Vista Gold (VGZ) 10-K 25 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Feb. 06, 2019	Jun. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	VISTA GOLD CORP
Entity Central Index Key	783,324
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Entity Common Stock, Shares Outstanding		100,268,161
Entity Public Float			$ 68,703,000
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 1,071	$ 1,431
Short-term investments (Note 3)	6,997	15,144
Other investments, at fair value (Note 3)	5,462	3,746
Other current assets	540	794
Total current assets	14,070	21,115
Non-current assets:
Mineral properties (Note 4)	2,421	2,471
Plant and equipment, net (Note 5)	5,635	7,555
Total non-current assets	8,056	10,026
Total assets	22,126	31,141
Current liabilities:
Accounts payable	195	830
Accrued liabilities and other	435	986
Provision for environmental liability	242	242
Total current liabilities	872	2,058
Total liabilities	872	2,058
Commitments and contingencies – (Note 8)
Shareholders' equity:
Common shares, no par value - unlimited shares authorized; shares outstanding: 2018 - 100,268,161 and 2017 - 99,412,007 (Note 6)	456,938	456,053
Accumulated other comprehensive loss		(2)
Accumulated deficit	(435,684)	(426,968)
Total shareholders' equity	21,254	29,083
Total liabilities and shareholders' equity	$ 22,126	$ 31,141

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Shareholders' equity:
Common Shares, par value	$ 0	$ 0
Common shares outstanding	100,268,161	99,412,007

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME/(LOSS) AND COMPREHENSIVE INCOME/(LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
CONSOLIDATED STATEMENTS OF INCOME/(LOSS) AND COMPREHENSIVE INCOME/(LOSS)
Revenues	$ 0	$ 0
Operating expense:
Exploration, property evaluation and holding costs	$ (4,803)	$ (6,931)
Type of Cost, Good or Service [Extensible List]	us-gaap:MineralExplorationMember	us-gaap:MineralExplorationMember
Corporate administration	$ (4,072)	$ (3,527)
Depreciation and amortization	(983)	(655)
Write-down of plant and equipment (Note 5)	(1,000)
Gain on disposal of mineral properties, net (Note 4)		358
Total operating expense	(10,858)	(10,755)
Non-operating income/(expense):
(Loss)/gain on other investments (Note 3)	1,716	(1,248)
Interest income	368	111
Other income/(expense)	60	(143)
Total non-operating income/(expense)	2,144	(1,280)
Loss before income taxes	(8,714)	(12,035)
Net loss	(8,714)	(12,035)
Other comprehensive loss:
Unrealized fair value increase/ (decrease) on available-for-sale securities		(17)
Comprehensive loss	$ (8,714)	$ (12,052)
Basic:
Weighted average number of shares outstanding (in shares)	99,738,461	98,627,255
Net loss per share, Basic (in dollars per share)	$ (0.09)	$ (0.12)
Diluted:
Weighted average number of shares outstanding (in shares)	99,738,461	98,627,255
Net loss per share, Diluted (in dollars per share)	$ (0.09)	$ (0.12)

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Accumulated Deficit	Accumulated Other Comprehensive Income/(Loss)	Total
Balances, beginning of period at Dec. 31, 2016	$ 455,443	$ (414,933)	$ 15	$ 40,525
Balances, beginning of period (in shares) at Dec. 31, 2016	97,786,608
Shares issued (RSUs vested, net of shares withheld)	$ (264)			(264)
Shares issued (RSUs vested, net of shares withheld) (in shares)	1,625,399
Stock-based compensation	$ 874			874
Other comprehensive loss			(17)	(17)
Net loss		(12,035)		(12,035)
Balances, end of period at Dec. 31, 2017	$ 456,053	(426,968)	(2)	29,083
Balances, end of period (in shares) at Dec. 31, 2017	99,412,007
Cumulative adjustment related to Accounting Standard Update 2016-01 | Accounting Standards Update 2016-01		(2)	$ 2
Cumulative adjustment balance	$ 456,053	(426,970)		29,083
Shares issued (RSUs vested, net of shares withheld)	$ (122)			(122)
Shares issued (RSUs vested, net of shares withheld) (in shares)	637,554
Shares issued (exercise of stock options)	$ 86			$ 86
Shares issued (exercise of stock options) (in shares)	218,600			218,600
Stock-based compensation	$ 982			$ 982
Option amendment (Note 6)	(61)			(61)
Net loss		(8,714)		(8,714)
Balances, end of period at Dec. 31, 2018	$ 456,938	$ (435,684)		$ 21,254
Balances, end of period (in shares) at Dec. 31, 2018	100,268,161

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss for the period	$ (8,714)	$ (12,035)
Adjustments to reconcile net loss for the period to net cash used in operations:
Depreciation and amortization	983	655
Stock-based compensation	982	874
Gain on disposal of mineral property		(358)
Write-down of plant and equipment	1,000
(Gain)/loss on other investments	(1,716)	1,248
Change in working capital account items:
Other current assets	84	(160)
Provision for environmental liability		(108)
Accounts payable, accrued liabilities and other	(1,186)	1,083
Net cash used in operating activities	(8,567)	(8,801)
Cash flows from investing activities:
Proceeds from sales of marketable securities	170
Disposition of short-term investments, net of acquisitions	8,147	6,831
Additions to plant and equipment	(63)
Proceeds from option/sale agreements, net	50	1,761
Net cash provided by investing activities	8,304	8,592
Cash flows from financing activities:
Payment of taxes from withheld shares	(122)	(264)
Option Amendment	(61)
Proceeds from exercise of stock options	86
Net cash used in financing activities	(97)	(264)
Net decrease in cash and cash equivalents	(360)	(473)
Cash and cash equivalents, beginning of period	1,431	1,904
Cash and cash equivalents, end of period	$ 1,071	$ 1,431

