Business and Summary of Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and company formation	Solitario Zinc Corp. (“Solitario,” or the “Company”) is an exploration stage company as defined in Industry Guide 7, as issued by the United States Securities and Exchange Commission (“SEC”). Solitario was incorporated in the state of Colorado on November 15, 1984 as a wholly owned subsidiary of Crown Resources Corporation ("Crown"). In July 1994, Solitario became a publicly traded company on the Toronto Stock Exchange (the "TSX") through its initial public offering. Solitario has been actively involved in mineral exploration since 1993. Solitario’s primary business is to acquire exploration mineral properties and/or discover economic deposits on its mineral properties and advance these deposits, either on its own or through joint ventures, up to the development stage. At that point, or sometime prior to that point, Solitario would likely attempt to sell its mineral properties, pursue their development either on its own, or through a joint venture with a partner that has expertise in mining operations, or create a royalty with a third party that continues to advance the property. Solitario is primarily focused on the acquisition and exploration of zinc-related exploration mineral properties, in addition to focusing on its mineral exploration properties and the evaluation of mineral properties for acquisition. Solitario also evaluates potential strategic corporate transactions as a means to acquire an interest in new precious and base metal properties and assets with exploration potential as well as other potential corporate transactions and business combinations that Solitario determines to be favorable to Solitario. Solitario has previously recorded revenue in the past from the sale of mineral properties, including the sale of certain mineral royalty properties in January 2019, discussed below. Revenues and / or proceeds from the sale or joint venture of properties or assets have not been a consistent annual source of cash and would only occur in the future, if at all, on an infrequent basis. Solitario currently considers its carried interest in the Florida Canyon project and its interest in the Lik project to be its core mineral property assets. Nexa Resources, Ltd. (“Nexa”), Solitario’s joint venture partner, is continuing the exploration and furtherance of the Florida Canyon project and Solitario is monitoring progress at Florida Canyon. Solitario is working with its 50% joint venture partner, Teck American Incorporated, a wholly owned subsidiary of Teck Resources Limited (both companies are referred to as “Teck”), in the Lik deposit to further the exploration of the Lik project, and to evaluate potential development plans for the Lik project. As of December 31, 2020 and 2019, Solitario has significant balances of cash and short-term investments that Solitario anticipates using, in part, to further the development of the Florida Canyon project and the Lik project and to potentially acquire additional mineral property assets. During 2020 Solitario acquired an option to buy a 100% interest in the non-producing Gold Coin project in Arizona and recorded mineral property of $17,000 for its initial investment in the Gold Coin project. All future expenditures for the Gold Coin project will be expensed as incurred as exploration expense until such time Solitario establishes proven and probable reserves, which cannot be assured. If Solitario establishes proven and probable reserves, subsequent expenditures would be evaluated to determine appropriate accounting treatment. The fluctuations in precious metal and other commodity prices have contributed to a challenging environment for mineral exploration and development, which has created opportunities as well as challenges for the potential acquisition of early-stage and advanced mineral exploration projects or other related assets at potentially attractive terms.
Financial reporting	The consolidated financial statements include the accounts of Solitario and its wholly owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. The consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America ("generally accepted accounting principles") and are expressed in US dollars.
Revenue recognition	Solitario has recorded revenue from the sale of exploration mineral properties and joint venture property payments. Solitario’s policy is to recognize revenue from the sale of its exploration mineral properties (those without reserves) on a property-by-property basis, computed as the cash received and / or collectable receivables less any capitalized cost. Payments received for the sale of exploration property interests that are less than the properties cost are recorded as a reduction of the related property's capitalized cost. In addition, Solitario’s policy is to recognize revenue on any receipts of joint venture property payments in excess of its capitalized costs on a property that Solitario may lease to another mining company. Solitario has recognized revenue during 2019 of $408,000 related to the Royalty Sale, discussed below, with no similar item during 2020. Solitario expects any property sales in the future to be on an infrequent basis. Prior to the Royalty Sale, the last proceeds from joint venture property payments was in 2018 from the sale of its royalty in the Yanacocha property. Solitario does not expect to record joint venture property payments on any of its currently held properties for the foreseeable future. Historically, Solitario’s revenues have been infrequent and significant individual transactions have only been from sales to well known or vetted mining companies. Solitario has never had a return on any of its sales recorded as revenue in its history and does not anticipate it will recognize any estimated returns on its current or future recorded revenues.
Use of estimates	The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Some of the more significant estimates included in the preparation of Solitario's financial statements pertain to: (i) the recoverability of mineral properties related to its mineral exploration properties and their future exploration potential; (ii) the fair value of stock option grants to employees; (iii) the ability of Solitario to realize its deferred tax assets; and (iv) Solitario's investment in marketable equity securities. In performing its activities, Solitario has incurred certain costs for mineral properties. The recovery of these costs is ultimately dependent upon the sale of mineral property interests or the development of economically recoverable ore reserves and the ability of Solitario to obtain the necessary permits and financing to successfully place the properties into production, and upon future profitable operations, none of which is assured.
