from option/sales agreements, net			$ 358,000
Guadalupe De Los Reyes, Mexico [Member] | Option Agreement Two [Member]
Property, Plant and Equipment [Line Items]
Interest has right to earn (as a percent)	100.00%
Sale price of gold/silver project	$ 6,000,000
Number of successive payments | item	2
Back in Right (as a percent)	49.00%
Ownership interest if terms of option agreement not fulfilled (as a percent)	0.00%
Ownership to be transferred (as a percent)	100.00%
Proceeds from option/sales agreements, net	$ 1,500,000
Value of carrying value for option payment proceeds to be recognized as contract liability		$ 0
Guadalupe De Los Reyes, Mexico [Member] | Option Agreement Two [Member] | Open Pit Mining [Member]
Property, Plant and Equipment [Line Items]
Aggregate royalty payments to be received	2,000,000
Guadalupe De Los Reyes, Mexico [Member] | Option Agreement Two [Member] | Execution of Option Agreement [Member]
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project	1,500,000
Guadalupe De Los Reyes, Mexico [Member] | Option Agreement Two [Member] | One Year Anniversary [Member]
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project	1,500,000
Guadalupe De Los Reyes, Mexico [Member] | Option Agreement Two [Member] | Two Year Anniversary [Member]
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project	1,500,000
Guadalupe De Los Reyes, Mexico [Member] | Option Agreement Two [Member] | Before Four Year Anniversary [Member]
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project	$ 1,500,000
Guadalupe De Los Reyes, Mexico [Member] | Option Agreement Two [Member] | Minimum [Member] | Open Pit Mining [Member]
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)	1.00%
Gold price (USD per ounce)	$ 1,600
Guadalupe De Los Reyes, Mexico [Member] | Option Agreement Two [Member] | Minimum [Member] | Underground Mining [Member]
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)	1.00%
Gold price (USD per ounce)	$ 1,600
Guadalupe De Los Reyes, Mexico [Member] | Option Agreement Two [Member] | Maximum [Member] | Open Pit Mining [Member]
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)	2.00%
Gold price (USD per ounce)	$ 1,400
Guadalupe De Los Reyes, Mexico [Member] | Option Agreement Two [Member] | Maximum [Member] | Underground Mining [Member]
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)	2.00%
Gold price (USD per ounce)	$ 1,400
Guadalupe De Los Reyes, Mexico [Member] | Minera Gold Stake S A de C V [Member] | Option Agreement Two [Member]
Property, Plant and Equipment [Line Items]
Ownership interest (as a percent)	100.00%

Mineral Properties, Long Valley

Mineral Properties, Long Valley (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Mar. 31, 2017	Sep. 30, 2017
Property, Plant and Equipment [Line Items]
Proceeds from sale		$ 358
Gain on disposal of mineral property		$ 358
Long Valley [Member] | Sold | Mineral Rights
Property, Plant and Equipment [Line Items]
Proceeds from sale	$ 358
Gain on disposal of mineral property	$ 358
Long Valley [Member] | Sold | Mineral Rights | Minimum [Member]
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)	0.50%
Long Valley [Member] | Sold | Mineral Rights | Maximum [Member]
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)	2.00%
Long Valley [Member] | Sold | Mineral Rights | One Month after the Start of Production [Member]
Property, Plant and Equipment [Line Items]
Future payment	$ 500
Long Valley [Member] | Sold | Mineral Rights | On or Prior to the First Anniversary of the Start of Production [Member]
Property, Plant and Equipment [Line Items]
Future payment	$ 500

Plant And Equipment (Details)

Plant And Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Cost	$ 12,552	$ 12,479
Accumulated depreciation	5,163	4,924
Net	7,389	7,555
Mt Todd, Australia [Member]
Property, Plant and Equipment [Line Items]
Cost	5,719	5,646
Accumulated depreciation	4,830	4,591
Net	889	1,055
Corporate, United States [Member]
Property, Plant and Equipment [Line Items]
Cost	333	333
Accumulated depreciation	333	333
Used mill equipment, Canada [Member]
Property, Plant and Equipment [Line Items]
Cost	6,500	6,500
Net	$ 6,500	$ 6,500

