Vista Gold (VGZ) 10-K 6 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 13, 2018	Jun. 30, 2017
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	2,017
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Entity Common Stock, Shares Outstanding		99,412,007
Entity Public Float			$ 83,654,000
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 1,431	$ 1,904
Short-term investments (Note 3)	15,144	21,975
Other investments, at fair value (Note 3)	3,746	4,994
Other current assets	794	648
Total current assets	21,115	29,521
Non-current assets:
Mineral properties (Note 4)	2,471	3,874
Plant and equipment, net (Note 5)	7,555	8,213
Total non-current assets	10,026	12,087
Total assets	31,141	41,608
Current liabilities:
Accounts payable	830	252
Accrued liabilities and other	986	481
Provision for environmental liability	242	350
Total current liabilities	2,058	1,083
Total liabilities	2,058	1,083
Commitments and contingencies – (Note 8)
Shareholders' equity:
Common shares, no par value - unlimited shares authorized; shares outstanding: 2017 - 99,412,007 and 2016 - 97,786,608 (Note 6)	456,053	455,443
Accumulated other comprehensive income (loss)	(2)	15
Accumulated deficit	(426,968)	(414,933)
Total shareholders' equity	29,083	40,525
Total liabilities and shareholders' equity	$ 31,141	$ 41,608

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Shareholders' equity:
Common Shares, par value	$ 0	$ 0
Common shares outstanding	99,412,007	97,786,608

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME/(LOSS) AND COMPREHENSIVE INCOME/(LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF INCOME/(LOSS) AND COMPREHENSIVE INCOME/(LOSS) [Abstract]
Revenues	$ 0	$ 0	$ 0
Operating expense:
Exploration, property evaluation and holding costs	(6,931)	(4,303)	(4,265)
Corporate administration	(3,527)	(2,944)	(3,888)
Depreciation and amortization	(655)	(618)	(694)
Gain on disposal of mineral property, net (Note 4)	358	150	1,958
Write-down of value-added tax receivable			(572)
Total operating expense	(10,755)	(7,715)	(7,461)
Non-operating income/(expenses):
Gain on sale of marketable securities			12
Gain/(loss) on other investments (Note 3)	(1,248)	3,196	(1,593)
Research and development grant, net (Note 9)		1,295	10,220
Interest income	111	57	31
Other income/(expense)	(143)	34	(198)
Total non-operating income/(expense)	(1,280)	4,582	8,472
Net income (loss)	(12,035)	(3,133)	1,011
Other comprehensive income (loss):
Unrealized fair value increase/(decrease) on available-for-sale securities	(17)	50	(46)
Comprehensive income (loss)	$ (12,052)	$ (3,083)	$ 965
Basic:
Weighted average number of basic shares outstanding (in shares)	98,627,255	89,064,260	82,571,182
Net income (loss) per share, Basic (in dollars per share)	$ (0.12)	$ (0.04)	$ 0.01
Diluted:
Weighted average number of diluted shares outstanding (in shares)	98,627,255	89,064,260	83,755,080
Net income (loss) per share, Diluted (in dollars per share)	$ (0.12)	$ (0.04)	$ 0.01

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Total
Balances, beginning of period at Dec. 31, 2014	$ 438,083	$ (412,811)	$ 11	$ 25,283
Balances, beginning of period (in shares) at Dec. 31, 2014	82,390,217
Shares issued (RSUs vested/options exercised) (in shares)	493,345
Shares issued (RSUs vested, net of shares withheld) (in shares)				493,345
Stock-based compensation	$ 817			$ 817
Other comprehensive income/(loss)			(46)	(46)
Net loss		1,011		1,011
Balances, end of period at Dec. 31, 2015	$ 438,900	(411,800)	(35)	27,065
Balances, end of period (in shares) at Dec. 31, 2015	82,883,562
Units issued (net of offering costs of $1,425)	$ 15,883			15,883
Units issued (net of offering costs of $1,425) (in shares)	12,362,500
Shares issued (RSUs vested/options exercised)	$ 15			$ 15
Shares issued (RSUs vested/options exercised) (in shares)	2,540,546
Shares issued (RSUs vested, net of shares withheld) (in shares)				2,540,546
Stock-based compensation	$ 645			$ 645
Other comprehensive income/(loss)			50	50
Net loss		(3,133)		(3,133)
Balances, end of period at Dec. 31, 2016	$ 455,443	(414,933)	15	40,525
Balances, end 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			1,625,399
Stock-based compensation	$ 874			$ 874
Other comprehensive income/(loss)			(17)	(17)
Net loss		(12,035)		(12,035)
Balances, end of period at Dec. 31, 2017	$ 456,053	$ (426,968)	$ (2)	$ 29,083
Balances, end of period (in shares) at Dec. 31, 2017	99,412,007

CONSOLIDATED STATEMENTS OF SHA6

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Consolidated Statements Shareholders' Equity [Abstract]
Offering costs	$ 1,425

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income (loss) for the period	$ (12,035)	$ (3,133)	$ 1,011
Adjustments to reconcile net income/(loss) for the period to net cash provided by/(used) in operations:
Depreciation and amortization	655	618	694
Stock-based compensation	874	645	817
Gain on disposal of marketable securities			(12)
Gain on disposal of mineral property	(358)	(150)	(1,958)
Write-down of value-added tax receivable			572
(Gain)/loss on other investments	1,248	(3,196)	1,593
Change in working capital account items:
Other current assets	(160)	(88)	316
Provision for environmental liability	(108)	350
Accounts payable, accrued liabilities and other	1,083	(70)	(24)
Net cash provided by/(used in) operating activities	(8,801)	(5,024)	3,009
Cash flows from investing activities:
Proceeds from sales of marketable securities	6,831		41
Proceeds from sale of other investments, net			2,772
Disposition of short-term investments, net of acquisitions	6,831		41
Disposition of short-term investments, net of acquisitions		(9,985)	(11,990)
Additions to plant and equipment		(37)	(134)
Proceeds from option/sales agreements, net	1,761	150	3,490
Net cash provided by/(used in) investing activities	8,592	(9,872)	(5,821)
Cash flows from financing activities:
Proceeds from equity financings, net		15,883
Payment of taxes from withheld shares	(264)
Proceeds from exercise of stock options		15
Net cash provided by/(used in) financing activities	(264)	15,898
Net increase/(decrease) in cash and cash equivalents	(473)	1,002	(2,812)
Cash and cash equivalents, beginning of period	1,904	902	3,714
Cash and cash equivalents, end of period	$ 1,431	$ 1,904	$ 902