Cash and cash equivalents	Cash equivalents include investments in highly liquid money-market securities with original maturities of three months or less when purchased. At December 31, 2020, approximately $595,000 of Solitario’s cash and cash equivalents are held in brokerage accounts and foreign banks, which are not covered under the Federal Deposit Insurance Corporation (“FDIC”) rules for the United States.
Short-term investments	At December 31, 2020, Solitario has United States Treasury securities (“USTS”) with maturities of 30 days to one year, recorded at their fair value of $3,989,000 compared to USTS recorded at their fair value of $6,829,000 at December 31, 2019. Solitario also holds FDIC insured bank certificates of deposit (“CD’s”) with face values between $100,000 and $250,000 and maturities of two months to 17 months, which are recorded at their fair value of $1,809,000 at December 31, 2020. Solitario held no CD’s at December 31, 2019. Solitario’s short-term investments are recorded at their fair value based upon quoted market prices. The short-term investments are highly liquid and may be sold in their entirety at any time at their quoted market price and are classified as a current asset.
Mineral properties	Solitario expenses all exploration costs incurred on its mineral properties prior to the establishment of proven and probable reserves through the completion of a feasibility study. Initial acquisition costs of its mineral properties are capitalized. Solitario regularly performs evaluations of its investment in mineral properties to assess the recoverability and/or the residual value of its investments in these assets. All long-lived assets are reviewed for impairment whenever events or circumstances change which indicate the carrying amount of an asset may not be recoverable, utilizing established guidelines based upon undiscounted future net cash flows from the asset or upon the determination that certain exploration properties do not have sufficient potential for economic mineralization.
Derivative instruments	Solitario accounts for its derivative instruments in accordance with ASC 815, "Accounting for Derivative Instruments and Hedging Activities" (“ASC 815”). During 2019, Solitario acquired certain Vendetta Mining Corp. (“Vendetta”) units, which included Vendetta Warrants (defined below). Changes in fair value of the Vendetta Warrants are recognized in the statements of operations in the period of change as gain or loss on derivative instruments. Solitario has entered into covered calls from time to time on its investment in Kinross marketable equity securities. Solitario has not designated its covered calls as hedging instruments and any changes in the fair value of the covered calls are recognized in the statements of operations in the period of the change as gain or loss on derivative instruments.
Fair value	Financial Accounting Standards Board ASC 820, “Fair Value Measurements and Disclosures” (“ASC 820”) establishes a framework for measuring fair value and requires enhanced disclosures about fair value measurements. ASC 820 clarifies that fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Solitario's short-term investments in USTS, its marketable equity securities and any covered call options against those marketable equity securities are carried at their estimated fair value based on quoted market prices. See Note 10, “Fair Value of Financial Instruments,” below.
Marketable equity securities	Solitario's investments in marketable equity securities are carried at fair value, which is based upon quoted prices of the securities owned. Solitario records investments in marketable equity securities for investments in publicly traded marketable equity securities for which it does not exercise significant control and where Solitario has no representation on the board of directors of those companies and exercises no control over the management of those companies. The cost of marketable equity securities sold is determined by the specific identification method. Changes in fair value are recorded as unrealized gain or loss in the consolidated statement of operations.
Foreign exchange	The United States dollar is the functional currency for all of Solitario's foreign subsidiaries. Although Solitario's South American exploration activities during 2020 and 2019 were conducted primarily in Peru, a portion of the payments for the land, leasehold and exploration agreements as well as certain exploration activities are denominated in United States dollars. Foreign currency gains and losses are included in the results of operations in the period in which they occur.
Income taxes	Solitario accounts for income taxes in accordance with ASC 740, “Accounting for Income Taxes” (“ASC 740”). Under ASC 740, income taxes are provided for the tax effects of transactions reported in the financial statements and consist of taxes currently due plus deferred taxes related to certain income and expenses recognized in different periods for financial and income tax reporting purposes. Deferred tax assets and liabilities represent the future tax return consequences of those differences, which will either be taxable or deductible when the assets and liabilities are recovered or settled. Deferred taxes are also recognized for operating losses and tax credits that are available to offset future taxable income and income taxes, respectively. A valuation allowance is provided if it is more likely than not that some portion or all of the deferred tax assets will not be realized.
Accounting for uncertainty in income taxes	ASC 740 clarifies the accounting for uncertainty in income taxes recognized in a company's financial statements. ASC 740 prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. ASC 740 also provides guidance on derecognition, classification, interest and penalties, accounting in interim periods, disclosure, and transition. ASC 740 provides that a company's tax position will be considered settled if the taxing authority has completed its examination, the company does not plan to appeal, and it is remote that the taxing authority would reexamine the tax position in the future. These provisions of ASC 740 had no effect on Solitario's financial position or results of operations. See Note 7, “Income Taxes,” below.