Common Shares, Warrants (Detail

Common Shares, Warrants (Details) - Warrants [Member] - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Class of Warrant or Right [Line Items]
Warrants outstanding, beginning of period (in shares)	6,514,625
Warrants outstanding, end of period (in shares)	6,514,625	6,514,625
Weighted average exercise price of warrants outstanding (in dollars per share)	$ 1.92	$ 1.92
Weighted average remaining life, warrants outstanding	10 months 24 days	1 year 7 months 6 days

Common Shares, Stock-Based Comp

Common Shares, Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of issued and outstanding Common Shares			10.00%
Stock-based compensation expense	$ 271	$ 253	$ 855	$ 680
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	107	8	307	32
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	164	$ 245	548	$ 648
Phantom Share Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 11		$ 11

Common Shares, Unrecognized Com

Common Shares, Unrecognized Compensation (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to stock options	$ 223
Weighted average unrecognized compensation recognition period	1 year 2 months 12 days
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to unvested awards	$ 324
Weighted average unrecognized compensation recognition period	10 months 24 days
Phantom Share Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to unvested awards	$ 122
Weighted average unrecognized compensation recognition period	1 year 9 months 18 days

Common Shares, Summary Of Optio

Common Shares, Summary Of Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Capital Stock [Abstract]
Number of options, beginning of period (in shares)	1,144,500
Granted, Number of options (in shares)	1,142,000	0
Number of options, Exercised (in shares)	(40,000)
Number of options, end of period (in shares)	2,246,500		1,144,500
Number of options, Exercisable (in shares)	1,240,581
Weighted average exercise price per option, beginning of period (in dollars per share)	$ 0.42
Weighted average exercise price per option, Granted (in dollars per share)	0.71
Weighted average exercise price per option, Exercised (in dollars per share)	0.40
Weighted average exercise price per option, end of period (in dollars per share)	0.57		$ 0.42
Weighted average exercise price, Exercisable (in dollars per share)	$ 0.52
Weighted average remaining contractual term, Outstanding	2 years 6 months 4 days		1 year 1 month 24 days
Weighted average remaining contractual term, Exercisable	1 year 8 months 16 days
Aggregate intrinsic value, Outstanding, beginning of period (in dollars)	$ 346
Aggregate intrinsic value, Outstanding, end of period (in dollars)	130		$ 346
Aggregate intrinsic value, Options, Exercisable	$ 94

Common Shares, Summary Of The S

Common Shares, Summary Of The Status Of Unvested Stock Options (Details) - $ / shares	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Number of options (in shares)	1,142,000	0
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, Number of options, beginning of period (in shares)	246,250
Granted, Number of options (in shares)	1,142,000
Vested, Number of options (in shares)	(382,331)
Unvested, Number of options, end of period (in shares)	1,005,919		246,250
Unvested, Weighted average grant date fair value, beginning of period (in dollars per share)	$ 0.22
Granted, Weighted average grant-date fair value per option (in dollars per share)	0.45
Vested, Weighted average grant-date fair value per option (in dollars per share)	0.45
Unvested, Weighted average grant date fair value per option, end of period (in dollars per share)	$ 0.39		$ 0.22
Weighted average remaining amortization period	1 year 2 months 27 days		11 months 27 days

Common Shares, Assumptions (Det

Common Shares, Assumptions (Details) - Stock Options [Member]	9 Months Ended
	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility (as a percent)	76.20%
Risk-free interest rate (as a percent)	2.70%
Expected life (years)	5 years

Common Shares, Option Amendment

Common Shares, Option Amendment (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jul. 31, 2018USD ($)item	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Common shares
Current liabilities		$ 952		$ 952		$ 2,058
Stock-based compensation expense		$ 271	$ 253	855	$ 680
Stock Option Agreement 2013 Amendment [Member]
Common shares
Number of executives and directors | item	7
Current liabilities	$ 72
Stock-based compensation expense				$ 0