Nature of Operations

Nature of Operations	12 Months Ended
	Dec. 31, 2017
Nature Of Operations [Abstract]
Nature Of Operations	1. Nature of Operations 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. The Company recently received authorization for the last major environmental permit and completed an updated Preliminary Feasibility Study for Mt Todd, which confirms the projects robust economics at today’s gold prices. With these important milestones complete, Vista is in a position to actively pursue strategic alternatives that provide the best opportunity to maximize value for the Company. We also hold 4.2% 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 Indonesia and the United States. All dollar amounts stated herein are in U.S. dollars in thousands, except per share amounts and per warrant amounts unless specified otherwise. References to C$ refer to Canadian currency, AUD or A$ to Australian currency, and USD or $ to United States currency.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Significant Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Accounting Policies Principles of Consolidation The Consolidated Financial Statements include the accounts of Vista Gold Corp. and more-than-50%-owned subsidiaries that it controls and entities over which control is achieved through means other than voting rights. All significant intercompany balances and transactions have been eliminated. The Consolidated Financial Statements have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”). Use of Estimates The preparation of the Company’s Consolidated Financial Statements requires the Company to make estimates and assumptions that affect the reported amounts of assets, liabilities, income and expenses during the reporting period. The more significant areas requiring the use of management estimates and assumptions are: the fair value and accounting treatment of financial instruments ; useful lives of assets for asset depreciation purposes; valuation allowances for deferred tax assets; the fair value and accounting treatment of stock-based compensation; the provision for environmental liabilities; and asset impairments. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances. Accordingly, actual results will likely differ from the amounts estimated in these financial statements. Cash and cash equivalents Cash and cash equivalents include cash on hand and government securities with original maturities of three months or less when purchased. Because of the short maturity of these investments, the carrying amounts approximate their fair value. Foreign Currency Transactions Our functional currency is the U.S. dollar. Foreign currency transactions denominated in currency other than the functional currency are recorded at the approximate rate of exchange at the transaction date and any gains/(losses) resulting therefrom are recorded in other expense. For each of the years ended December 31, 2017, 2016 and 2015, we recorded insignificant net foreign currency gains/(losses). Short-term Investment Short-term investments consist of securities with original maturity dates greater than ninety days and less than one year. These securities are typically United States and Australian government treasury bills and/or notes. Australian dollar denominated treasury bills may result in currency risk associated with fluctuation in exchanges rates. Short-term investments are recorded at amortized cost and are classified as debt securities held-to-maturity as the Company has the intention and ability to hold these instruments until their original maturity date at the time of purchase. Mineral Properties Mineral property acquisition costs, including directly related costs, are capitalized when incurred, and mineral property exploration costs are expensed as incurred. When we determine that a mineral property can be economically developed in accordance with U.S. GAAP and SEC Industry Guide 7 reserves are established, the costs then incurred to develop such property will be capitalized. Capitalized costs will be depleted using the units-of-production method over the estimated life of the proven and probable reserves. If mineral properties are subsequently abandoned or impaired, any undepleted costs will be charged to loss in that period. The recoverability of the carrying values of our mineral properties is dependent upon economic reserves being discovered or developed on the properties, permitting, financing, start-up, and commercial production from, or the sale/lease of, or other strategic transactions related to these properties. Development and/or start-up of any of these projects will depend on, among other things, management’s ability to raise sufficient capital for these purposes. We assess the carrying cost of our mineral properties for impairment whenever information or circumstances indicate the potential for impairment. This would include events and circumstances such as our inability to obtain all the necessary permits, changes in the legal status of our mineral properties, government actions, the results of exploration activities and technical evaluations and changes in economic conditions, including the price of gold and other commodities or input prices. Such evaluations compare estimated future net cash flows with our carrying costs and future obligations on an undiscounted basis. If it is determined that the estimated future undiscounted cash flows are less than the carrying value of the property, a write-down to the estimated fair value will then be reported in our Consolidated Statement of Income/(Loss) and Comprehensive Income/(Loss) for the period. Where estimates of future net cash flows are not determinable and where other conditions indicate the potential for impairment, management uses available market information and/or third-party valuation experts to assess if the carrying value can be recovered and to estimate fair value. Impairment Carrying values of long-lived assets, other than mineral properties, are evaluated for impairment at such time that information becomes available indicating that the carrying value may not be recoverable. If it is determined that the fair value is less than the carrying value an impairment charge equal to the difference between the fair value and the carrying value will be recorded in our Consolidated Statements of Income/(Loss) and Comprehensive Income/(Loss). Stock-Based Compensation Under our stock option and long-term equity incentive plans, stock incentive options and restricted stock units may be granted to executives, employees, consultants and non-employee directors. Compensation expense for such grants is recorded in the Consolidated Statements of Income/(Loss) and Comprehensive Income/(Loss) as a component of Exploration, property evaluation and holding costs and Corporate administration, with a corresponding increase to Common shares in the Consolidated Balance Sheets. The fair values of the options are calculated using the Black-Scholes option pricing model. The fair value of restricted stock units is based on the closing price of our common shares on the grant date. The expense is based on the fair values of the grant on the grant date and is recognized over the vesting period specified for each grant. The fair value and compensation expense related to RSUs and stock options granted to consultants is marked to market at each period until the RSU or stock option vests. Forfeitures for all stock-based compensation are recorded when incurred. Financial Instruments Accounting Standards Codification Topic 820, Fair Value Measurements and Disclosures (“ASC 820”) of the Financial Accounting Standards Board (“FASB”) requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. ASC 820 establishes a fair value hierarchy based on the level of independent, objective evidence surrounding the inputs used to measure fair value. A financial instrument’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. ASC 820 prioritizes the inputs into three levels that may be used to measure fair value: · Level 1 – Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. · Level 2 – Observable inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly, including quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data by correlation or other means. · Level 3 – Prices or valuation techniques requiring inputs that are both significant to the fair value measurement and unobservable. Our financial instruments include cash and cash equivalents, marketable securities, short-term investments, accounts payable and certain other current assets and liabilities. Due to the short-term nature of our cash and cash equivalents, short-term investments, accounts payable and certain other current assets and liabilities, we believe that their carrying amounts approximate fair value. Our marketable securities are classified as available-for-sale. Accordingly, these securities are carried at fair value, which is based upon quoted market prices in an active market and included in Level 1 of the fair value hierarchy. Our other investments, comprised of Midas Gold Shares, are accounted for using the fair value option based on quoted market prices in an active market and is included in Level 1 of the fair value hierarchy. The mill equipment is accounted for using a third-party valuation and is included in Level 3 of the fair value hierarchy. Research and Development (“R&D”) Grants The Company has received Research and Development Tax Incentive payments from the Australian Government. Accounting practice generally refers to International Accounting Standard 20 “Accounting for Government Grants and Disclosure of Government Assistance” (“IAS 20”) to determine the most appropriate accounting for payments of this type. The Company’s activities in Australia do not generate revenue subject to Australian income tax. Consequently, under IAS 20, the R&D Tax Incentive payment is considered a government grant, as opposed to an income tax refund. Grants are recognized when there is reasonable assurance that the grant will be received and that conditions attached to the grant have been met. Recent accounting pronouncements Leases The FASB issued ASU No. 2016-02, Leases. The new standard establishes a right-of-use (“ROU”) model that requires a lessee to record a 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. We are evaluating the impact the adoption of ASU 2016-02 may have. However, based upon our initial reviews, we do not currently anticipate that adoption of this standard will have a significant impact on our financial statements. Revenue Recognition The FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). ASU No. 2014-09, as subsequently amended, supersedes the revenue recognition requirements in Revenue Recognition (Topic 605), and most industry-specific guidance throughout the Industry Topics of the Codification. Additionally, ASU No. 2014-09 supersedes some cost guidance included in Revenue Recognition-Construction-Type and Production-Type Contracts (Subtopic 605-35). 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. Additionally, from time to time, the Company may enter into transactions whereby it sells certain property, plant and equipment. In these instances, certain principles of ASC 606 may apply when recognizing a gain or loss on the transaction even though the transaction is not considered to be in the normal course of business. ASU No. 2014-09 states that entities should apply guidance related to transfer of control and measurement of the transaction price when evaluating the timing and amount of the gain or loss to be recognized. The new guidance is effective for interim and annual periods beginning after December 15, 2017. The Company is evaluating the impact of ASU No. 2014-09 as it relates to the option agreement for Guadalupe de los Reyes, specifically analyzing the impact of any distinct performance obligations, variable consideration and possible constraints. Investments The FASB issued ASU No. 2016-01 was issued related to financial instruments. The new guidance requires entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value and recognize any changes in fair value in net income. This new guidance also updates certain disclosure requirements for these investments. This update is effective in fiscal years, including interim periods, beginning after December 15, 2017, and upon adoption, an entity should apply the amendments with the cumulative effect of initially applying the guidance recognized at January 1, 2018. Early adoption is not permitted. The Company expects the updated guidance to result in a reclassification of unrealized holding gains and losses and deferred income taxes related to investments in marketable equity securities from Accumulated other comprehensive income (loss) to Retained earnings in the Consolidated Balance Sheets upon adoption. Accumulated other comprehensive income (loss) at December 31, 2017 included $17 of unrealized holding gains and losses related to marketable equity securities. Stock-based Compensation The FASB issued ASU 2017-09, Compensation — Stock Compensation — Scope of Modification Accounting (“ASU 2017-09”), which provides guidance about the types of changes to terms or conditions of a share-based payment award that would require an entity to apply modification accounting. The new guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. The amendments in this update should be applied prospectively to an award modified on or after the adoption date Income Taxes On December 22, 2017, Staff Accounting Bulletin No. 118 (“SAB 118”) was issued to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Cuts and Jobs Act. We determine if the assessment of a particular income tax effect is “complete” or “incomplete” as of the due date of the financial statements. Those effects for which the accounting is determined to be complete are reported in the enactment period financial statements. For those effects determined to be incomplete, we determine whether a reasonable estimate of those effects can be made. If a reasonable estimate can be made, the estimate is recognized as a provisional amount. If a reasonable estimate cannot be made, no effects are recognized as provisional amounts until the first reporting period in which a reasonable estimate can be made. Provisional amounts are updated when additional information becomes available and the evaluation of such information is complete. We complete the accounting for all provisional amounts within a measurement period of up to one year from the enactment date.

Other Investments

Other Investments	12 Months Ended
	Dec. 31, 2017
Investments, All Other Investments [Abstract]
Other Investments	3. Other Investments Short-term investments As of December 31, 2017 and 2016, the amortized cost basis of our short-term investments was $15,144 and $21,975, respectively. The amortized cost basis approximates fair value at December 31, 2017 and 2016. Short-term investments at December 31, 2017 are comprised of U.S. government treasury bills and/or notes, while short-term investments at December 31, 2016 were comprised of U.S. government and Australian treasury bills and/or notes, all of which have maturity dates greater than 90 days but less than one year. Other investments - Midas Gold Shares Upon initial recognition of its investment in the Midas Gold Shares, Vista elected to apply the fair value option, and as such, the investment is recorded at fair value in the Consolidated Balance Sheets. Subsequent changes in fair value are recorded in the Consolidated Statements of Income/(Loss) and Comprehensive Income/(Loss) in the period in which they occur. The following table summarizes our investment in Midas Gold Shares as at December 31, 2017 and 2016. December 31, 2017 December 31, 2016 Fair value at beginning of period $ 4,994 $ 1,798 Gain/(loss) during the period (1,248) 3,196 Fair value at end of period $ 3,746 $ 4,994 Midas Gold Shares held at the end of the period 7,802,615 7,802,615

Mineral Properties

Mineral Properties	12 Months Ended
	Dec. 31, 2017
Mineral Properties [Abstract]
Mineral Properties	4. Mineral Properties At December 31, 2017 At December 31, 2016 Mt Todd, Australia $ 2,146 $ 2,146 Guadalupe de los Reyes, Mexico 325 1,728 $ 2,471 $ 3,874 Guadalupe de los Reyes 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 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 royalty 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 royalty 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. Los Cardones In October 2013, we sold our 100% debt and equity participation in the Los Cardones gold project located in Baja California Sur, Mexico (“Los Cardones Sale”) to Invecture and RPG Structrued Finance S.a.R.L. (the “Purchasers”) for a total of $13,000 ($7,000 of which was paid in October 2013 and $6,000 was originally payable January 2014 (the “Subsequent Payment”) subject to the Purchasers’ option to elect to not make the Subsequent Payment). In 2014, the due date for the Subsequent Payment was extended to January 30, 2015 for additional consideration of $500. In October 2014, Invecture announced that the Los Cardones gold project, had been suspended because the conditions for its development were not favorable at that time, which introduced substantial doubt that the Subsequent Payment would be made. After making this announcement, there were no apparent significant favorable changes to incentivize Invecture to lift the suspension. In January 2015, we agreed to amend the payment terms (the “Amendment”) of the Los Cardones Sale. Under the Amendment, t he Company received a payment of $2,994 net of legal costs from the Purchasers as final payment for 100% of the Company’s interest in the project. This resulted in a realized gain of approximately $1,958. Long V alley During 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 net smelter return royalty (“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 sale resulted in a realized gain of $358. Utah Claims During 2016 we sold unpatented mining claims located in Utah for $150 and a 2% net smelter return royalty on any future production from said claims. This resulted in a realized gain of $150.