Earnings per share	The calculation of basic and diluted earnings (loss) per share is based on the weighted average number of shares of common stock outstanding during the years ended December 31, 2020 and 2019. Potentially dilutive shares, consisting of outstanding common stock options of 5,558,000 and 4,373,000, respectively, exercisable for Solitario common shares were excluded from the calculation of diluted loss per share for the year ended December 31, 2020 and 2019 because the effects were anti-dilutive.
Employee stock compensation and incentive plans	Solitario classifies all of its stock options as equity options in accordance with the provisions of ASC 718, “Compensation – Stock Compensation.” See Note 12, “Employee Stock Compensation Plans,” below.
Risk and uncertainties	Solitario faces risks related to health epidemics and other outbreaks of communicable diseases, which could significantly disrupt its operations and may materially and adversely affect its business and financial conditions. Solitario’s business could be adversely impacted by the effects of the coronavirus (“COVID-19”) or other epidemics or pandemics. Solitario has recommended all of its employees and contractors follow government guidelines for health and safety policies for employees and contractors, including encouraging tele-commuting and working from home where possible. Solitario has evaluated the effects of COVID-19 on its operations and taken pro-active steps to address the impacts on its operations, including reducing costs, in response to the economic uncertainty associated with potential risks from COVID-19. These reductions include implementing salary reductions and evaluation and reduction in certain planned 2020 exploration programs through its joint venture partners at the Florida Canyon and Lik exploration projects. Also, Solitairo has evaluated the potential impacts on its ability to access future traditional funding sources on the same or reasonably similar terms as in past periods. Solitario will continue to monitor the effects of COVID-19 on its operations, financial condition and liquidity. However, the extent to which COVID-19 impacts Solitario’s business, including our exploration and other activities and the market for its securities, will depend on future developments, which are highly uncertain and cannot be predicted at this time, and include the duration, severity and scope of the outbreak and the actions taken to contain or treat the coronavirus outbreak.
Recent accounting pronouncements	Recently adopted accounting pronouncements The FASB issued ASU No. 2018-13, Fair Value Measurement (topic 820) Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement (“ASU 2018-13”). The amendments in ASU 2018-13 simplified certain disclosures regarding fair value measurements including the amount and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy and the policy for timing of transfers between levels and the valuation processes for Level 3 fair value measurements. In addition, ASU 2018-13 requires disclosures regarding unrealized gains and losses included in other comprehensive income and the range and weighted average of significant unobservable inputs used in Level 3 fair value measurements. Solitario adopted ASU 2018-13 effective January 1, 2020. The adoption of ASU 2018-13 did not have an impact on Solitario’s consolidated financial position or results of operations. The FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurements of Credit Losses on Financial Statements (“ASU 2016-13”). Among other things, these amendments require the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better inform their credit loss estimates. Solitario adopted ASU No. 2016-13 effective January 1, 2020. The adoption of ASU 2016-13 did not have an impact on its consolidated financial position or results of operations. Recently issued accounting pronouncements The SEC has adopted amendments to its disclosure rules to modernize the mineral property disclosure requirements for issuers whose securities are registered with the SEC. These amendments became effective February 25, 2019 (the “SEC Modernization Rules”) and, following a two-year transition period, the SEC Modernization Rules will replace the historical property disclosure requirements for mining registrants that are included in SEC Industry Guide 7. Under the SEC Modernization Rules, consistent with global standards as embodied by the Committee for Reserves International Reporting Standards (“CRIRSCO”), registrants will be required to disclose specified information concerning mineral resources that have been identified on one or more of its mineral properties. Consistent with CRIRSCO standards the SEC Modernization Rules have added definitions to recognize “Measured Mineral Resources”, “Indicated Mineral Resources” and “Inferred Mineral Resources.” The Company is not required to provide disclosure on its mineral properties under the SEC Modernization Rules until its fiscal year beginning January 1, 2021. Upon adoption of the SEC Modernization Rules, among other requirements, the Company will be required to report its mineral resources, if any, as Measured, Indicated or Inferred Mineral Resources in accordance with the SEC Modernization Rules. This will allow investors to evaluate the Company’s resources on a comparable basis with other mining and exploration issuers registered with the SEC. In addition, the SEC Modernization Rules will require the Company to disclose exploration results, mineral reserves, if any, and mineral resources based upon information and supporting documentation prepared by a mining expert (the “qualified person”). The SEC Modernization Rules will require the Company to obtain a dated and signed technical report summary from the qualified person identifying and summarizing the information reviewed and conclusions reached by the qualified person(s) about the mineral resources or reserves for each mineral property. The Company is currently evaluating the requirements under the SEC Modernization Rules and has not determined what effect adoption will have on its consolidated financial statements and disclosures.