Nature of Operations

Nature of Operations	12 Months Ended
	Dec. 31, 2018
Nature of Operations
Nature Of Operations	1. Nature of Operations Vista operates in the gold mining industry. We are focused on the evaluation, acquisition, exploration and advancement of gold exploration, and potential development projects, which may lead to gold production or value adding strategic transactions such as earn-in right agreements, option agreements, leases to third parties, joint venture arrangements with other mining companies, or outright sales of assets for cash and/or other consideration. We look for opportunities to improve the value of our gold projects through exploration drilling and/or technical studies focused on optimizing previous engineering work. The Company’s flagship asset is its 100% owned Mt Todd gold project (“Mt Todd”) in the Northern Territory (“NT”) Australia. Mt Todd is the largest undeveloped gold project in Australia. In January 2018, the Company received authorization for the last major environmental permit and we announced the positive results of an updated preliminary feasibility study (the “PFS”) for Mt Todd. Subsequently, Vista has completed additional metallurgical testing, including ongoing fine grinding evaluations, which demonstrate further improvements in gold recovery. We also hold 7.8 million of the outstanding common shares in the capital of Midas Gold Corp. (“Midas Gold Shares”), a non-core project in Mexico and royalty interests in the United States and Indonesia. 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, 2018
Significant Accounting Policies
Significant Accounting Policies	2. Significant Accounting Policies Principles of Consolidation The Consolidated Financial Statements include the accounts of Vista and more-than-50%-owned subsidiaries that it controls. All significant intercompany balances and transactions have been eliminated. The Consolidated Financial Statements have been prepared in accordance with 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 values. 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, 2018 and 2017, we recorded insignificant net foreign currency gains/(losses). Short-term Investments 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 government treasury bills and/or notes. 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 until April 2018, restricted stock units could 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. 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 are 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. Recent accounting pronouncements Leases In February 2016 the FASB issued ASU No. 2016-02, Leases. The new standard establishes a right-of-use (“ROU”) model that requires a lessee to record an ROU asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. The new standard is effective for interim and annual periods beginning after December 15, 2018. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into, after the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. Based upon our initial review, we expect to recognize additional operating liabilities of approximately $185 on adoption, with corresponding ROU assets of the same amount, based on the present value of the remaining lease payments. Nonemployee Share-Based Payments The FASB issued ASU No. 2018-07, Compensation - Stock Compensation (Topic 718) - Improvements to Nonemployee Share-Based Payment Accounting. ASU No. 2018-07, supersedes the guidance for equity-based payments to nonemployees (Topic ASC 505-50). Under the new standard, an entity should treat equity-based payments to nonemployees the same as stock-based compensation to employees in most cases. The new guidance is effective for interim and annual periods beginning after December 15, 2018, with early adoption permitted. Effective July 1, 2018, the Company adopted the new guidance. The Company performed an assessment of the standard and the impacts on the Company’s Consolidated Financial Statements and disclosures. Based on our analysis, adoption of the standard has not materially changed the Company’s expense recognition and disclosures. Revenue Recognition New FASB guidance issued under ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), as amended, is effective for interim and annual periods beginning after December 15, 2017. Under ASU No. 2014-09, an entity should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU No. 2014-09 also requires additional disclosure about the nature, amount, timing, and uncertainty of revenue and cash flows arising from customer contracts. This includes significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. Effective January 1, 2018, the Company adopted the new guidance modified retrospectively. The Company performed an assessment of the revised guidance and the impacts on the Company’s Consolidated Financial Statements and disclosures. We also evaluated the potential for future variable consideration from option payments, net smelter return royalties (“NSR”), and other production related payments, and determined that there is no impact to the Company’s current accounting. The Company determined that the adoption of this guidance will primarily impact the timing of revenue recognition on certain option agreements based on the Company’s determination of when control is transferred for accounting purposes. Based on the contracts outstanding as of December 31, 2017, there was no cumulative effect adjustment required to be recognized at January 1, 2018. Under the Company’s adoption approach, results for reporting periods beginning after January 1, 2018, will be presented in the Consolidated Financial Statements under the new guidance, while prior period amounts will not be adjusted and continue to be reported under the guidance in effect for those periods. Currently, proceeds received from option agreements are ascribed to recovery of the carrying value of the related project until the carrying value reaches zero. After that, any additional proceeds received will be recognized as a contract liability until control has transferred to the buyer or the related contract has terminated. None of the projects which could provide the Company with future variable consideration are currently in production, and in all cases, we believe there is low probability of future production from these projects. Accordingly, the Company believes its NSRs and other production related payments are fully constrained, and the Company did not record a receivable for them. When it becomes probable that a project which could provide the Company with an NSR or other production related payments could begin production, the Company will evaluate the accounting treatment at that time.

Other Investments

Other Investments	12 Months Ended
	Dec. 31, 2018
Other Investments
Other Investments	3. Other Investments Short-term investments As of December 31, 2018 and 2017, the amortized cost basis of our short-term investments was $6,997 and $15,144, respectively. The amortized cost basis approximates fair value at December 31, 2018 and 2017. Short-term investments at December 31, 2018 and 2017 are comprised of U.S. Government 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, 2018 and 2017. December 31, 2018 December 31, 2017 Fair value at beginning of period $ 3,746 $ 4,994 Gain/(loss) during the period 1,716 (1,248) Fair value at end of period $ 5,462 $ 3,746 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, 2018
Mineral Properties
Mineral Properties	4. Mineral Properties At December 31, 2018 At December 31, 2017 Mt Todd, Australia $ 2,146 $ 2,146 Guadalupe de los Reyes, Mexico 275 325 $ 2,421 $ 2,471 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. In October 2018, the Company agreed to extend the due date for the second $1,500 option payment for the GdlR Project by six months to April 23, 2019. As consideration for the deferral, the Company received an additional $150 in cash, $50 of which was paid to Vista on October 24, 2018 and $100 of which Minera Alamos was paid on January 23, 2019. In addition, Minera Alamos agreed to pay interest at a rate of 1.5% per month on the unpaid balance of the $1,500 payment beginning January 24, 2019. 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 an 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.

Plant And Equipment

Plant And Equipment	12 Months Ended
	Dec. 31, 2018
Plant and Equipment
Plant And Equipment	5. Plant and Equipment December 31, 2018 December 31, 2017 Accumulated Accumulated Cost depreciation Net Cost depreciation Net Mt Todd, Australia $ 5,197 $ 5,062 $ 135 $ 5,646 $ 4,591 $ 1,055 Corporate, United States 333 333 — 333 333 — Used mill equipment, Canada 5,500 — 5,500 6,500 — 6,500 $ 11,030 $ 5,395 $ 5,635 $ 12,479 $ 4,924 $ 7,555 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, 2018 or 2017 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. The Company’s efforts to sell its used mill equipment over the past several years have been unsuccessful. As of December 31, 2018, there are no prospects for an imminent sale of this equipment, and the market conditions conducive to such a sale are not expected to improve in the near future. Based on an independent valuation by a qualified third party, and allowing for selling commissions and costs, the Company has recorded a Level 3 impairment charge of $1,000, which has been included in our Consolidated Statements of Income/(Loss) for the year ended December 31, 2018. December 31, 2018 cost basis and accumulated depreciation totals have been adjusted for fully depreciated assets which are no longer in use and have been removed from service. The Company recorded additional depreciation of $695 in 2018 to adjust the net book value of plant and equipment to account for the cumulative effect of immaterial calculation differences in prior years.