Plant And Equipment

Plant And Equipment	12 Months Ended
	Dec. 31, 2017
Plant And Equipment [Abstract]
Plant And Equipment	5. Plant and Equipment December 31, 2017 December 31, 2016 Accumulated Accumulated Cost depreciation Net Cost depreciation Net Mt Todd, Australia $ 5,646 $ 4,591 $ 1,055 $ 5,654 $ 3,944 $ 1,710 Guadalupe de los Reyes, Mexico — — — 14 11 3 Corporate, United States 333 333 — 333 333 — Used mill equipment, Canada 6,500 — 6,500 6,500 — 6,500 $ 12,479 $ 4,924 $ 7,555 $ 12,501 $ 4,288 $ 8,213 We continue to actively market the used mill equipment, however, we do not classify it as ‘held for sale’ on our Consolidated Balance Sheets as of December 31, 2017 or 2016 as we do not have reasonable assurance that the mill equipment will sell within 12 months. We are not currently depreciating the used mill equipment as we continue to market it and it is not in use.

Common Shares

Common Shares	12 Months Ended
	Dec. 31, 2017
Capital Stock [Abstract]
Common Shares	6. Common Shares Public Offering, August 2016 During August 2016, we closed a public offering of 12,362,500 units (the “Units”), which included 1,612,500 Units issued pursuant to the full exercise of the underwriters’ over-allotment option, for net proceeds of $15,883 (the “2016 Offering”). Each Unit consisted of one common share in the capital of the Company (“Common Share”) and one-half of one Common Share purchase warrant (each full warrant, a “2016 Warrant”). A total of 6,514,625 2016 Warrants were issued, including 333,375 broker warrants issued to the underwriters. Each 2016 Warrant entitles the holder thereof to purchase one Common Share at a price of $1.92 per Common Share (subject to adjustment in certain circumstances) and is exercisable for a period of 36 months from the closing of the 2016 Offering. The 2016 Warrants, which are classified as equity, had a fair value of $3,320 at the time of the 2016 Offering. The fair value of 2016 Warrants was estimated at the grant date using the Black-Scholes option pricing model using the following assumptions: 1) expected volatility of 89%, 2) risk-free rate of 0.86%, 3) expected life of 3 years, and 4) stock price on the issue date of $1.13 per Common Share. Other Share Issuances During the years ended December 31, 2017, 2016 and 2015, we issued 1,625,399 ; 2,540,546 and 493, 345 common shares, respectively, in connection with the vesting of RSUs and/or stock option exercises. 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, 2014 15,219,802 $ 5.00 0.8 $ — Expired (issued as part of equity financing completed in 2010) (15,219,802) As of December 31, 2015 — — — — Issued 6,514,625 As of December 31, 2016 6,514,625 1.92 2.6 — As of December 31, 2017 6,514,625 $ 1.92 1.6 $ — Stock-Based Compensation Under our Stock Option Plan (the “Plan”) and our Long-Term Equity Incentive Plan (the “LTIP”), we may grant options and/or RSUs or restricted stock awards to our directors, officers, employees and consultants. The combined maximum number of our Common Shares that may be reserved for issuance under the Plan and the LTIP is a variable number equal to 10% of the issued and outstanding Common Shares on a non-diluted basis. Options and RSUs under the Plan and LTIP, respectively, 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 years ended December 31, 2017, 2016 and 2015 is as follows: Year Ended December 31, 2017 2016 2015 Stock options $ 36 $ 23 $ 8 Restricted stock units 838 622 809 $ 874 $ 645 $ 817 As of December 31, 2017, stock options and RSUs had unrecognized compensation expense of $ 10 and $649, respectively, which is expected to be recognized over a weighted average period of 0.99 and 1. 3 years, respectively. Stock Options A summary of option activity under the Plan as of December 31, 2017, 2016 and 2016 and changes during the period then ended 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, 2014 2,257,500 $ 1.60 3.02 $ — Outstanding - December 31, 2015 2,257,500 1.60 2.02 — Granted 50,000 1.11 — Exercised (65,500) 0.39 42 Expired (697,500) 2.91 — Outstanding - December 31, 2016 1,544,500 $ 1.05 1.79 $ 626 Expired (400,000) 2.87 Outstanding - December 31, 2017 1,144,500 $ 0.42 1.15 $ 346 Exercisable - December 31, 2017 898,250 $ 0.43 1.19 $ 262 A summary of our unvested stock options as of December 31, 2017, 2016 and 2015 and changes during the period then ended 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, 2014 246,250 $ 0.22 3.99 Unvested - December 31, 2015 246,250 0.22 3.00 Granted 50,000 0.69 Unvested - December 31, 2016 296,250 $ 0.49 1.23 Vested (50,000) 0.69 Unvested - December 31, 2017 246,250 $ 0.22 0.99 No stock options were granted for the years ended December 31, 2017 and 2015. The fair value of stock options granted during the years ended December 31, 2016 to employees, directors and consultants was estimated at the grant date using the Black-Scholes option pricing model using the following assumptions: 2016 Expected volatility % Risk-free interest rate % Expected life (years) Dividend yield N/A Forfeiture assumption % Option pricing models require the input of highly subjective assumptions, including the expected price volatility. Expected price volatility is based on the historical volatility of our common shares. Changes in the subjective input assumptions can materially affect the fair value estimate. The expected term of the options granted represents the period of time that the options granted are expected to be outstanding. The risk-free rate for the periods within the contractual term of the option is based on the U.S. Treasury yield curve in effect at the date of grant. Restricted Stock Units The following table summarizes the RSU activity under the LTIP as of December 31, 2017, 2016 and 2015 and changes during the years then ended: Weighted average Number grant-date fair of units value per unit Unvested - December 31, 2014 3,692,829 $ 0.74 Cancelled/forfeited (841,038) 0.73 Vested (493,345) 1.62 Granted 1,727,000 0.27 Unvested - December 31, 2015 4,085,446 $ 0.44 Vested (2,475,046) 0.32 Granted 1,057,987 0.84 Unvested - December 31, 2016 2,668,387 $ 0.49 Cancelled/forfeited (441,084) 0.34 Vested, net of shares withheld (1,625,399) 0.38 Granted 966,003 0.82 Unvested - December 31, 2017 1,567,907 $ 0.85 During the year ended December 31, 2017, the Company withheld shares equivalent to the employee withholding tax obligation which resulted from RSUs vesting in the period. Shares withheld are considered cancelled/forfeited. 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 vesting period for all RSUs is at least one year. Weighted Average Common Shares At December 31, 2017 2016 2015 Basic common shares 98,627,255 89,064,260 82,571,182 Effect of dilutive stock-based awards — — 1,183,898 Diluted common shares 98,627,255 89,064,260 83,755,080 Stock options to purchase 1,144,500 common shares, unvested RSUs representing 1,567,907 common shares and 6,514,625 warrants were outstanding at December 31, 2017 but were not included in the computation of diluted weighted average common shares outstanding because their effect would have been anti-dilutive. Stock options to purchase 1,544,500 common shares , unvested RSUs representing 2,668, 387 common shares and 6,514,625 warrants were outstanding at December 31, 2016 but were not included in the computation of diluted weighted average common shares outstanding because their effect would have been anti-dilutive. Stock options to purchase 2,257,500 common shares and unvested RSUs representing 2,901, 548 common shares were outstanding at December 31, 2015 but were not included in the computation of diluted weighted average common shares outstanding because their effect would have been anti-dilutive. During November 2017, the Company entered into an At-the-Market offering agreement (the “ATM Agreement”) with H. C. Wainwright & Co., LLC (“Wainwright”), under which the Company may, but is not obligated to, issue and sell shares of the Company’s common stock through Wainwright as sales manager in an At-the-Market offering under a prospectus supplement for aggregate sales proceeds of up to $10,000 (the “ATM Program”). The ATM Agreement will remain in full force and effect until the earlier of August 31, 2020, or the date that the ATM Agreement is terminated in accordance with the terms therein. Offers or sales of common shares under the ATM Program will be made only in the United States and no offers or sales of common shares under the Agreement will be made in Canada. The common stock will be distributed At-the-Market prices prevailing at the time of sale. As a result, prices of the common stock sold under the ATM Program may vary during the period of distribution. The ATM Agreement provides that Wainwright will be entitled to compensation for its services at a commission rate of 2.0% of the gross sales price per share of common stock sold. The Company reimbursed certain legal expenses of Wainwright totaling $50 and incurred additional accounting, legal, and regulatory costs of approximately $156 in connection with establishing the ATM Program. Such costs have been expensed as incurred during 2017. At December 31, 2017 no offers or sales had been made under the ATM Program.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income/(Loss)	12 Months Ended
	Dec. 31, 2017
Accumulated Other Comprehensive Income [Abstract]
Accumulated Other Comprehensive Income/(Loss)	7. Accumulated Other Comprehensive Income/(Loss) Accumulated Accumulated other comprehensive other comprehensive income/(loss), income/(loss) net of tax As of December 31, 2015 $ (35) $ (29) Other comprehensive loss due to change in fair market value of marketable securities during period before reclassifications 50 43 As of December 31, 2016 $ 15 $ 14 Other comprehensive gain due to change in fair market value of marketable securities during period (17) (14) As of December 31, 2017 $ (2) $ -

Commitments And Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies [Abstract]
Commitments And Contingencies	8. 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 to minimize effects on the environment and believe our operations are in compliance with applicable laws and regulations in all material respects. Under ou r agreement with the Jawoyn Association Aboriginal Corporation (the “JAAC”), we must offer the JAAC the opportunity to establish a joint venture with Vista holding 90% 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 royalty on other metals, subject to a minimum payment of A$50 per year.

Research and Development Grant

Research and Development Grant	12 Months Ended
	Dec. 31, 2017
Research and Development Grant
Research and Development Grant	9. Research and Development Grant The Company received Research & Development (“R&D”) Tax Incentive refunds, net of costs to prepare and file, paid under the Australian Government’s R&D Tax Incentive Program, a program designed to encourage industry to engage in R&D activities that benefit Australia. These refunds are related to costs we incurred during the 2012 through 2015 fiscal years for qualifying R&D programs. The R&D Tax Incentive Program is a self-assessment process, and as such, the Australian Government has the right to audit the qualifying programs and expenditures for a period of four years. As of December 31, 2017, we have not received any notice regarding a formal review from the Australian Government.