Business and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Solitario Zinc Corp. (“Solitario,” or the “Company”) is an exploration stage company as defined in Industry Guide 7, as issued by the United States Securities and Exchange Commission (“SEC”). Solitario was incorporated in the state of Colorado on November 15, 1984 as a wholly owned subsidiary of Crown Resources Corporation ("Crown"). In July 1994, Solitario became a publicly traded company on the Toronto Stock Exchange (the "TSX") through its initial public offering. Solitario has been actively involved in mineral exploration since 1993. Solitario’s primary business is to acquire exploration mineral properties and/or discover economic deposits on its mineral properties and advance these deposits, either on its own or through joint ventures, up to the development stage. At that point, or sometime prior to that point, Solitario would likely attempt to sell its mineral properties, pursue their development either on its own, or through a joint venture with a partner that has expertise in mining operations, or create a royalty with a third party that continues to advance the property. Solitario is primarily focused on the acquisition and exploration of zinc-related exploration mineral properties, in addition to focusing on its mineral exploration properties and the evaluation of mineral properties for acquisition. Solitario also evaluates potential strategic corporate transactions as a means to acquire an interest in new precious and base metal properties and assets with exploration potential as well as other potential corporate transactions and business combinations that Solitario determines to be favorable to Solitario.

Solitario has previously recorded revenue in the past from the sale of mineral properties, including the sale of certain mineral royalty properties in January 2019, discussed below. Revenues and / or proceeds from the sale or joint venture of properties or assets have not been a consistent annual source of cash and would only occur in the future, if at all, on an infrequent basis.