Common Shares

Common Shares	12 Months Ended
	Dec. 31, 2018
Common Shares
Common Shares	6. Common Shares Share Issuances During the years ended December 31, 2018 and 2017 we issued 856,154 and 1,625,399 common shares, respectively, in connection with the vesting of RSUs and/or stock option exercises. Warrants Outstanding warrants are summarized in the following table: Weighted Weighted average average Warrants exercise price remaining life outstanding per share (yrs.) Intrinsic value As of December 31, 2016 6,514,625 $ 1.92 2.6 $ — As of December 31, 2017 6,514,625 $ 1.92 1.6 $ — As of December 31, 2018 6,514,625 $ 1.92 0.6 $ — Stock-Based Compensation Under the Company’s stock option plan (the “Plan”), we may grant options to purchase common shares of the Company (“Common Shares”) to our directors, officers, employees and consultants. The maximum number of our Common Shares that may be reserved for issuance under the Plan, together with RSUs currently outstanding under the Long-Term Incentive Plan (“LTIP”), is a variable number equal to 10% of the issued and outstanding Common Shares on a non-diluted basis at any one time. Options under the Plan are granted from time to time at the discretion of the Board, with vesting periods and other terms as determined by the Board. Stock-based compensation expense for the years ended December 31, 2018 and 2017 is as follows: Year Ended December 31, 2018 2017 Stock options $ 320 $ 36 Restricted stock units 662 838 $ 982 $ 874 Phantom units 23 — As of December 31, 2018, stock options, RSUs, and phantom units had unrecognized compensation expense of $ 159, $210, and $117 respectively, which is expected to be recognized over a weighted average period of 1.1, 0.7 , and 1.5 years, respectively. Stock Options A summary of option activity under the Plan as of December 31, 2018 and 2017 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, 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 Granted 1,142,000 0.71 Exercised (218,600) 0.39 36 Cancelled/Forfeited (748,751) 0.36 Outstanding - December 31, 2018 1,319,149 $ 0.71 3.84 $ 1 Exercisable - December 31, 2018 559,480 $ 0.70 3.23 $ 1 A summary of our unvested stock options as of December 31, 2018 and 2017 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, 2016 296,250 0.49 1.23 Vested (50,000) 0.69 Unvested - December 31, 2017 246,250 $ 0.22 0.99 Granted 1,142,000 0.45 Cancelled/Forfeited (246,250) 0.22 Vested (382,331) 0.45 Unvested - December 31, 2018 759,669 $ 0.45 1.14 No stock options were granted for the year ended December 31, 2017. The fair value of stock options granted during the year ended December 31, 2018 to employees, directors and consultants was estimated at the grant date using the Black-Scholes option pricing model using the following assumptions: 2018 Expected volatility 76.2 % Risk-free interest rate 2.7 % Expected life (years) 5 Dividend yield % Forfeiture assumption — % Option 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. Option Amendment In July 2018, the Company amended certain 2013 stock option agreements, expiring December 30, 2018 subject to the potential for a temporary extension under the terms of the Plan, for seven executives and directors (the “Option Amendment”). The amendment provides each grantee the opportunity to receive a cash buyout of certain vested, unexercised 2013 options in lieu of exercising the option to purchase shares. This cash buyout is based on the intrinsic value of each option at the time of the buyout as determined by the Company’s Compensation Committee prior to the buyout. As a result of this modification, the Company accounted for these options as awards classified as liabilities. The options were previously accounted for as awards classified as equity. The Company recognized no additional compensation expense in the year ended December 31, 2018. In December 2018, all options under the Option Amendment were settled with cash buyouts totaling $61 and the related options were cancelled. Restricted Stock Units The following table summarizes the RSU activity under the LTIP as of December 31, 2018 and 2017 and changes during the years then ended: Weighted average Number grant-date fair of RSUs value per RSU 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 Cancelled/forfeited (246,683) 0.90 Vested, net of shares withheld (637,554) 0.88 Granted 319,000 0.75 Unvested - December 31, 2018 1,002,670 $ 0.78 During the years ended December 31, 2018 and 2017, the Company withheld shares equivalent to the value of employee withholding tax obligations which resulted from RSUs vesting in the period. Shares withheld are considered cancelled/forfeited. Under the LTIP, 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. Of the unvested RSUs, approximately 26% could vest based on a fixed future date, approximately 29% and 45% could vest on performance and market criteria respectively. The vesting period for all RSUs is at least one year. New RSUs will not be granted under the LTIP until the allocation of such awards is duly approved by the shareholders of the Company. Phantom Units Weighted average Number of remaining phantom units contractual term Unvested - December 31, 2017 — Granted 265,000 Unvested - December 31, 2018 265,000 1.50 The Company granted a total of 265,000 phantom units to certain employees during the year ended December 31, 2018. The value of each unit is equal to the Company’s share price on the vesting date and is payable in cash. The phantom units vest on fixed future dates provided the recipient continues to be affiliated with Vista on those dates. Unrecognized compensation expense on these units is based on the Company’s stock price at year end. The Company accounts for these units as awards classified as liabilities with $23 included in current liabilities as of December 31, 2018. The Company recognized $23 of compensation expense for these options in the year ended December 31, 2018. Weighted Average Common Shares At December 31, 2018 2017 Basic common shares 99,738,461 98,627,255 Effect of dilutive stock-based awards — — Diluted common shares 99,738,461 98,627,255 Stock options to purchase 1,319,149 common shares, unvested RSUs representing 1,002,670 common shares, and 6,514,625 warrants to purchase common shares were outstanding at December 31, 2018 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 1,144,500 common shares, unvested RSUs representing 1,567,907 common shares, and 6,514,625 warrants to purchase common shares 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. 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, 2018 and 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, 2018
Accumulated Other Comprehensive Income/(Loss).
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, 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) $ — Cumulative adjustment related to Accounting Standard Update 2016-01 2 As of January 1, 2018 $ — $ — As of December 31, 2018 $ — $ —

Commitments And Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies
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 on other metals, subject to a minimum payment of A$50 per year.