Fair Value Accounting

Fair Value Accounting	12 Months Ended
	Dec. 31, 2017
Fair Value [Abstract]
Fair Value Accounting	10. 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 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 Fair value at December 31, 2016 Total Level 1 Level 3 Marketable securities $ 109 $ 109 $ — Other investments (Midas Gold Shares) 4,994 4,994 — 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 Consolidated Balance Sheets for each period presented. The mill equipment is classified as Level 3 of the fair value hierarchy as its value at December 31, 2017 and 2016 was based on an independent third-party valuation. The mill equipment is included in plant and equipment on the Consolidated Balance Sheets for each period presented. There were no transfers between levels nor were there any changes in valuation methods in 2017.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information and Material Non-Cash Transactions	12 Months Ended
	Dec. 31, 2017
Supplemental Cash Flow Information and Material Non Cash Transactions [Abstract]
Supplemental Cash Flow Information and Material NonCash Transactions	11. Supplemental Cash Flow Information and Material Non-Cash Transactions As of December 31, 2017, 2016 and 2015, all of our cash was held in liquid bank deposits and/or government treasury bills/notes in the Unites States and Australia. There were no significant non-cash transactions for the year ended December 31, 2017, 2016 or 2015.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Income Taxes	12. Income Taxes The Company’s U.S. and foreign source income/(loss) is as follows: Years ended December 31, 2017 2016 2015 U.S. $ (2,477) $ 1,219 $ (3,297) Canada (2,119) (1,395) (121) Other Foreign (7,439) (2,957) 4,429 $ (12,035) $ (3,133) $ 1,011 During the years ended December 31, 2017, 2016 and 2015, the Company has recognized ‘nil’ current and deferred income tax expense or benefit in each of the US, Canadian, and other foreign jurisdictions, due to full valuation allowances within each jurisdiction. Rate Reconciliation A reconciliation of the combined income taxes at the statutory rates and the Company’s effective income tax benefit is as follows: Years ended December 31, 2017 2016 2015 Income taxed at statutory rates $ (4,212) $ (1,226) $ 392 Increase (decrease) in taxes from: Stock-based compensation 46 (382) 32 Other adjustments (87) 15 27 Adjustment due to capital transactions (119) R&D grant — 5,936 5,366 Prior year provision to actual adjustments 108 (4,269) (2,894) Change in US tax rate 2,487 Differences in tax rates 563 524 (368) Effect of foreign exchange (99) 379 350 Expiration of NOLs — — 231 Change in valuation allowance 1,194 (977) (3,017) Income tax (benefit)/expense $ — $ — $ — Deferred Taxes Deferred income taxes reflect the net effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The significant components of our deferred tax assets and liabilities as at December 31 are as follows: December 31, 2017 2016 2015 Deferred income tax assets Excess tax basis over book basis of property, plant and equipment $ 7,488 $ 7,773 $ 7,785 Marketable securities 771 713 862 Operating loss carryforwards 28,530 27,943 26,464 Capital loss carryforwards 13,470 13,469 13,463 Other 1,848 1,783 2,725 Total future tax assets 52,107 51,681 51,299 Valuation allowance for future tax assets (51,406) (50,209) (50,816) 701 1,472 483 Deferred income tax liabilities Other investments 701 1,472 483 701 1,472 483 Total Deferred Taxes $ — $ — $ — Valuation Allowance on Canadian and Foreign Tax Assets We establish a valuation allowance against the future income tax assets if, based on available information, it is more likely than not that all of the assets will not be realized. The valuation allowance of $51,406, $50, 209 , and $50,816 at December 31, 2017, 2016 and 2015, respectively, relates mainly to net operating loss carryforwards, in Canada and other foreign tax jurisdictions, where the utilization of such attributes is not more likely than not. The Company continually assesses both positive and negative evidence to determine whether it is more likely than not that deferred tax assets can be realized prior to their expiration. Loss Carryforwards The Company has available income tax losses of $73, 532 , which may be carried forward and applied against future taxable income when earned. The losses expire as follows: Noncapital U.S. Mexico Barbados Total 2017 $ — $ — $ — $ (1) $ (1) 2018 — — — (6) (6) 2019 — — — (20) (20) 2020 — — — (42) (42) 2021 — — — (20) (20) 2022 — — (5,933) (31) (5,964) 2023 — — (325) (22) (347) 2024 — — — (4) (4) 2025 — — (70) (8) (78) 2026 (1,027) — (654) (6) (1,687) 2027 (847) — (205) (6) (1,058) 2028 (5,245) (1,287) — — (6,532) 2029 (4,022) (1,719) — — (5,741) 2030 (5,032) (1,970) — — (7,002) 2031 (3,806) (1,827) — — (5,633) 2032 (6,397) (3,407) — — (9,804) 2033 (6,076) (2,323) — — (8,399) 2034 (4,420) (3,098) — — (7,518) 2035 (3,729) (2) — — (3,731) 2036 (2,799) (2,655) (5,454) 2037 (1,949) (2,542) (4,491) $ (45,349) $ (20,830) $ (7,187) $ (166) $ (73,532) (1) Canadian capital loss carryforwards of $53, 875 and Australian NOLs of $32, 002 , which do not expire and are therefore not included above. During 2016, an income tax benefit and the corresponding valuation allowance of $ 370 related to share-issuance cost was recorded directly to equity. Accounting for uncertainty in taxes Accounting Standards Codification Topic 740 guidance requires that the Company evaluate all income tax positions taken, and recognize a liability for any uncertain tax positions that are not more likely than not to be sustained by the tax authorities. As of December 31, 2017, the Company believes it has no liability for unrecognized tax positions. If the Company were to determine there were any uncertain tax positions, the Company would recognize the liability and related interest and penalties within income tax expense. Tax statute of limitations The Company files income tax returns in Canada, U.S. federal and state jurisdictions and other foreign jurisdictions. There are currently no tax examinations underway for these jurisdictions. Furthermore, the Company is no longer subject to Canadian tax examinations by the Canadian Revenue Authority for years ended on or before December 31, 2014 or U.S. federal income tax examinations by the Internal Revenue Service for years ended on or before December 31, 2014. Some U.S. state and other foreign jurisdictions are still subject for tax examination for years ended on or before December 31, 2013. Although certain tax years are closed under the statute of limitations, tax authorities can still adjust losses being carried forward into open years. Tax reform On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cut and Jobs Act of 2017 (“TCJA”). The passage of this legislation resulted in the change in the U.S. statutory rate from 35% to 21% beginning in January of 2018, the elimination of the corporate alternative minimum tax (“AMT”), the acceleration of depreciation for US tax purposes, limitations on deductibility of interest expense, the elimination of net operating loss carrybacks, and limitations on the use of future losses. In accordance with ASC 740, Income Taxes, the impact of a change in tax law is recorded in the period of enactment. Consequently, the Company has recorded a decrease to its net deferred tax assets of $2,487 with a corresponding net adjustment to the valuation allowance for the year ended December 31, 2017. Based on the Company's current interpretation and subject to the release of the related regulations and any future interpretive guidance, the Company believes the effects of the change in tax law incorporated herein are substantially complete. As a result of other changes introduced by the TCJA, starting with compensation paid in 2018, Section 162(m) will limit us from deducting compensation, including performance-based compensation, in excess of $1,000 paid to anyone who, starting in 2018, serves as the Chief Executive Officer or Chief Financial Officer, or who is among the three most highly compensated executive officers for any fiscal year. The only exception to this rule is for compensation that is paid pursuant to a binding contract in effect on November 2, 2017 that would have otherwise been deductible under the prior Section 162(m) rules. Accordingly, any compensation paid in the future pursuant to new compensation arrangements entered into after November 2, 2017, even if performance-based, will count towards the $1,000 fiscal year deduction limit if paid to a covered executive. Additional information that may affect our income tax accounts and disclosures would include further clarification and guidance on how the Internal Revenue Service will implement tax reform, including guidance with respect to 100% bonus depreciation on self-constructed assets and Section 162(m), further clarification and guidance on how state taxing authorities will implement tax reform and the related effect on our state income tax returns, completion of our 2017 tax return filings, and the potential for additional guidance from the SEC or the FASB related to tax reform .

Geographic And Segment Informat

Geographic And Segment Information	12 Months Ended
	Dec. 31, 2017
Geographic And Segment information [Abstract]
Geographic And Segment Information	13. Geographic and Segment information The Company has one reportable operating segment, consisting of evaluation, acquisition, and exploration activities. 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 years ended December 31, 2017, 2016 and 2015. Geographic location of mineral properties and plant and equipment is provided in Notes 4 and 5, respectively.

Provision for Environmental Lia

Provision for Environmental Liability	12 Months Ended
	Dec. 31, 2017
Environmental Remediation Obligations [Abstract]
Provision for Environmental Liability	14. Provision for Environmental Liability During 2016, the Province of British Columbia Ministry of Energy and Mines (“MEM”) requested that the Company prepare and present to MEM a reclamation plan for closure and abandonment of certain mining claims in British Columbia which the Company had disposed of in 1996. A plan was presented to MEM and we are awaiting a formal response. Assuming no other potentially responsible parties are identified, we have accrued estimated reclamation and other related costs, as of December 31, 2017 and 2016 on an undiscounted basis, which have been included in Exploration, property evaluation and holding costs. It is possible that this estimate may change.