Solitario currently considers its carried interest in the Florida Canyon project and its interest in the Lik project to be its core mineral property assets. Nexa Resources, Ltd. (“Nexa”), Solitario’s joint venture partner, is continuing the exploration and furtherance of the Florida Canyon project and Solitario is monitoring progress at Florida Canyon. Solitario is working with its 50% joint venture partner, Teck American Incorporated, a wholly owned subsidiary of Teck Resources Limited (both companies are referred to as “Teck”), in the Lik deposit to further the exploration of the Lik project, and to evaluate potential development plans for the Lik project.

As of December 31, 2020 and 2019, Solitario has significant balances of cash and short-term investments that Solitario anticipates using, in part, to further the development of the Florida Canyon project and the Lik project and to potentially acquire additional mineral property assets. During 2020 Solitario acquired an option to buy a 100% interest in the non-producing Gold Coin project in Arizona and recorded mineral property of $17,000 for its initial investment in the Gold Coin project. All future expenditures for the Gold Coin project will be expensed as incurred as exploration expense until such time Solitario establishes proven and probable reserves, which cannot be assured. If Solitario establishes proven and probable reserves, subsequent expenditures would be evaluated to determine appropriate accounting treatment. The fluctuations in precious metal and other commodity prices have contributed to a challenging environment for mineral exploration and development, which has created opportunities as well as challenges for the potential acquisition of early-stage and advanced mineral exploration projects or other related assets at potentially attractive terms.

Financial reporting

The consolidated financial statements include the accounts of Solitario and its wholly owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. The consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America ("generally accepted accounting principles") and are expressed in US dollars.

Revenue recognition

Solitario has recorded revenue from the sale of exploration mineral properties and joint venture property payments. Solitario’s policy is to recognize revenue from the sale of its exploration mineral properties (those without reserves) on a property-by-property basis, computed as the cash received and / or collectable receivables less any capitalized cost. Payments received for the sale of exploration property interests that are less than the properties cost are recorded as a reduction of the related property's capitalized cost. In addition, Solitario’s policy is to recognize revenue on any receipts of joint venture property payments in excess of its capitalized costs on a property that Solitario may lease to another mining company.

Solitario has recognized revenue during 2019 of $408,000 related to the Royalty Sale, discussed below, with no similar item during 2020. Solitario expects any property sales in the future to be on an infrequent basis. Prior to the Royalty Sale, the last proceeds from joint venture property payments was in 2018 from the sale of its royalty in the Yanacocha property. Solitario does not expect to record joint venture property payments on any of its currently held properties for the foreseeable future. Historically, Solitario’s revenues have been infrequent and significant individual transactions have only been from sales to well known or vetted mining companies. Solitario has never had a return on any of its sales recorded as revenue in its history and does not anticipate it will recognize any estimated returns on its current or future recorded revenues.

Use of estimates

The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Some of the more significant estimates included in the preparation of Solitario's financial statements pertain to: (i) the recoverability of mineral properties related to its mineral exploration properties and their future exploration potential; (ii) the fair value of stock option grants to employees; (iii) the ability of Solitario to realize its deferred tax assets; and (iv) Solitario's investment in marketable equity securities.

In performing its activities, Solitario has incurred certain costs for mineral properties. The recovery of these costs is ultimately dependent upon the sale of mineral property interests or the development of economically recoverable ore reserves and the ability of Solitario to obtain the necessary permits and financing to successfully place the properties into production, and upon future profitable operations, none of which is assured.

Cash and cash equivalents

Cash equivalents include investments in highly liquid money-market securities with original maturities of three months or less when purchased. At December 31, 2020, approximately $595,000 of Solitario’s cash and cash equivalents are held in brokerage accounts and foreign banks, which are not covered under the Federal Deposit Insurance Corporation (“FDIC”) rules for the United States.

Short-term investments

At December 31, 2020, Solitario has United States Treasury securities (“USTS”) with maturities of 30 days to one year, recorded at their fair value of $3,989,000 compared to USTS recorded at their fair value of $6,829,000 at December 31, 2019. Solitario also holds FDIC insured bank certificates of deposit (“CD’s”) with face values between $100,000 and $250,000 and maturities of two months to 17 months, which are recorded at their fair value of $1,809,000 at December 31, 2020. Solitario held no CD’s at December 31, 2019. Solitario’s short-term investments are recorded at their fair value based upon quoted market prices. The short-term investments are highly liquid and may be sold in their entirety at any time at their quoted market price and are classified as a current asset.