Common Shares, Summary Of Restr

Common Shares, Summary Of Restricted Stock Units Activity (Details) - Restricted Stock Units (RSUs) [Member]	9 Months Ended
	Sep. 30, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, Number of units, beginning of period (in shares) | shares	1,567,907
Cancelled/forfeited, Number of units (in shares) | shares	(246,683)
Vested, net of shares withheld, Number of units (in shares) | shares	(637,554)
Granted, Number of units (in shares) | shares	319,000
Unvested, Number of units, end of period (in shares) | shares	1,002,670
Unvested, weighted average fair value, beginning of year (in dollars per share) | $ / shares	$ 0.85
Cancelled/forfeited, Weighted average fair value (in dollars per share) | $ / shares	0.90
Vested, Weighted average fair value (in dollars per share) | $ / shares	0.88
Granted, Weighted average fair value (in dollars per share) | $ / shares	0.75
Unvested, weighted average fair value, end of year (in dollars per share) | $ / shares	$ 0.78
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year

Common Shares, Summary Of Phant

Common Shares, Summary Of Phantom Units Activity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Current liabilities	$ 952		$ 952		$ 2,058
Stock-based compensation expense	$ 271	$ 253	$ 855	$ 680
Phantom Share Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Number of units (in shares)			265,000
Unvested, Number of units, end of period (in shares)	265,000		265,000
Weighted average remaining contractual term			1 year 9 months
Current liabilities	$ 11		$ 11
Stock-based compensation expense	$ 11		$ 11

Commitments And Contingencies (

Commitments And Contingencies (Details) - Mt Todd, Australia [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2018AUD ($)
Loss Contingencies [Line Items]
Percentage of ownership in project	100.00%
Scenario, Plan [Member]
Loss Contingencies [Line Items]
Percentage of ownership in project	90.00%
Scenario, Plan [Member] | Jawoyn Association Aboriginal Corporation [Member]
Loss Contingencies [Line Items]
Percentage of ownership in project	10.00%
Percentage of royalty on gold	1.00%
Percentage of royalty on other metals	1.00%
Minimum payment per year	$ 50

Fair Value Accounting (Details)

Fair Value Accounting (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	$ 5,500	$ 3,746
Fair Value Transfers Between Levels	0
Midas Gold Shares [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	5,500	3,746	$ 4,994
Recurring [Member] | Marketable Securities (Other Than Midas Gold Shares) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	14	90
Recurring [Member] | Midas Gold Shares [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	5,500	3,746
Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Marketable Securities (Other Than Midas Gold Shares) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	14	90
Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Midas Gold Shares [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	$ 5,500	3,746
Non-recurring [Member] | Used mill equipment, Canada [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Used mill equipment (non-recurring)		6,500
Non-recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Used mill equipment, Canada [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Used mill equipment (non-recurring)		$ 6,500

Geographic And Segment Inform_2

Geographic And Segment Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)segment	Sep. 30, 2017USD ($)
Geographic And Segment information [Abstract]
Number of reportable segments | segment	1
Revenues | $	$ 0	$ 0

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Oct. 31, 2018	Sep. 30, 2017
Subsequent event
Proceeds from option/sales agreements, net		$ 358
Subsequent Event [Member] | Guadalupe De Los Reyes, Mexico [Member]
Subsequent event
Future payment	$ 1,500
Additional cash consideration	150
Proceeds from option/sales agreements, net	$ 50
Interest rate (as a percent)	1.50%
Subsequent Event [Member] | Guadalupe De Los Reyes, Mexico [Member] | On or Before January 23, 2019 [Member]
Subsequent event
Proceeds from option/sales agreements, net	$ 100
Subsequent Event [Member] | Guadalupe De Los Reyes, Mexico [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-11-01
Subsequent event
Timing of future payment	6 months