Significant Accounting Polici22

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Significant Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The Consolidated Financial Statements include the accounts of Vista Gold Corp. and more-than-50%-owned subsidiaries that it controls and entities over which control is achieved through means other than voting rights. All significant intercompany balances and transactions have been eliminated. The Consolidated Financial Statements have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”).
Use of Estimates	Use of Estimates The preparation of the Company’s Consolidated Financial Statements requires the Company to make estimates and assumptions that affect the reported amounts of assets, liabilities, income and expenses during the reporting period. The more significant areas requiring the use of management estimates and assumptions are: the fair value and accounting treatment of financial instruments ; useful lives of assets for asset depreciation purposes; valuation allowances for deferred tax assets; the fair value and accounting treatment of stock-based compensation; the provision for environmental liabilities; and asset impairments. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances. Accordingly, actual results will likely differ from the amounts estimated in these financial statements.
Cash and cash equivalents	Cash and cash equivalents Cash and cash equivalents include cash on hand and government securities with original maturities of three months or less when purchased. Because of the short maturity of these investments, the carrying amounts approximate their fair value.
Foreign Currency Translations	Foreign Currency Transactions Our functional currency is the U.S. dollar. Foreign currency transactions denominated in currency other than the functional currency are recorded at the approximate rate of exchange at the transaction date and any gains/(losses) resulting therefrom are recorded in other expense. For each of the years ended December 31, 2017, 2016 and 2015, we recorded insignificant net foreign currency gains/(losses).
Short-term Investment	Short-term Investment Short-term investments consist of securities with original maturity dates greater than ninety days and less than one year. These securities are typically United States and Australian government treasury bills and/or notes. Australian dollar denominated treasury bills may result in currency risk associated with fluctuation in exchanges rates. Short-term investments are recorded at amortized cost and are classified as debt securities held-to-maturity as the Company has the intention and ability to hold these instruments until their original maturity date at the time of purchase.
Mineral Properties	Mineral Properties Mineral property acquisition costs, including directly related costs, are capitalized when incurred, and mineral property exploration costs are expensed as incurred. When we determine that a mineral property can be economically developed in accordance with U.S. GAAP and SEC Industry Guide 7 reserves are established, the costs then incurred to develop such property will be capitalized. Capitalized costs will be depleted using the units-of-production method over the estimated life of the proven and probable reserves. If mineral properties are subsequently abandoned or impaired, any undepleted costs will be charged to loss in that period. The recoverability of the carrying values of our mineral properties is dependent upon economic reserves being discovered or developed on the properties, permitting, financing, start-up, and commercial production from, or the sale/lease of, or other strategic transactions related to these properties. Development and/or start-up of any of these projects will depend on, among other things, management’s ability to raise sufficient capital for these purposes. We assess the carrying cost of our mineral properties for impairment whenever information or circumstances indicate the potential for impairment. This would include events and circumstances such as our inability to obtain all the necessary permits, changes in the legal status of our mineral properties, government actions, the results of exploration activities and technical evaluations and changes in economic conditions, including the price of gold and other commodities or input prices. Such evaluations compare estimated future net cash flows with our carrying costs and future obligations on an undiscounted basis. If it is determined that the estimated future undiscounted cash flows are less than the carrying value of the property, a write-down to the estimated fair value will then be reported in our Consolidated Statement of Income/(Loss) and Comprehensive Income/(Loss) for the period. Where estimates of future net cash flows are not determinable and where other conditions indicate the potential for impairment, management uses available market information and/or third-party valuation experts to assess if the carrying value can be recovered and to estimate fair value.
Impairment	Impairment Carrying values of long-lived assets, other than mineral properties, are evaluated for impairment at such time that information becomes available indicating that the carrying value may not be recoverable. If it is determined that the fair value is less than the carrying value an impairment charge equal to the difference between the fair value and the carrying value will be recorded in our Consolidated Statements of Income/(Loss) and Comprehensive Income/(Loss).
Stock-Based Compensation	Stock-Based Compensation Under our stock option and long-term equity incentive plans, stock incentive options and restricted stock units may be granted to executives, employees, consultants and non-employee directors. Compensation expense for such grants is recorded in the Consolidated Statements of Income/(Loss) and Comprehensive Income/(Loss) as a component of Exploration, property evaluation and holding costs and Corporate administration, with a corresponding increase to Common shares in the Consolidated Balance Sheets. The fair values of the options are calculated using the Black-Scholes option pricing model. The fair value of restricted stock units is based on the closing price of our common shares on the grant date. The expense is based on the fair values of the grant on the grant date and is recognized over the vesting period specified for each grant. The fair value and compensation expense related to RSUs and stock options granted to consultants is marked to market at each period until the RSU or stock option vests. Forfeitures for all stock-based compensation are recorded when incurred.
Financial Instruments	Financial Instruments Accounting Standards Codification Topic 820, Fair Value Measurements and Disclosures (“ASC 820”) of the Financial Accounting Standards Board (“FASB”) requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. ASC 820 establishes a fair value hierarchy based on the level of independent, objective evidence surrounding the inputs used to measure fair value. A financial instrument’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. ASC 820 prioritizes the inputs into three levels that may be used to measure fair value: · Level 1 – Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. · Level 2 – Observable inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly, including quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data by correlation or other means. · Level 3 – Prices or valuation techniques requiring inputs that are both significant to the fair value measurement and unobservable. Our financial instruments include cash and cash equivalents, marketable securities, short-term investments, accounts payable and certain other current assets and liabilities. Due to the short-term nature of our cash and cash equivalents, short-term investments, accounts payable and certain other current assets and liabilities, we believe that their carrying amounts approximate fair value. Our marketable securities are classified as available-for-sale. Accordingly, these securities are carried at fair value, which is based upon quoted market prices in an active market and included in Level 1 of the fair value hierarchy. Our other investments, comprised of Midas Gold Shares, are accounted for using the fair value option based on quoted market prices in an active market and is included in Level 1 of the fair value hierarchy. The mill equipment is accounted for using a third-party valuation and is included in Level 3 of the fair value hierarchy.
Research and Development (“R&D”) Grants	Research and Development (“R&D”) Grants The Company has received Research and Development Tax Incentive payments from the Australian Government. Accounting practice generally refers to International Accounting Standard 20 “Accounting for Government Grants and Disclosure of Government Assistance” (“IAS 20”) to determine the most appropriate accounting for payments of this type. The Company’s activities in Australia do not generate revenue subject to Australian income tax. Consequently, under IAS 20, the R&D Tax Incentive payment is considered a government grant, as opposed to an income tax refund. Grants are recognized when there is reasonable assurance that the grant will be received and that conditions attached to the grant have been met.
Recent accounting pronouncements	Recent accounting pronouncements Leases The FASB issued ASU No. 2016-02, Leases. The new standard establishes a right-of-use (“ROU”) model that requires a lessee to record a 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. We are evaluating the impact the adoption of ASU 2016-02 may have. However, based upon our initial reviews, we do not currently anticipate that adoption of this standard will have a significant impact on our financial statements. Revenue Recognition The FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). ASU No. 2014-09, as subsequently amended, supersedes the revenue recognition requirements in Revenue Recognition (Topic 605), and most industry-specific guidance throughout the Industry Topics of the Codification. Additionally, ASU No. 2014-09 supersedes some cost guidance included in Revenue Recognition-Construction-Type and Production-Type Contracts (Subtopic 605-35). 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. Additionally, from time to time, the Company may enter into transactions whereby it sells certain property, plant and equipment. In these instances, certain principles of ASC 606 may apply when recognizing a gain or loss on the transaction even though the transaction is not considered to be in the normal course of business. ASU No. 2014-09 states that entities should apply guidance related to transfer of control and measurement of the transaction price when evaluating the timing and amount of the gain or loss to be recognized. The new guidance is effective for interim and annual periods beginning after December 15, 2017. The Company is evaluating the impact of ASU No. 2014-09 as it relates to the option agreement for Guadalupe de los Reyes, specifically analyzing the impact of any distinct performance obligations, variable consideration and possible constraints. Investments The FASB issued ASU No. 2016-01 was issued related to financial instruments. The new guidance requires entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value and recognize any changes in fair value in net income. This new guidance also updates certain disclosure requirements for these investments. This update is effective in fiscal years, including interim periods, beginning after December 15, 2017, and upon adoption, an entity should apply the amendments with the cumulative effect of initially applying the guidance recognized at January 1, 2018. Early adoption is not permitted. The Company expects the updated guidance to result in a reclassification of unrealized holding gains and losses and deferred income taxes related to investments in marketable equity securities from Accumulated other comprehensive income (loss) to Retained earnings in the Consolidated Balance Sheets upon adoption. Accumulated other comprehensive income (loss) at December 31, 2017 included $17 of unrealized holding gains and losses related to marketable equity securities. Stock-based Compensation The FASB issued ASU 2017-09, Compensation — Stock Compensation — Scope of Modification Accounting (“ASU 2017-09”), which provides guidance about the types of changes to terms or conditions of a share-based payment award that would require an entity to apply modification accounting. The new guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. The amendments in this update should be applied prospectively to an award modified on or after the adoption date Income Taxes On December 22, 2017, Staff Accounting Bulletin No. 118 (“SAB 118”) was issued to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Cuts and Jobs Act. We determine if the assessment of a particular income tax effect is “complete” or “incomplete” as of the due date of the financial statements. Those effects for which the accounting is determined to be complete are reported in the enactment period financial statements. For those effects determined to be incomplete, we determine whether a reasonable estimate of those effects can be made. If a reasonable estimate can be made, the estimate is recognized as a provisional amount. If a reasonable estimate cannot be made, no effects are recognized as provisional amounts until the first reporting period in which a reasonable estimate can be made. Provisional amounts are updated when additional information becomes available and the evaluation of such information is complete. We complete the accounting for all provisional amounts within a measurement period of up to one year from the enactment date.