Mineral properties

Solitario expenses all exploration costs incurred on its mineral properties prior to the establishment of proven and probable reserves through the completion of a feasibility study. Initial acquisition costs of its mineral properties are capitalized. Solitario regularly performs evaluations of its investment in mineral properties to assess the recoverability and/or the residual value of its investments in these assets. All long-lived assets are reviewed for impairment whenever events or circumstances change which indicate the carrying amount of an asset may not be recoverable, utilizing established guidelines based upon undiscounted future net cash flows from the asset or upon the determination that certain exploration properties do not have sufficient potential for economic mineralization.

Derivative instruments

Solitario accounts for its derivative instruments in accordance with ASC 815, "Accounting for Derivative Instruments and Hedging Activities" (“ASC 815”). During 2019, Solitario acquired certain Vendetta Mining Corp. (“Vendetta”) units, which included Vendetta Warrants (defined below). Changes in fair value of the Vendetta Warrants are recognized in the statements of operations in the period of change as gain or loss on derivative instruments. Solitario has entered into covered calls from time to time on its investment in Kinross marketable equity securities. Solitario has not designated its covered calls as hedging instruments and any changes in the fair value of the covered calls are recognized in the statements of operations in the period of the change as gain or loss on derivative instruments.

Fair value

Financial Accounting Standards Board ASC 820, “Fair Value Measurements and Disclosures” (“ASC 820”) establishes a framework for measuring fair value and requires enhanced disclosures about fair value measurements. ASC 820 clarifies that fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Solitario's short-term investments in USTS, its marketable equity securities and any covered call options against those marketable equity securities are carried at their estimated fair value based on quoted market prices. See Note 10, “Fair Value of Financial Instruments,” below.

Marketable equity securities

Solitario's investments in marketable equity securities are carried at fair value, which is based upon quoted prices of the securities owned. Solitario records investments in marketable equity securities for investments in publicly traded marketable equity securities for which it does not exercise significant control and where Solitario has no representation on the board of directors of those companies and exercises no control over the management of those companies. The cost of marketable equity securities sold is determined by the specific identification method. Changes in fair value are recorded as unrealized gain or loss in the consolidated statement of operations.

Foreign exchange

The United States dollar is the functional currency for all of Solitario's foreign subsidiaries. Although Solitario's South American exploration activities during 2020 and 2019 were conducted primarily in Peru, a portion of the payments for the land, leasehold and exploration agreements as well as certain exploration activities are denominated in United States dollars. Foreign currency gains and losses are included in the results of operations in the period in which they occur.

Income taxes

Solitario accounts for income taxes in accordance with ASC 740, “Accounting for Income Taxes” (“ASC 740”). Under ASC 740, income taxes are provided for the tax effects of transactions reported in the financial statements and consist of taxes currently due plus deferred taxes related to certain income and expenses recognized in different periods for financial and income tax reporting purposes. Deferred tax assets and liabilities represent the future tax return consequences of those differences, which will either be taxable or deductible when the assets and liabilities are recovered or settled. Deferred taxes are also recognized for operating losses and tax credits that are available to offset future taxable income and income taxes, respectively. A valuation allowance is provided if it is more likely than not that some portion or all of the deferred tax assets will not be realized.

Accounting for uncertainty in income taxes

ASC 740 clarifies the accounting for uncertainty in income taxes recognized in a company's financial statements. ASC 740 prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. ASC 740 also provides guidance on derecognition, classification, interest and penalties, accounting in interim periods, disclosure, and transition. ASC 740 provides that a company's tax position will be considered settled if the taxing authority has completed its examination, the company does not plan to appeal, and it is remote that the taxing authority would reexamine the tax position in the future. These provisions of ASC 740 had no effect on Solitario's financial position or results of operations. See Note 7, “Income Taxes,” below.

Earnings per share

The calculation of basic and diluted earnings (loss) per share is based on the weighted average number of shares of common stock outstanding during the years ended December 31, 2020 and 2019. Potentially dilutive shares, consisting of outstanding common stock options of 5,558,000 and 4,373,000, respectively, exercisable for Solitario common shares were excluded from the calculation of diluted loss per share for the year ended December 31, 2020 and 2019 because the effects were anti-dilutive.

Employee stock compensation and incentive plans

Solitario classifies all of its stock options as equity options in accordance with the provisions of ASC 718, “Compensation – Stock Compensation.” See Note 12, “Employee Stock Compensation Plans,” below.