Fair Value Accounting

Fair Value Accounting	12 Months Ended
	Dec. 31, 2018
Fair Value Accounting
Fair Value Accounting	9. 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, 2018 Total Level 1 Level 3 Marketable securities $ — $ — $ — Other investments (Midas Gold Shares) 5,462 5,462 — Used mill equipment (non-recurring) 5,500 — 5,500 Fair value at December 31, 2017 Total Level 1 Level 3 Marketable securities $ 90 $ 90 $ — Other investments (Midas Gold Shares) 3,746 3,746 — Used mill equipment (non-recurring) 6,500 — 6,500 Our marketable securities and investment in Midas Gold Shares are classified as Level 1 of the fair value hierarchy as they are valued at quoted market prices in an active market. Marketable securities are included in other current assets on the 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, 2018 and 2017 was based on an independent third-party valuation. This valuation was based on unobservable inputs obtained by our valuation specialists and reviewed by the Company. 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, 2018
Supplemental Cash Flow Information and Material Non-Cash Transactions
Supplemental Cash Flow Information and Material NonCash Transactions	10. Supplemental Cash Flow Information and Material Non-Cash Transactions As of December 31, 2018 and 2017, all of our cash was held in liquid bank deposits and/or government treasury bills/notes in the Unites States. There were no significant non-cash transactions for the year ended December 31, 2018 or 2017.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Taxes
Income Taxes	11. Income Taxes The Company’s U.S. and foreign source income/(loss) is as follows: Years ended December 31, 2018 2017 U.S. $ (646) $ (2,477) Canada (2,288) (2,119) Other Foreign (5,780) (7,439) $ (8,714) $ (12,035) During the years ended December 31, 2018 and 2017, 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, 2018 2017 Income taxed at statutory rates $ (2,125) $ (4,212) Increase (decrease) in taxes from: Stock-based compensation 79 46 Other adjustments 5 (87) Adjustment due to capital transactions Prior year provision to actual adjustments (2,867) 108 Change in US tax rate — 2,487 Differences in tax rates (339) 563 Effect of foreign exchange (6) (99) Expiration of NOLs — — Change in valuation allowance 5,253 1,194 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, 2018 2017 Deferred income tax assets Excess tax basis over book basis of property, plant and equipment $ 7,488 $ 7,488 Marketable securities 667 771 Operating loss carryforwards 34,052 28,530 Capital loss carryforwards 13,276 13,470 Other 2,031 1,848 Total future tax assets 57,514 52,107 Valuation allowance for future tax assets (56,659) (51,406) 855 701 Deferred income tax liabilities Other investments 855 701 855 701 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 $56,659 and $51,406 at December 31, 2018 and 2017, 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’s tax loss carryforwards expire as follows: Noncapital U.S. Mexico Barbados Total 2018 $ — $ — $ — $ — $ — 2019 — — — — — 2020 — — — — — 2021 — — — (20) (20) 2022 — — (6,184) (31) (6,215) 2023 — — (347) (22) (369) 2024 — — — (4) (4) 2025 — — (74) (6) (80) 2026 (1,027) — (697) (6) (1,730) 2027 (847) — — (6) (853) 2028 (5,245) (1,287) (206) — (6,738) 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 (1,916) (2,482) — — (4,398) 2038 (1,664) — — — (1,664) $ (46,980) $ (20,770) $ (7,508) $ (95) $ (75,353) Note: U.S. loss carryforwards for tax years beginning in 2018 of $2,395, Canadian capital loss carryforwards of $53,883 and Australian NOLs of $46,600, which do not expire, are not included above. 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, 2018, 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, 2015 or U.S. federal income tax examinations by the Internal Revenue Service for years ended on or before December 31, 2015. Some U.S. state and other foreign jurisdictions are still subject to tax examination for years ended on or before December 31, 2014. Although certain tax years are closed under the statute of limitations, tax authorities can still adjust losses being carried forward into open years.

Geographic And Segment Informat

Geographic And Segment Information	12 Months Ended
	Dec. 31, 2018
Geographic and Segment information
Geographic And Segment Information	12. 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, 2018 or 2017. 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, 2018
Provision for Environmental Liability
Provision for Environmental Liability	13. 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, 2018 and 2017 on an undiscounted basis, which have been included in exploration, property evaluation and holding costs.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2018
Subsequent Events
Subsequent Events	14. Subsequent Events There have been no material events subsequent to December 31, 2018.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Significant Accounting Policies
Principles of Consolidation	Principles of Consolidation The Consolidated Financial Statements include the accounts of Vista and more-than-50%-owned subsidiaries that it controls. All significant intercompany balances and transactions have been eliminated. The Consolidated Financial Statements have been prepared in accordance with 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 values.
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, 2018 and 2017, we recorded insignificant net foreign currency gains/(losses).
Short-term Investments	Short-term Investments 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 government treasury bills and/or notes. 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 until April 2018, restricted stock units could 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. 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 are 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.
Recent accounting pronouncements	Recent accounting pronouncements Leases In February 2016 the FASB issued ASU No. 2016-02, Leases. The new standard establishes a right-of-use (“ROU”) model that requires a lessee to record an ROU asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. The new standard is effective for interim and annual periods beginning after December 15, 2018. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into, after the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. Based upon our initial review, we expect to recognize additional operating liabilities of approximately $185 on adoption, with corresponding ROU assets of the same amount, based on the present value of the remaining lease payments. Nonemployee Share-Based Payments The FASB issued ASU No. 2018-07, Compensation - Stock Compensation (Topic 718) - Improvements to Nonemployee Share-Based Payment Accounting. ASU No. 2018-07, supersedes the guidance for equity-based payments to nonemployees (Topic ASC 505-50). Under the new standard, an entity should treat equity-based payments to nonemployees the same as stock-based compensation to employees in most cases. The new guidance is effective for interim and annual periods beginning after December 15, 2018, with early adoption permitted. Effective July 1, 2018, the Company adopted the new guidance. The Company performed an assessment of the standard and the impacts on the Company’s Consolidated Financial Statements and disclosures. Based on our analysis, adoption of the standard has not materially changed the Company’s expense recognition and disclosures. Revenue Recognition New FASB guidance issued under ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), as amended, is effective for interim and annual periods beginning after December 15, 2017. Under ASU No. 2014-09, an entity should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU No. 2014-09 also requires additional disclosure about the nature, amount, timing, and uncertainty of revenue and cash flows arising from customer contracts. This includes significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. Effective January 1, 2018, the Company adopted the new guidance modified retrospectively. The Company performed an assessment of the revised guidance and the impacts on the Company’s Consolidated Financial Statements and disclosures. We also evaluated the potential for future variable consideration from option payments, net smelter return royalties (“NSR”), and other production related payments, and determined that there is no impact to the Company’s current accounting. The Company determined that the adoption of this guidance will primarily impact the timing of revenue recognition on certain option agreements based on the Company’s determination of when control is transferred for accounting purposes. Based on the contracts outstanding as of December 31, 2017, there was no cumulative effect adjustment required to be recognized at January 1, 2018. Under the Company’s adoption approach, results for reporting periods beginning after January 1, 2018, will be presented in the Consolidated Financial Statements under the new guidance, while prior period amounts will not be adjusted and continue to be reported under the guidance in effect for those periods. Currently, proceeds received from option agreements are ascribed to recovery of the carrying value of the related project until the carrying value reaches zero. After that, any additional proceeds received will be recognized as a contract liability until control has transferred to the buyer or the related contract has terminated. None of the projects which could provide the Company with future variable consideration are currently in production, and in all cases, we believe there is low probability of future production from these projects. Accordingly, the Company believes its NSRs and other production related payments are fully constrained, and the Company did not record a receivable for them. When it becomes probable that a project which could provide the Company with an NSR or other production related payments could begin production, the Company will evaluate the accounting treatment at that time.