Other Investments (Tables)

Other Investments (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, All Other Investments [Abstract]
Summary of investment in Midas Gold Shares	December 31, 2017 December 31, 2016 Fair value at beginning of period $ 4,994 $ 1,798 Gain/(loss) during the period (1,248) 3,196 Fair value at end of period $ 3,746 $ 4,994 Midas Gold Shares held at the end of the period 7,802,615 7,802,615

Mineral Properties (Tables)

Mineral Properties (Tables)	12 Months Ended
	Dec. 31, 2017
Mineral Properties [Abstract]
Schedule of Mineral Properties	At December 31, 2017 At December 31, 2016 Mt Todd, Australia $ 2,146 $ 2,146 Guadalupe de los Reyes, Mexico 325 1,728 $ 2,471 $ 3,874

Plant And Equipment (Tables)

Plant And Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Plant And Equipment [Abstract]
Schedule Of Plant And Equipment	December 31, 2017 December 31, 2016 Accumulated Accumulated Cost depreciation Net Cost depreciation Net Mt Todd, Australia $ 5,646 $ 4,591 $ 1,055 $ 5,654 $ 3,944 $ 1,710 Guadalupe de los Reyes, Mexico — — — 14 11 3 Corporate, United States 333 333 — 333 333 — Used mill equipment, Canada 6,500 — 6,500 6,500 — 6,500 $ 12,479 $ 4,924 $ 7,555 $ 12,501 $ 4,288 $ 8,213 W

Common Shares (Tables)

Common Shares (Tables)	12 Months Ended
	Dec. 31, 2017
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, 2014 15,219,802 $ 5.00 0.8 $ — Expired (issued as part of equity financing completed in 2010) (15,219,802) As of December 31, 2015 — — — — Issued 6,514,625 As of December 31, 2016 6,514,625 1.92 2.6 — As of December 31, 2017 6,514,625 $ 1.92 1.6 $ —
Summary of Stock-based Compensation Expense	Year Ended December 31, 2017 2016 2015 Stock options $ 36 $ 23 $ 8 Restricted stock units 838 622 809 $ 874 $ 645 $ 817
Summary Of Option Activity	Weighted average Weighted average Aggregate Number of exercise price remaining intrinsic options per option contractual term value Outstanding - December 31, 2014 2,257,500 $ 1.60 3.02 $ — Outstanding - December 31, 2015 2,257,500 1.60 2.02 — Granted 50,000 1.11 — Exercised (65,500) 0.39 42 Expired (697,500) 2.91 — Outstanding - December 31, 2016 1,544,500 $ 1.05 1.79 $ 626 Expired (400,000) 2.87 Outstanding - December 31, 2017 1,144,500 $ 0.42 1.15 $ 346 Exercisable - December 31, 2017 898,250 $ 0.43 1.19 $ 262
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, 2014 246,250 $ 0.22 3.99 Unvested - December 31, 2015 246,250 0.22 3.00 Granted 50,000 0.69 Unvested - December 31, 2016 296,250 $ 0.49 1.23 Vested (50,000) 0.69 Unvested - December 31, 2017 246,250 $ 0.22 0.99
Schedule of Share Based Payments Valuation Assumptions	2016 Expected volatility % Risk-free interest rate % Expected life (years) Dividend yield N/A Forfeiture assumption %
Summary Of Restricted Stock Units Activity	Weighted average Number grant-date fair of units value per unit Unvested - December 31, 2014 3,692,829 $ 0.74 Cancelled/forfeited (841,038) 0.73 Vested (493,345) 1.62 Granted 1,727,000 0.27 Unvested - December 31, 2015 4,085,446 $ 0.44 Vested (2,475,046) 0.32 Granted 1,057,987 0.84 Unvested - December 31, 2016 2,668,387 $ 0.49 Cancelled/forfeited (441,084) 0.34 Vested, net of shares withheld (1,625,399) 0.38 Granted 966,003 0.82 Unvested - December 31, 2017 1,567,907 $ 0.85
Weighted Average Common Shares (Table)	At December 31, 2017 2016 2015 Basic common shares 98,627,255 89,064,260 82,571,182 Effect of dilutive stock-based awards — — 1,183,898 Diluted common shares 98,627,255 89,064,260 83,755,080

Accumulated Other Comprehensi27

Accumulated Other Comprehensive Income/(Loss) (Tables)	12 Months Ended
	Dec. 31, 2017
Accumulated Other Comprehensive Income [Abstract]
Reconciliation Of Amounts Contained In Accumulated Other Comprehensive Income	Accumulated Accumulated other comprehensive other comprehensive income/(loss), income/(loss) net of tax As of December 31, 2015 $ (35) $ (29) Other comprehensive loss due to change in fair market value of marketable securities during period before reclassifications 50 43 As of December 31, 2016 $ 15 $ 14 Other comprehensive gain due to change in fair market value of marketable securities during period (17) (14) As of December 31, 2017 $ (2) $ -

Fair Value Accounting (Tables)

Fair Value Accounting (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Accounting [Abstract]
Fair Value Accounting	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 Fair value at December 31, 2016 Total Level 1 Level 3 Marketable securities $ 109 $ 109 $ — Other investments (Midas Gold Shares) 4,994 4,994 — Used mill equipment (non-recurring) 6,500 — 6,500

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Schedule of income/(loss) before income tax, domestic and foreign	Years ended December 31, 2017 2016 2015 U.S. $ (2,477) $ 1,219 $ (3,297) Canada (2,119) (1,395) (121) Other Foreign (7,439) (2,957) 4,429 $ (12,035) $ (3,133) $ 1,011
Schedule of effective income tax rate reconciliation	Years ended December 31, 2017 2016 2015 Income taxed at statutory rates $ (4,212) $ (1,226) $ 392 Increase (decrease) in taxes from: Stock-based compensation 46 (382) 32 Other adjustments (87) 15 27 Adjustment due to capital transactions (119) R&D grant — 5,936 5,366 Prior year provision to actual adjustments 108 (4,269) (2,894) Change in US tax rate 2,487 Differences in tax rates 563 524 (368) Effect of foreign exchange (99) 379 350 Expiration of NOLs — — 231 Change in valuation allowance 1,194 (977) (3,017) Income tax (benefit)/expense $ — $ — $ —
Schedule of deferred tax assets and liabilities	December 31, 2017 2016 2015 Deferred income tax assets Excess tax basis over book basis of property, plant and equipment $ 7,488 $ 7,773 $ 7,785 Marketable securities 771 713 862 Operating loss carryforwards 28,530 27,943 26,464 Capital loss carryforwards 13,470 13,469 13,463 Other 1,848 1,783 2,725 Total future tax assets 52,107 51,681 51,299 Valuation allowance for future tax assets (51,406) (50,209) (50,816) 701 1,472 483 Deferred income tax liabilities Other investments 701 1,472 483 701 1,472 483 Total Deferred Taxes $ — $ — $ —
Summary of expiring loss carryforwards	Noncapital U.S. Mexico Barbados Total 2017 $ — $ — $ — $ (1) $ (1) 2018 — — — (6) (6) 2019 — — — (20) (20) 2020 — — — (42) (42) 2021 — — — (20) (20) 2022 — — (5,933) (31) (5,964) 2023 — — (325) (22) (347) 2024 — — — (4) (4) 2025 — — (70) (8) (78) 2026 (1,027) — (654) (6) (1,687) 2027 (847) — (205) (6) (1,058) 2028 (5,245) (1,287) — — (6,532) 2029 (4,022) (1,719) — — (5,741) 2030 (5,032) (1,970) — — (7,002) 2031 (3,806) (1,827) — — (5,633) 2032 (6,397) (3,407) — — (9,804) 2033 (6,076) (2,323) — — (8,399) 2034 (4,420) (3,098) — — (7,518) 2035 (3,729) (2) — — (3,731) 2036 (2,799) (2,655) (5,454) 2037 (1,949) (2,542) (4,491) $ (45,349) $ (20,830) $ (7,187) $ (166) $ (73,532) (1) Canadian capital loss carryforwards of $53, 875 and Australian NOLs of $32, 002 , which do not expire and are therefore not included above.

Nature of Operations (Details)

Nature of Operations (Details)	12 Months Ended
	Dec. 31, 2017
Midas Gold Shares [Member]
Property, Plant and Equipment [Line Items]
Holding percentage	4.20%
Mt Todd, Australia [Member]
Property, Plant and Equipment [Line Items]
Percentage of ownership in project	100.00%

Significant Accounting Polici31

Significant Accounting Policies (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2017
Significant Accounting Policies [Abstract]
Minimum period for maturity dates for short-term investments		90 days
Unrealized holding gains and losses related to marketable-equity securities		$ 17
Measurement period	1 year

Other Investments, Short-term (

Other Investments, Short-term (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Short-term investments
Short-term investments amortized cost basis	$ 15,144	$ 21,975
Minimum period for maturity dates for short-term investments	90 days

Other Investments, Summary (Det

Other Investments, Summary (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Cost-method Investments [Line Items]
Gain/(loss) during the period	$ (1,248)	$ 3,196	$ (1,593)
Midas Gold Shares [Member]
Schedule of Cost-method Investments [Line Items]
Fair value at beginning of period	4,994	1,798
Gain/(loss) during the period	(1,248)	3,196
Fair value at end of period	$ 3,746	$ 4,994	$ 1,798
Midas Gold Shares held at end of the period	7,802,615	7,802,615

Mineral Properties, Properties

Mineral Properties, Properties (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Mineral Properties, Net	$ 2,471	$ 3,874
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	$ 1,728

Mineral Properties, Guadalupe (

Mineral Properties, Guadalupe (Details) - Guadalupe De Los Reyes, Mexico [Member] - Option Agreement Two [Member] - Minera Alamos, Inc. [Member]	1 Months Ended
	Oct. 31, 2017USD ($)item
Property, Plant and Equipment [Line Items]
Interest has right to earn (as a percent)	100.00%
Sale price of gold/silver project	$ 6,000
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%
Ownership interest (as a percent)	100.00%
Execution of Option Agreement [Member]
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project	$ 1,500,000
One Year Anniversary [Member]
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project	1,500,000
Two Year Anniversary [Member]
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project	1,500,000
Before Four Year Anniversary [Member]
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project	1,500,000
Open Pit Mining [Member]
Property, Plant and Equipment [Line Items]
Aggregate royalty payments to be received	$ 2,000,000
Open Pit Mining [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)	1.00%
Gold price (USD per ounce)	$ 1,600
Open Pit Mining [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)	2.00%
Gold price (USD per ounce)	$ 1,400
Underground Mining [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)	1.00%
Gold price (USD per ounce)	$ 1,600
Underground Mining [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)	2.00%
Gold price (USD per ounce)	$ 1,400

Mineral Properties, Los Cardone

Mineral Properties, Los Cardones (Details) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
	Jan. 31, 2015	Oct. 31, 2013	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Gain on disposal of mineral property, net			$ 358	$ 150	$ 1,958
Los Cardones Sale [Member] | Sold
Property, Plant and Equipment [Line Items]
Percentage of interest sold	100.00%	100.00%
Sale price of gold project		$ 13,000
Proceeds from sale of gold project		7,000
Proceeds from sale of gold project, net of legal costs	$ 2,994
Additional consideration received						$ 500
Future proceeds		$ 6,000
Gain on disposal of mineral property, net	$ 1,958