Risk and uncertainties

Solitario faces risks related to health epidemics and other outbreaks of communicable diseases, which could significantly disrupt its operations and may materially and adversely affect its business and financial conditions.

Solitario’s business could be adversely impacted by the effects of the coronavirus (“COVID-19”) or other epidemics or pandemics. Solitario has recommended all of its employees and contractors follow government guidelines for health and safety policies for employees and contractors, including encouraging tele-commuting and working from home where possible. Solitario has evaluated the effects of COVID-19 on its operations and taken pro-active steps to address the impacts on its operations, including reducing costs, in response to the economic uncertainty associated with potential risks from COVID-19. These reductions include implementing salary reductions and evaluation and reduction in certain planned 2020 exploration programs through its joint venture partners at the Florida Canyon and Lik exploration projects. Also, Solitairo has evaluated the potential impacts on its ability to access future traditional funding sources on the same or reasonably similar terms as in past periods. Solitario will continue to monitor the effects of COVID-19 on its operations, financial condition and liquidity. However, the extent to which COVID-19 impacts Solitario’s business, including our exploration and other activities and the market for its securities, will depend on future developments, which are highly uncertain and cannot be predicted at this time, and include the duration, severity and scope of the outbreak and the actions taken to contain or treat the coronavirus outbreak.

Recent accounting pronouncements

Recently adopted accounting pronouncements

The FASB issued ASU No. 2018-13, Fair Value Measurement (topic 820) Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement (“ASU 2018-13”). The amendments in ASU 2018-13 simplified certain disclosures regarding fair value measurements including the amount and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy and the policy for timing of transfers between levels and the valuation processes for Level 3 fair value measurements. In addition, ASU 2018-13 requires disclosures regarding unrealized gains and losses included in other comprehensive income and the range and weighted average of significant unobservable inputs used in Level 3 fair value measurements. Solitario adopted ASU 2018-13 effective January 1, 2020. The adoption of ASU 2018-13 did not have an impact on Solitario’s consolidated financial position or results of operations.

The FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurements of Credit Losses on Financial Statements (“ASU 2016-13”). Among other things, these amendments require the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better inform their credit loss estimates. Solitario adopted ASU No. 2016-13 effective January 1, 2020. The adoption of ASU 2016-13 did not have an impact on its consolidated financial position or results of operations.

Recently issued accounting pronouncements

The SEC has adopted amendments to its disclosure rules to modernize the mineral property disclosure requirements for issuers whose securities are registered with the SEC. These amendments became effective February 25, 2019 (the “SEC Modernization Rules”) and, following a two-year transition period, the SEC Modernization Rules will replace the historical property disclosure requirements for mining registrants that are included in SEC Industry Guide 7. Under the SEC Modernization Rules, consistent with global standards as embodied by the Committee for Reserves International Reporting Standards (“CRIRSCO”), registrants will be required to disclose specified information concerning mineral resources that have been identified on one or more of its mineral properties. Consistent with CRIRSCO standards the SEC Modernization Rules have added definitions to recognize “Measured Mineral Resources”, “Indicated Mineral Resources” and “Inferred Mineral Resources.” The Company is not required to provide disclosure on its mineral properties under the SEC Modernization Rules until its fiscal year beginning January 1, 2021.

Upon adoption of the SEC Modernization Rules, among other requirements, the Company will be required to report its mineral resources, if any, as Measured, Indicated or Inferred Mineral Resources in accordance with the SEC Modernization Rules. This will allow investors to evaluate the Company’s resources on a comparable basis with other mining and exploration issuers registered with the SEC. In addition, the SEC Modernization Rules will require the Company to disclose exploration results, mineral reserves, if any, and mineral resources based upon information and supporting documentation prepared by a mining expert (the “qualified person”). The SEC Modernization Rules will require the Company to obtain a dated and signed technical report summary from the qualified person identifying and summarizing the information reviewed and conclusions reached by the qualified person(s) about the mineral resources or reserves for each mineral property. The Company is currently evaluating the requirements under the SEC Modernization Rules and has not determined what effect adoption will have on its consolidated financial statements and disclosures.