Other Investments (Tables)

Other Investments (Tables)	12 Months Ended
	Dec. 31, 2018
Other Investments
Summary of investment in Midas Gold Shares	December 31, 2018 December 31, 2017 Fair value at beginning of period $ 3,746 $ 4,994 Gain/(loss) during the period 1,716 (1,248) Fair value at end of period $ 5,462 $ 3,746 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, 2018
Mineral Properties
Schedule of Mineral Properties	At December 31, 2018 At December 31, 2017 Mt Todd, Australia $ 2,146 $ 2,146 Guadalupe de los Reyes, Mexico 275 325 $ 2,421 $ 2,471

Plant And Equipment (Tables)

Plant And Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Plant and Equipment
Schedule Of Plant And Equipment	December 31, 2018 December 31, 2017 Accumulated Accumulated Cost depreciation Net Cost depreciation Net Mt Todd, Australia $ 5,197 $ 5,062 $ 135 $ 5,646 $ 4,591 $ 1,055 Corporate, United States 333 333 — 333 333 — Used mill equipment, Canada 5,500 — 5,500 6,500 — 6,500 $ 11,030 $ 5,395 $ 5,635 $ 12,479 $ 4,924 $ 7,555

Common Shares (Tables)

Common Shares (Tables)	12 Months Ended
	Dec. 31, 2018
Common Shares
Summary of outstanding warrants	Weighted Weighted average average Warrants exercise price remaining life outstanding per share (yrs.) Intrinsic value As of December 31, 2016 6,514,625 $ 1.92 2.6 $ — As of December 31, 2017 6,514,625 $ 1.92 1.6 $ — As of December 31, 2018 6,514,625 $ 1.92 0.6 $ —
Summary of stock-based compensation expense	Year Ended December 31, 2018 2017 Stock options $ 320 $ 36 Restricted stock units 662 838 $ 982 $ 874 Phantom units 23 —
Summary of option activity	Weighted average Weighted average Aggregate Number of exercise price remaining intrinsic options per option contractual term value 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 Granted 1,142,000 0.71 Exercised (218,600) 0.39 36 Cancelled/Forfeited (748,751) 0.36 Outstanding - December 31, 2018 1,319,149 $ 0.71 3.84 $ 1 Exercisable - December 31, 2018 559,480 $ 0.70 3.23 $ 1
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, 2016 296,250 0.49 1.23 Vested (50,000) 0.69 Unvested - December 31, 2017 246,250 $ 0.22 0.99 Granted 1,142,000 0.45 Cancelled/Forfeited (246,250) 0.22 Vested (382,331) 0.45 Unvested - December 31, 2018 759,669 $ 0.45 1.14
Summary of stock option assumptions	2018 Expected volatility 76.2 % Risk-free interest rate 2.7 % Expected life (years) 5 Dividend yield % Forfeiture assumption — %
Summary of restricted stock unit activity	Weighted average Number grant-date fair of RSUs value per RSU 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 Cancelled/forfeited (246,683) 0.90 Vested, net of shares withheld (637,554) 0.88 Granted 319,000 0.75 Unvested - December 31, 2018 1,002,670 $ 0.78
Summary of phantom units	Weighted average Number of remaining phantom units contractual term Unvested - December 31, 2017 — Granted 265,000 Unvested - December 31, 2018 265,000 1.50
Schedule of weighted average common shares	At December 31, 2018 2017 Basic common shares 99,738,461 98,627,255 Effect of dilutive stock-based awards — — Diluted common shares 99,738,461 98,627,255

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income/(Loss) (Tables)	12 Months Ended
	Dec. 31, 2018
Accumulated Other Comprehensive Income/(Loss).
Reconciliation of accumulated other comprehensive income/(loss)	Accumulated Accumulated other comprehensive other comprehensive income/(loss), income/(loss) net of tax 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) $ — Cumulative adjustment related to Accounting Standard Update 2016-01 2 As of January 1, 2018 $ — $ — As of December 31, 2018 $ — $ —

Fair Value Accounting (Tables)

Fair Value Accounting (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Accounting
Schedule of assets measured at fair value	Fair value at December 31, 2018 Total Level 1 Level 3 Marketable securities $ — $ — $ — Other investments (Midas Gold Shares) 5,462 5,462 — Used mill equipment (non-recurring) 5,500 — 5,500 Fair value at December 31, 2017 Total Level 1 Level 3 Marketable securities $ 90 $ 90 $ — Other investments (Midas Gold Shares) 3,746 3,746 — Used mill equipment (non-recurring) 6,500 — 6,500

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Taxes
Schedule of income/(loss) before income tax, domestic and foreign	Years ended December 31, 2018 2017 U.S. $ (646) $ (2,477) Canada (2,288) (2,119) Other Foreign (5,780) (7,439) $ (8,714) $ (12,035)
Schedule of effective income tax rate reconciliation	Years ended December 31, 2018 2017 Income taxed at statutory rates $ (2,125) $ (4,212) Increase (decrease) in taxes from: Stock-based compensation 79 46 Other adjustments 5 (87) Adjustment due to capital transactions Prior year provision to actual adjustments (2,867) 108 Change in US tax rate — 2,487 Differences in tax rates (339) 563 Effect of foreign exchange (6) (99) Expiration of NOLs — — Change in valuation allowance 5,253 1,194 Income tax (benefit)/expense $ — $ —
Schedule of deferred tax assets and liabilities	December 31, 2018 2017 Deferred income tax assets Excess tax basis over book basis of property, plant and equipment $ 7,488 $ 7,488 Marketable securities 667 771 Operating loss carryforwards 34,052 28,530 Capital loss carryforwards 13,276 13,470 Other 2,031 1,848 Total future tax assets 57,514 52,107 Valuation allowance for future tax assets (56,659) (51,406) 855 701 Deferred income tax liabilities Other investments 855 701 855 701 Total Deferred Taxes $ — $ —
Summary of expiring loss carryforwards	Noncapital U.S. Mexico Barbados Total 2018 $ — $ — $ — $ — $ — 2019 — — — — — 2020 — — — — — 2021 — — — (20) (20) 2022 — — (6,184) (31) (6,215) 2023 — — (347) (22) (369) 2024 — — — (4) (4) 2025 — — (74) (6) (80) 2026 (1,027) — (697) (6) (1,730) 2027 (847) — — (6) (853) 2028 (5,245) (1,287) (206) — (6,738) 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 (1,916) (2,482) — — (4,398) 2038 (1,664) — — — (1,664) $ (46,980) $ (20,770) $ (7,508) $ (95) $ (75,353) Note: U.S. loss carryforwards for tax years beginning in 2018 of $2,395, Canadian capital loss carryforwards of $53,883 and Australian NOLs of $46,600, which do not expire, are not included above.

Nature of Operations (Details)

Nature of Operations (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Midas Gold Shares
Property, Plant and Equipment [Line Items]
Shares owned	7,802,615	7,802,615
Mt Todd, Australia
Property, Plant and Equipment [Line Items]
Percentage of ownership in project	100.00%

Significant Accounting Polici_3

Significant Accounting Policies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)item	Jan. 01, 2019USD ($)	Jan. 01, 2018USD ($)	Dec. 31, 2017USD ($)
Significant Accounting Policies
Minimum period for maturity dates for short-term investments	90 days
Accumulated deficit	$ (435,684)			$ (426,968)
Revenue recognition
Number of projects currently in production that could provide future variable consideration | item	0
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Significant Accounting Policies
Accumulated deficit			$ 0
Restatement adjustment | Accounting Standards Update 2016-02
Lease accounting
Operating lease liabilities		$ 185
Right of use operating assets		$ 185
Option Agreement Two | Guadalupe De Los Reyes, Mexico
Revenue recognition
Value of carrying value for option payment proceeds to be recognized as contract liability	$ 0