Mineral Properties, Long Valley

Mineral Properties, Long Valley (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Gain on disposal of mineral property, net	$ 358	$ 150	$ 1,958
Long Valley [Member] | Sold
Property, Plant and Equipment [Line Items]
Proceeds from sale of gold project	358
Gain on disposal of mineral property, net	$ 358
Long Valley [Member] | Sold | Minimum [Member]
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)	0.50%
Long Valley [Member] | Sold | Maximum [Member]
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)	2.00%
Long Valley [Member] | Sold | One Month after the Start of Production [Member]
Property, Plant and Equipment [Line Items]
Future payment to be received	$ 500
Long Valley [Member] | Sold | On or Prior to the First Anniversary of the Start of Production [Member]
Property, Plant and Equipment [Line Items]
Future payment to be received	$ 500

Mineral Properties, Utah (Detai

Mineral Properties, Utah (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Gain on disposal of mineral property, net	$ 358	$ 150	$ 1,958
Utah Sale [Member] | Sold
Property, Plant and Equipment [Line Items]
Proceeds from sale of gold project		$ 150
Net smelter return royalty (as a percent)		2.00%
Gain on disposal of mineral property, net		$ 150

Plant And Equipment (Details)

Plant And Equipment (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)item	Dec. 31, 2016USD ($)
Property, Plant and Equipment [Line Items]
Cost	$ 12,479	$ 12,501
Accumulated depreciation	4,924	4,288
Net	7,555	8,213
Mt Todd, Australia [Member]
Property, Plant and Equipment [Line Items]
Cost	5,646	5,654
Accumulated depreciation	4,591	3,944
Net	1,055	1,710
Guadalupe De Los Reyes, Mexico [Member]
Property, Plant and Equipment [Line Items]
Cost		14
Accumulated depreciation		11
Net		3
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
Number of months to be considered held-for-sale | item	12

Common Shares, Public Offering

Common Shares, Public Offering (Details) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Aug. 31, 2016USD ($)item$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2017$ / shares	Dec. 31, 2014$ / shares
Subsidiary, Sale of Stock [Line Items]
Number of units issued	12,362,500
Proceeds from issuance of common shares | $	$ 15,883	$ 15,883
Number of common shares in each unit | item	1
Number of common shares to purchase each warrant	0.50
Over-Allotment Option
Subsidiary, Sale of Stock [Line Items]
Number of units issued	1,612,500
Warrants [Member]
Subsidiary, Sale of Stock [Line Items]
Issued (in shares)	6,514,625	6,514,625
Number of common shares purchased for each warrant	1
Exercise price (in dollars per share) | $ / shares	$ 1.92	$ 1.92	$ 1.92	$ 5
Period warrants are exercisable	36 months
Fair value of warrants | $	$ 3,320
Expected volatility (as a percent)	89.00%
Risk-free interest rate (as a percent)	0.86%
Expected term (in years)	3 years
Share price (in dollars per share) | $ / shares	$ 1.13
Warrants [Member] | Over-Allotment Option
Subsidiary, Sale of Stock [Line Items]
Issued (in shares)	333,375

Common Shares, Other Share Issu

Common Shares, Other Share Issuances (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Capital Stock [Abstract]
Shares issued (RSUs vested, net of shares withheld) (in shares)	1,625,399	2,540,546	493,345

Common Shares, Warrants (Detail

Common Shares, Warrants (Details) - Warrants [Member] - $ / shares	1 Months Ended	12 Months Ended
	Aug. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Warrants outstanding, beginning of period (in shares)		6,514,625		15,219,802
Warrants expired (in shares)				(15,219,802)
Issued (in shares)	6,514,625		6,514,625
Warrants outstanding, end of period (in shares)		6,514,625	6,514,625		15,219,802
Weighted average exercise price of warrants outstanding (in dollars per share)	$ 1.92	$ 1.92	$ 1.92		$ 5
Weighted average remaining life, warrants outstanding		1 year 7 months 6 days	2 years 7 months 6 days		9 months 18 days

Common Shares, Stock-Based Comp

Common Shares, Stock-Based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Percentage of issued and outstanding Common Shares	10.00%
Stock-based expense	$ 874	$ 645	$ 817
Stock Options [Member]
Stock-based expense	36	23	8
Restricted Stock Units (RSUs) [Member]
Stock-based expense	$ 838	$ 622	$ 809

Common Shares, Unrecognized com

Common Shares, Unrecognized compensation (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to stock options	$ 10
Weighted average compensation recognition period	11 months 27 days
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to unvested awards	$ 649
Weighted average compensation recognition period	1 year 3 months 18 days

Common Shares, Summary Of Optio

Common Shares, Summary Of Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Capital Stock [Abstract]
Number of options, beginning of period (in shares)	1,544,500	2,257,500	2,257,500
Granted, Number of options (in shares)	0	50,000	0
Number of options, Exercised (in shares)		(65,500)
Number of options, Expired (in shares)	(400,000)	(697,500)
Number of options, end of period (in shares)	1,144,500	1,544,500	2,257,500	2,257,500
Number of options, Exercisable (in shares)	898,250
Weighted average exercise price per option, beginning of period (in dollars per share)	$ 1.05	$ 1.60	$ 1.60
Weighted average exercise price per option, Granted (in dollars per share)		1.11
Weighted average exercise price per option, Exercised (in dollars per share)		0.39
Weighted average exercise price per option, Expired (in dollars per share)	2.87	2.91
Weighted average exercise price per option, end of period (in dollars per share)	0.42	$ 1.05	$ 1.60	$ 1.60
Weighted average exercise price, Exercisable (in dollars per share)	$ 0.43
Weighted average remaining contractual term, Outstanding	1 year 1 month 24 days	1 year 9 months 15 days	2 years 7 days	3 years 7 days
Weighted average remaining contractual term, Exercisable	1 year 2 months 9 days
Aggregate intrinsic value, Outstanding, beginning of period (in dollars)	$ 626
Aggregate intrinsic value, Exercised (in dollars)		$ 42
Aggregate intrinsic value, Outstanding, end of period (in dollars)	346	$ 626
Aggregate intrinsic value, Options, Exercisable	$ 262

Common Shares, Summary Of The S

Common Shares, Summary Of The Status Of Unvested Stock Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Capital Stock [Abstract]
Unvested, Number of options, beginning of period (in shares)	296,250	246,250	246,250
Granted, Number of options (in shares)	0	50,000	0
Vested, Number of options (in shares)	(50,000)
Unvested, Number of options, end of period (in shares)	246,250	296,250	246,250	246,250
Unvested, Weighted average grant date fair value, beginning of period (in dollars per share)	$ 0.49	$ 0.22	$ 0.22
Granted, Weighted average grant-date fair value per option (in dollars per share)		0.69
Vested, Weighted average grant-date fair value per option (in dollars per share)	0.69
Unvested, Weighted average grant date fair value per option, end of period (in dollars per share)	$ 0.22	$ 0.49	$ 0.22	$ 0.22
Weighted average remaining amortization period	11 months 27 days	1 year 2 months 23 days	3 years	3 years 11 months 27 days

Common Shares, Assumptions (Det

Common Shares, Assumptions (Details) - Stock Options [Member]	12 Months Ended
	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility (as a percent)	77.68%
Risk-free interest rate (as a percent)	1.12%
Expected life (years)	5 years
Forfeiture assumption (as a percent)	0.00%

Common Shares, Summary Of Restr

Common Shares, Summary Of Restricted Stock Units Activity (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, Number of units, beginning of period (in shares)	2,668,387	4,085,446	3,692,829
Cancelled/forfeited, Number of units (in shares)	(441,084)		(841,038)
Vested, net of shares withheld, Number of units (in shares)	(1,625,399)	(2,475,046)	(493,345)
Granted, Number of units (in shares)	966,003	1,057,987	1,727,000
Unvested, Number of units, end of period (in shares)	1,567,907	2,668,387	4,085,446
Unvested, weighted average fair value, beginning of year (in dollars per share)	$ 0.49	$ 0.44	$ 0.74
Cancelled/forfeited, Weighted average fair value (in dollars per share)	0.34		0.73
Vested, Weighted average fair value (in dollars per share)	0.38	0.32	1.62
Granted, Weighted average fair value (in dollars per share)	0.82	0.84	0.27
Unvested, weighted average fair value, end of year (in dollars per share)	$ 0.85	$ 0.49	$ 0.44
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year

Common Shares, Weighted Average

Common Shares, Weighted Average (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Capital Stock [Abstract]
Basic common shares	98,627,255	89,064,260	82,571,182
Effect of dilutive stock-based awards			1,183,898
Diluted common shares	98,627,255	89,064,260	83,755,080

Common Shares, Anti-dilutive (D

Common Shares, Anti-dilutive (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares outstanding	1,144,500	1,544,500	2,257,500
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares outstanding	1,567,907	2,668,387	2,901,548
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares outstanding	6,514,625	6,514,625

Common Shares, ATM Agreement (D

Common Shares, ATM Agreement (Details) - At-The-Market Offering Agreement [Member] - H. C. Wainwright And Co., LLC [Member] - USD ($) $ in Thousands	1 Months Ended	2 Months Ended
	Nov. 30, 2017	Dec. 31, 2017
Subsidiary, Sale of Stock [Line Items]
Threshold of aggregate sales proceeds	$ 10,000
Offers or sales of common shares under Agreement to be made in Canada	$ 0
Commission rate (as a percent)	2.00%
Reimbursement of certain legal expenses	$ 50
Additional accounting, legal and regulatory costs incurred	$ 156
Offers or sales of common shares		$ 0

Accumulated Other Comprehensi52

Accumulated Other Comprehensive Income/(Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Accumulated other comprehensive income/(loss)
Balances, beginning of period	$ 40,525	$ 27,065
Balances, end of period	29,083	40,525
Accumulated other comprehensive income/(loss) net of tax
Balances, beginning of period	40,525	27,065
Balances, end of period	29,083	40,525
Accumulated Other Comprehensive Income/(Loss) [Member]
Accumulated other comprehensive income/(loss)
Balances, beginning of period	15	(35)
Balances, end of period	(2)	15
Accumulated other comprehensive income/(loss) net of tax
Balances, beginning of period	15	(35)
Balances, end of period	(2)	15
Accumulated due to realization of gain/(loss) on marketable securities [Member]
Accumulated other comprehensive income/(loss)
Other comprehensive (gain) loss loss due to change in fair market value of marketable securities during period before reclassifications	(17)	50
Accumulated other comprehensive income/(loss) net of tax
Other comprehensive loss due to change in fair market value of marketable securities during period before reclassifications	(14)	43
Accumulated other comprehensive income after tax [Member]
Accumulated other comprehensive income/(loss)
Balances, beginning of period	14	(29)
Balances, end of period		14
Accumulated other comprehensive income/(loss) net of tax
Balances, beginning of period	$ 14	(29)
Balances, end of period		$ 14

Commitments And Contingencies (

Commitments And Contingencies (Details) - Mt Todd, Australia [Member] - Jawoyn Association Aboriginal Corporation [Member] AUD in Thousands	12 Months Ended
	Dec. 31, 2017AUD
Loss Contingencies [Line Items]
Percentage of outstanding common shares	90.00%
Percentage of participating interest in gold project by affiliate	10.00%
Percentage of royalty on gold	1.00%
Percentage of royalty on other metals	1.00%
Minimum payment per year	AUD 50

Research and Development Grant

Research and Development Grant (Details)	12 Months Ended
	Dec. 31, 2017
Research and Development Grant
Period for review of program	4 years

Fair Value Accounting (Details)

Fair Value Accounting (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Transfers Between Levels	$ 0
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	90	$ 109
Other investments (Midas Gold Shares)	3,746	4,994
Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	90	109
Other investments (Midas Gold Shares)	3,746	4,994
Non-recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Used mill equipment (non-recurring)	6,500
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]
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

Income Taxes, Source of Income

Income Taxes, Source of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income (loss) before income taxes, total	$ (12,035)	$ (3,133)	$ 1,011
U.S. [Member]
Income (loss) before income taxes, domestic	(2,477)	1,219	(3,297)
Canada [Member]
Income (loss) before income taxes, foreign	(2,119)	(1,395)	(121)
Other Foreign [Member]
Income (loss) before income taxes, foreign	$ (7,439)	$ (2,957)	$ 4,429

Income Taxes, Deferred Tax Expe

Income Taxes, Deferred Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
U.S. [Member]
Current income tax expense (benefit)	$ 0	$ 0	$ 0
Deferred income tax expense (benefit)	0	0	0
Canada [Member]
Current income tax expense (benefit)	0	0	0
Deferred income tax expense (benefit)	0	0	0
Other Foreign [Member]
Current income tax expense (benefit)	0	0	0
Deferred income tax expense (benefit)	$ 0	$ 0	$ 0

Income Taxes, Rate Reconciliati

Income Taxes, Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Income taxed at statutory rates	$ (4,212)	$ (1,226)	$ 392
Stock-based compensation	46	(382)	32
Other adjustments	(87)	15	27
Adjustments due to capital transactions			(119)
R&D grant		5,936	5,366
Prior year provision to actual adjustments	108	(4,269)	(2,894)
Change in US tax rate	2,487
Differences in tax rates	563	524	(368)
Effect of foreign exchange	(99)	379	350
Expiration of NOLs			231
Change in valuation allowance	$ 1,194	$ (977)	$ (3,017)

Income Taxes, Deferred Tax Asse

Income Taxes, Deferred Tax Assets/Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Components of Deferred Tax Assets and Liabilities [Abstract]
Excess tax basis over book basis of property, plant, and equipment	$ 7,488	$ 7,773	$ 7,785
Marketable securities	771	713	862
Operating loss carryforwards	28,530	27,943	26,464
Capital loss carryforwards	13,470	13,469	13,463
Other	1,848	1,783	2,725
Total future tax assets	52,107	51,681	51,299
Valuation allowance for future tax assets	(51,406)	(50,209)	(50,816)
Total income tax assets	701	1,472	483
Other investments	701	1,472	483
Total deferred income tax liabilities	$ 701	$ 1,472	$ 483

Income Taxes, Operating Loss Ca

Income Taxes, Operating Loss Carryforward Expirations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ (73,532)
Total	(73,532)
Income tax benefit and valuation allowance recorded directly to equity		$ 370
Canada [Member]
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(45,349)
Capital loss carryforwards	53,875
U.S. [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(20,830)
Mexico [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(7,187)
Barbados [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(166)
Australia [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	(32,002)
Tax Year 2017 [Member]
Operating Loss Carryforwards [Line Items]
Total	(1)
Tax Year 2017 [Member] | Barbados [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(1)
Tax Year 2018 [Member]
Operating Loss Carryforwards [Line Items]
Total	(6)
Tax Year 2018 [Member] | Barbados [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(6)
Tax Year 2019 [Member]
Operating Loss Carryforwards [Line Items]
Total	(20)
Tax Year 2019 [Member] | Barbados [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(20)
Tax Year 2020[Member]
Operating Loss Carryforwards [Line Items]
Total	(42)
Tax Year 2020[Member] | Barbados [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(42)
Tax Year 2021 [Member]
Operating Loss Carryforwards [Line Items]
Total	(20)
Tax Year 2021 [Member] | Barbados [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(20)
Tax Year 2022 [Member]
Operating Loss Carryforwards [Line Items]
Total	(5,964)
Tax Year 2022 [Member] | Mexico [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(5,933)
Tax Year 2022 [Member] | Barbados [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(31)
Tax Year 2023 [Member]
Operating Loss Carryforwards [Line Items]
Total	(347)
Tax Year 2023 [Member] | Mexico [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(325)
Tax Year 2023 [Member] | Barbados [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(22)
Tax Year 2024 [Member]
Operating Loss Carryforwards [Line Items]
Total	(4)
Tax Year 2024 [Member] | Barbados [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(4)
Tax Year 2025 [Member]
Operating Loss Carryforwards [Line Items]
Total	(78)
Tax Year 2025 [Member] | Mexico [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(70)
Tax Year 2025 [Member] | Barbados [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(8)
Tax Year 2026 [Member]
Operating Loss Carryforwards [Line Items]
Total	(1,687)
Tax Year 2026 [Member] | Canada [Member]
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(1,027)
Tax Year 2026 [Member] | Mexico [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(654)
Tax Year 2026 [Member] | Barbados [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(6)
Tax Year 2027 [Member]
Operating Loss Carryforwards [Line Items]
Total	(1,058)
Tax Year 2027 [Member] | Canada [Member]
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(847)
Tax Year 2027 [Member] | Mexico [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(205)
Tax Year 2027 [Member] | Barbados [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(6)
Tax Year 2028 [Member]
Operating Loss Carryforwards [Line Items]
Total	(6,532)
Tax Year 2028 [Member] | Canada [Member]
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(5,245)
Tax Year 2028 [Member] | U.S. [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(1,287)
Tax Year 2029 [Member]
Operating Loss Carryforwards [Line Items]
Total	(5,741)
Tax Year 2029 [Member] | Canada [Member]
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(4,022)
Tax Year 2029 [Member] | U.S. [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(1,719)
Tax Year 2030 [Member]
Operating Loss Carryforwards [Line Items]
Total	(7,002)
Tax Year 2030 [Member] | Canada [Member]
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(5,032)
Tax Year 2030 [Member] | U.S. [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(1,970)
Tax Year 2031 [Member]
Operating Loss Carryforwards [Line Items]
Total	(5,633)
Tax Year 2031 [Member] | Canada [Member]
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(3,806)
Tax Year 2031 [Member] | U.S. [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(1,827)
Tax Year 2032 [Member]
Operating Loss Carryforwards [Line Items]
Total	(9,804)
Tax Year 2032 [Member] | Canada [Member]
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(6,397)
Tax Year 2032 [Member] | U.S. [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(3,407)
Tax Year 2033 [Member]
Operating Loss Carryforwards [Line Items]
Total	(8,399)
Tax Year 2033 [Member] | Canada [Member]
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(6,076)
Tax Year 2033 [Member] | U.S. [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(2,323)
Tax Year 2034 [Member]
Operating Loss Carryforwards [Line Items]
Total	(7,518)
Tax Year 2034 [Member] | Canada [Member]
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(4,420)
Tax Year 2034 [Member] | U.S. [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(3,098)
Tax year 2035 [Member]
Operating Loss Carryforwards [Line Items]
Total	(3,731)
Tax year 2035 [Member] | Canada [Member]
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(3,729)
Tax year 2035 [Member] | U.S. [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(2)
Tax Year 2036 [Member]
Operating Loss Carryforwards [Line Items]
Total	(5,454)
Tax Year 2036 [Member] | Canada [Member]
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(2,799)
Tax Year 2036 [Member] | U.S. [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(2,655)
Tax Year 2037 [Member]
Operating Loss Carryforwards [Line Items]
Total	(4,491)
Tax Year 2037 [Member] | Canada [Member]
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(1,949)
Tax Year 2037 [Member] | U.S. [Member]
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	$ (2,542)

Income Taxes, Uncertainty (Deta

Income Taxes, Uncertainty (Details) $ in Thousands	Dec. 31, 2017USD ($)
Income Taxes [Abstract]
Unrecognized tax positions	$ 0

Income Taxes, Tax reform (Detai

Income Taxes, Tax reform (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)item	Dec. 31, 2017USD ($)
U.S. statutory rate (as a percent)		35.00%
Decrease in net deferred tax assets		$ 2,487
Scenario, Forecast [Member]
U.S. statutory rate (as a percent)	21.00%
Threshold compensation for deductibility	$ 1,000
Number of most highly compensated executive officers for deductibility of compensation | item	3
Bonus depreciation percentage	100.00%

Geographic And Segment Inform63

Geographic And Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)segment	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Geographic And Segment information [Abstract]
Number of reportable segments | segment	1
Revenues | $	$ 0	$ 0	$ 0

Provision for Environmental L64

Provision for Environmental Liability (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Environmental Remediation Obligations [Abstract]
Provision for environmental liability	$ 242	$ 350