Other Investments, Short-term (

Other Investments, Short-term (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Short-term investments
Short-term investments amortized cost basis	$ 6,997	$ 15,144
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, 2018	Dec. 31, 2017
Other Investments
Fair value at beginning of period	$ 3,746
Gain (loss) during the period	1,716	$ (1,248)
Fair value at end of period	5,462	3,746
Midas Gold Shares
Other Investments
Fair value at beginning of period	3,746	4,994
Gain (loss) during the period	1,716	(1,248)
Fair value at end of period	$ 5,462	$ 3,746
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, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Mineral Properties, Net	$ 2,421	$ 2,471
Mt Todd, Australia
Property, Plant and Equipment [Line Items]
Mineral Properties, Net	2,146	2,146
Guadalupe De Los Reyes, Mexico
Property, Plant and Equipment [Line Items]
Mineral Properties, Net	$ 275	$ 325

Mineral Properties, Guadalupe (

Mineral Properties, Guadalupe (Details)	Jan. 23, 2019USD ($)	Oct. 24, 2018USD ($)	Oct. 31, 2018USD ($)	Oct. 31, 2017USD ($)item	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Property, Plant and Equipment [Line Items]
Proceeds from option/sale agreements, net					$ 50,000	$ 1,761,000
Guadalupe De Los Reyes, Mexico
Property, Plant and Equipment [Line Items]
Proceeds from option/sale agreements, net	$ 100,000	$ 50,000
Interest rate (as a percent)			1.50%
Guadalupe De Los Reyes, Mexico | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-10-01
Property, Plant and Equipment [Line Items]
Future payment			$ 1,500,000
Timing of future payment			6 months
Guadalupe De Los Reyes, Mexico | On or Before January 23, 2019
Property, Plant and Equipment [Line Items]
Proceeds from option/sale agreements, net			$ 150,000
Guadalupe De Los Reyes, Mexico | Option Agreement Two
Property, Plant and Equipment [Line Items]
Interest has right to earn (as a percent)				100.00%
Sale price of gold/silver project				$ 6,000,000
Number of successive payments | item				2
Back in Right (as a percent)				49.00%
Ownership interest if terms of option agreement not fulfilled (as a percent)				0.00%
Ownership to be transferred (as a percent)				100.00%
Value of carrying value for option payment proceeds to be recognized as contract liability					$ 0
Guadalupe De Los Reyes, Mexico | Option Agreement Two | Open Pit Mining
Property, Plant and Equipment [Line Items]
Aggregate royalty payments to be received				$ 2,000,000
Guadalupe De Los Reyes, Mexico | Option Agreement Two | Execution of Option Agreement
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project				1,500,000
Guadalupe De Los Reyes, Mexico | Option Agreement Two | One Year Anniversary
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project				1,500,000
Guadalupe De Los Reyes, Mexico | Option Agreement Two | Two Year Anniversary
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project				1,500,000
Guadalupe De Los Reyes, Mexico | Option Agreement Two | Before Four Year Anniversary
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project				$ 1,500,000
Guadalupe De Los Reyes, Mexico | Option Agreement Two | Minimum | Open Pit Mining
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)				1.00%
Gold price (USD per ounce)				$ 1,600
Guadalupe De Los Reyes, Mexico | Option Agreement Two | Minimum | Underground Mining
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)				1.00%
Gold price (USD per ounce)				$ 1,600
Guadalupe De Los Reyes, Mexico | Option Agreement Two | Maximum | Open Pit Mining
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)				2.00%
Gold price (USD per ounce)				$ 1,400
Guadalupe De Los Reyes, Mexico | Option Agreement Two | Maximum | Underground Mining
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)				2.00%
Gold price (USD per ounce)				$ 1,400
Guadalupe De Los Reyes, Mexico | Minera Gold Stake S A de C V | Option Agreement Two
Property, Plant and Equipment [Line Items]
Ownership interest (as a percent)				100.00%

Mineral Properties, Long Valley

Mineral Properties, Long Valley (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Proceeds from sale	$ 50	$ 1,761
Gain on disposal of mineral property		358
Long Valley [Member] | Sold | Mineral Rights
Property, Plant and Equipment [Line Items]
Proceeds from sale		358
Gain on disposal of mineral property		$ 358
Long Valley [Member] | Sold | Mineral Rights | Minimum
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)		0.50%
Long Valley [Member] | Sold | Mineral Rights | Maximum
Property, Plant and Equipment [Line Items]
Net smelter return royalty (as a percent)		2.00%
Long Valley [Member] | Sold | Mineral Rights | One Month after the Start of Production [Member]
Property, Plant and Equipment [Line Items]
Future payment		$ 500
Long Valley [Member] | Sold | Mineral Rights | On or Prior to the First Anniversary of the Start of Production [Member]
Property, Plant and Equipment [Line Items]
Future payment		$ 500

Plant And Equipment (Details)

Plant And Equipment (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)item	Dec. 31, 2017USD ($)
Property, Plant and Equipment [Line Items]
Cost	$ 11,030	$ 12,479
Accumulated depreciation	5,395	4,924
Net	5,635	7,555
Impairment charge	1,000
Immaterial calculation differences
Property, Plant and Equipment [Line Items]
Depreciation	695
Mt Todd, Australia
Property, Plant and Equipment [Line Items]
Cost	5,197	5,646
Accumulated depreciation	5,062	4,591
Net	135	1,055
Corporate, United States
Property, Plant and Equipment [Line Items]
Cost	333	333
Accumulated depreciation	333	333
Used mill equipment, Canada
Property, Plant and Equipment [Line Items]
Cost	5,500	6,500
Net	$ 5,500	$ 6,500
Number of months to be considered held-for-sale | item	12
Impairment charge	$ 1,000

Common Shares - Share Issuances

Common Shares - Share Issuances (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Common Shares
Shares issued (RSUs vested and options (in shares)	856,154	1,625,399

Common Shares - Warrants (Detai

Common Shares - Warrants (Details) - Warrants - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares)	6,514,625	6,514,625	6,514,625
Weighted average exercise price of warrants outstanding (in dollars per share)	$ 1.92	$ 1.92	$ 1.92
Weighted average remaining life, warrants outstanding	7 months 6 days	1 year 7 months 6 days	2 years 7 months 6 days

Common Shares - Stock-Based Com

Common Shares - Stock-Based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of issued and outstanding Common Shares	10.00%
Stock-based compensation expense	$ 982	$ 874
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	320	36
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	662	$ 838
Phantom Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 23

Common Shares - Unrecognized Co

Common Shares - Unrecognized Compensation (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to stock options	$ 159
Weighted average unrecognized compensation recognition period	1 year 1 month 6 days
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to unvested awards	$ 210
Weighted average unrecognized compensation recognition period	8 months 12 days
Phantom Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to unvested awards	$ 117
Weighted average unrecognized compensation recognition period	1 year 6 months

Common Shares - Summary Of Opti

Common Shares - Summary Of Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Common Shares
Number of options, beginning of period (in shares)	1,144,500	1,544,500
Number of options, Expired (in shares)		(400,000)
Granted, Number of options (in shares)	1,142,000	0
Number of options, Exercised (in shares)	(218,600)
Number of options, Cancelled/Forfeited (in shares)	(748,751)
Number of options, end of period (in shares)	1,319,149	1,144,500	1,544,500
Number of options, Exercisable (in shares)	559,480
Weighted average exercise price per option, beginning of period (in dollars per share)	$ 0.42	$ 1.05
Weighted average exercise price per option, Expired (in dollars per share)		2.87
Weighted average exercise price per option, Granted (in dollars per share)	0.71
Weighted average exercise price per option, Exercised (in dollars per share)	0.39
Weighted average exercise price per option, Cancelled/Forfeited (in dollars per share)	0.36
Weighted average exercise price per option, end of period (in dollars per share)	0.71	$ 0.42	$ 1.05
Weighted average exercise price, Exercisable (in dollars per share)	$ 0.70
Weighted average remaining contractual term, Outstanding	3 years 10 months 2 days	1 year 1 month 24 days	1 year 9 months 15 days
Weighted average remaining contractual term, Exercisable	3 years 2 months 23 days
Aggregate intrinsic value, Outstanding, beginning of period (in dollars)	$ 346	$ 626
Aggregate intrinsic value, Exercised (in dollars)	36
Aggregate intrinsic value, Outstanding, end of period (in dollars)	1	$ 346	$ 626
Aggregate intrinsic value, Options, Exercisable	$ 1

Common Shares - Summary Of The

Common Shares - Summary Of The Status Of Unvested Stock Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Number of options (in shares)	1,142,000	0
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, Number of options, beginning of period (in shares)	246,250	296,250
Granted, Number of options (in shares)	1,142,000
Cancelled/Forfeited, Number of options (in shares)	(246,250)
Vested, Number of options (in shares)	(382,331)	(50,000)
Unvested, Number of options, end of period (in shares)	759,669	246,250	296,250
Unvested, Weighted average grant date fair value, beginning of period (in dollars per share)	$ 0.22	$ 0.49
Granted, Weighted average grant-date fair value per option (in dollars per share)	0.45
Cancelled/Forfeited, Weighted average grant-date fair value per option (in dollars per share)	0.22
Vested, Weighted average grant-date fair value per option (in dollars per share)	0.45	0.69
Unvested, Weighted average grant date fair value per option, end of period (in dollars per share)	$ 0.45	$ 0.22	$ 0.49
Weighted average remaining amortization period	1 year 1 month 21 days	11 months 27 days	1 year 2 months 23 days

Common Shares - Assumptions (De

Common Shares - Assumptions (Details) - Stock Options	12 Months Ended
	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility (as a percent)	76.20%
Risk-free interest rate (as a percent)	2.70%
Expected life (years)	5 years
Dividend yield	0.00%

Common Shares - Option Amendmen

Common Shares - Option Amendment (Details) $ in Thousands	1 Months Ended		12 Months Ended
	Dec. 31, 2018USD ($)	Jul. 31, 2018item	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Common shares
Stock-based compensation expense			$ 982	$ 874
Stock Option Agreement 2013 Amendment
Common shares
Number of executives and directors | item		7
Stock-based compensation expense			$ 0
Cash buyouts of unexercised stock options	$ 61

Common Shares - Summary Of Rest

Common Shares - Summary Of Restricted Stock Units Activity (Details) - Restricted Stock Units (RSUs) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, Number of units, beginning of period (in shares)	1,567,907	2,668,387
Cancelled/forfeited, Number of units (in shares)	(246,683)	(441,084)
Vested, net of shares withheld, Number of units (in shares)	(637,554)	(1,625,399)
Granted, Number of units (in shares)	319,000	966,003
Unvested, Number of units, end of period (in shares)	1,002,670	1,567,907
Unvested, weighted average fair value, beginning of year (in dollars per share)	$ 0.85	$ 0.49
Cancelled/forfeited, Weighted average fair value (in dollars per share)	0.90	0.34
Vested, Weighted average fair value (in dollars per share)	0.88	0.38
Granted, Weighted average fair value (in dollars per share)	0.75	0.82
Unvested, weighted average fair value, end of year (in dollars per share)	$ 0.78	$ 0.85
Fixed future date
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting (as a percent)	26.00%
Performance criteria
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting (as a percent)	29.00%
Market criteria
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting (as a percent)	45.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year

Common Shares - Summary Of Phan

Common Shares - Summary Of Phantom Units Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Current liabilities	$ 872	$ 2,058
Stock-based compensation expense	$ 982	$ 874
Phantom Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Number of units (in shares)	265,000
Unvested, Number of units, end of period (in shares)	265,000
Weighted average remaining contractual term	1 year 6 months
Current liabilities	$ 23
Stock-based compensation expense	$ 23

Common Shares - Weighted Averag

Common Shares - Weighted Average (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Common Shares
Basic common shares	99,738,461	98,627,255
Diluted common shares	99,738,461	98,627,255

Common Shares - Anti-dilutive (

Common Shares - Anti-dilutive (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares outstanding	1,319,149	1,144,500
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares outstanding	1,002,670	1,567,907
Warrants
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 (

Common Shares - ATM Agreement (Details) - At-The-Market Offering Agreement [Member] - H. C. Wainwright And Co., LLC [Member] - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2017	Dec. 31, 2018	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	$ 0

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income/(Loss) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Accumulated other comprehensive income/(loss)
Balances, beginning of period	$ 40,525
Balances, end of period	29,083
Accumulated other comprehensive income/(loss) net of tax
Balances, beginning of period	40,525
Balances, end of period	29,083
Accumulated Other Comprehensive Income/(Loss)
Accumulated other comprehensive income/(loss)
Balances, beginning of period	15
Balances, end of period	(2)
Accumulated other comprehensive income/(loss) net of tax
Balances, beginning of period	15
Balances, end of period	(2)
Accumulated Other Comprehensive Income/(Loss) | Accounting Standards Update 2016-01
Accumulated other comprehensive income/(loss)
Cumulative adjustment related to Accounting Standard Update 2016-01	2
Accumulated due to realization of gain on marketable securities
Accumulated other comprehensive income/(loss)
Other comprehensive gain due to change in fair market value of marketable securities during period before reclassifications, before tax	(17)
Accumulated other comprehensive income/(loss) net of tax
Other comprehensive gain due to change in fair market value of marketable securities during period before reclassifications, net of tax	(14)
Accumulated other comprehensive income after tax
Accumulated other comprehensive income/(loss)
Balances, beginning of period	14
Accumulated other comprehensive income/(loss) net of tax
Balances, beginning of period	$ 14

Commitments And Contingencies (

Commitments And Contingencies (Details) - Mt Todd, Australia $ in Thousands	12 Months Ended
	Dec. 31, 2018AUD ($)
Loss Contingencies [Line Items]
Percentage of ownership in project	100.00%
Scenario, Plan
Loss Contingencies [Line Items]
Percentage of ownership in project	90.00%
Scenario, Plan | Jawoyn Association Aboriginal Corporation
Loss Contingencies [Line Items]
Percentage of ownership in project	10.00%
Percentage of royalty on gold	1.00%
Percentage of royalty on other metals	1.00%
Minimum payment per year	$ 50

Fair Value Accounting (Details)

Fair Value Accounting (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value Accounting
Other investments	$ 5,462	$ 3,746
Fair Value Transfers Between Levels		0
Midas Gold Shares
Fair Value Accounting
Other investments	5,462	3,746	$ 4,994
Recurring | Marketable Securities (Other Than Midas Gold Shares)
Fair Value Accounting
Marketable securities		90
Recurring | Midas Gold Shares
Fair Value Accounting
Other investments	5,462	3,746
Recurring | Fair Value, Inputs, Level 1 | Marketable Securities (Other Than Midas Gold Shares)
Fair Value Accounting
Marketable securities		90
Recurring | Fair Value, Inputs, Level 1 | Midas Gold Shares
Fair Value Accounting
Other investments	5,462	3,746
Non-recurring | Used mill equipment, Canada
Fair Value Accounting
Used mill equipment (non-recurring)	5,500	6,500
Non-recurring | Fair Value, Inputs, Level 3 | Used mill equipment, Canada
Fair Value Accounting
Used mill equipment (non-recurring)	$ 5,500	$ 6,500

Income Taxes - Source of Income

Income Taxes - Source of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income (loss) before income taxes, total	$ (8,714)	$ (12,035)
U.S.
Income (loss) before income taxes, domestic	(646)	(2,477)
Canada
Income (loss) before income taxes, foreign	(2,288)	(2,119)
Other Foreign
Income (loss) before income taxes, foreign	$ (5,780)	$ (7,439)

Income Taxes - Deferred Tax Exp

Income Taxes - Deferred Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
U.S.
Current income tax expense (benefit)	$ 0	$ 0
Deferred income tax expense (benefit)	0	0
Canada
Current income tax expense (benefit)	0	0
Deferred income tax expense (benefit)	0	0
Other Foreign
Deferred income tax expense (benefit)	$ 0	$ 0

Income Taxes - Rate Reconciliat

Income Taxes - Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Income taxed at statutory rates	$ (2,125)	$ (4,212)
Stock-based compensation	79	46
Other adjustments	5	(87)
Prior year provision to actual adjustments	(2,867)	108
Change in US tax rate		2,487
Differences in tax rates	(339)	563
Effect of foreign exchange	(6)	(99)
Change in valuation allowance	$ 5,253	$ 1,194

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets/Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Components of Deferred Tax Assets and Liabilities [Abstract]
Excess tax basis over book basis of property, plant, and equipment	$ 7,488	$ 7,488
Marketable securities	667	771
Operating loss carryforwards	34,052	28,530
Capital loss carryforwards	13,276	13,470
Other	2,031	1,848
Total future tax assets	57,514	52,107
Valuation allowance for future tax assets	(56,659)	(51,406)
Total income tax assets	855	701
Other investments	855	701
Total deferred income tax liabilities	$ 855	$ 701

Income Taxes - Operating Loss C

Income Taxes - Operating Loss Carryforward Expirations (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Operating Loss Carryforwards [Line Items]
Total	$ (75,353)
Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(46,980)
Capital loss carryforwards	53,883
U.S.
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	2,395
Expiring net operating loss carryforwards	(20,770)
Mexico
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(7,508)
Barbados
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(95)
Australia
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	46,600
Tax Year 2021
Operating Loss Carryforwards [Line Items]
Total	(20)
Tax Year 2021 | Barbados
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(20)
Tax Year 2022
Operating Loss Carryforwards [Line Items]
Total	(6,215)
Tax Year 2022 | Mexico
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(6,184)
Tax Year 2022 | Barbados
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(31)
Tax Year 2023
Operating Loss Carryforwards [Line Items]
Total	(369)
Tax Year 2023 | Mexico
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(347)
Tax Year 2023 | Barbados
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(22)
Tax Year 2024
Operating Loss Carryforwards [Line Items]
Total	(4)
Tax Year 2024 | Barbados
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(4)
Tax Year 2025
Operating Loss Carryforwards [Line Items]
Total	(80)
Tax Year 2025 | Mexico
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(74)
Tax Year 2025 | Barbados
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(6)
Tax Year 2026
Operating Loss Carryforwards [Line Items]
Total	(1,730)
Tax Year 2026 | Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(1,027)
Tax Year 2026 | Mexico
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(697)
Tax Year 2026 | Barbados
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(6)
Tax Year 2027
Operating Loss Carryforwards [Line Items]
Total	(853)
Tax Year 2027 | Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(847)
Tax Year 2027 | Barbados
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(6)
Tax Year 2028
Operating Loss Carryforwards [Line Items]
Total	(6,738)
Tax Year 2028 | Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(5,245)
Tax Year 2028 | U.S.
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(1,287)
Tax Year 2028 | Mexico
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(206)
Tax Year 2029
Operating Loss Carryforwards [Line Items]
Total	(5,741)
Tax Year 2029 | Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(4,022)
Tax Year 2029 | U.S.
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(1,719)
Tax Year 2030
Operating Loss Carryforwards [Line Items]
Total	(7,002)
Tax Year 2030 | Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(5,032)
Tax Year 2030 | U.S.
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(1,970)
Tax Year 2031
Operating Loss Carryforwards [Line Items]
Total	(5,633)
Tax Year 2031 | Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(3,806)
Tax Year 2031 | U.S.
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(1,827)
Tax Year 2032
Operating Loss Carryforwards [Line Items]
Total	(9,804)
Tax Year 2032 | Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(6,397)
Tax Year 2032 | U.S.
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(3,407)
Tax Year 2033
Operating Loss Carryforwards [Line Items]
Total	(8,399)
Tax Year 2033 | Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(6,076)
Tax Year 2033 | U.S.
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(2,323)
Tax Year 2034
Operating Loss Carryforwards [Line Items]
Total	(7,518)
Tax Year 2034 | Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(4,420)
Tax Year 2034 | U.S.
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(3,098)
Tax year 2035
Operating Loss Carryforwards [Line Items]
Total	(3,731)
Tax year 2035 | Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(3,729)
Tax year 2035 | U.S.
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(2)
Tax Year 2036
Operating Loss Carryforwards [Line Items]
Total	(5,454)
Tax Year 2036 | Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(2,799)
Tax Year 2036 | U.S.
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(2,655)
Tax Year 2037
Operating Loss Carryforwards [Line Items]
Total	(4,398)
Tax Year 2037 | Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	(1,916)
Tax Year 2037 | U.S.
Operating Loss Carryforwards [Line Items]
Expiring net operating loss carryforwards	(2,482)
Tax Year 2038
Operating Loss Carryforwards [Line Items]
Total	(1,664)
Tax Year 2038 | Canada
Operating Loss Carryforwards [Line Items]
Expiring noncapital loss carryforwards	$ (1,664)

Income Taxes - Uncertainty (Det

Income Taxes - Uncertainty (Details) $ in Thousands	Dec. 31, 2018USD ($)
Income Taxes
Unrecognized tax positions	$ 0

Geographic And Segment Inform_2

Geographic And Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)segment	Dec. 31, 2017USD ($)
Geographic and Segment information
Number of reportable segments | segment	1
Revenues | $	$ 0	$ 0