| Summary of Significant Accounting Policies (Policies) | 12 Months Ended | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Dec. 31, 2013 | |||||||||||
| Accounting Policies [Abstract] | |||||||||||
| Basis of presentation | Basis of  presentation These financial  statements have been prepared by management in accordance with  United States generally accepted accounting principles (“US  GAAP”) and include all of the assets, liabilities and  expenses of the Company and its wholly-owned subsidiaries Ur-Energy  USA Inc.; NFU Wyoming, LLC; Lost Creek ISR, LLC; NFUR Bootheel,  LLC; Hauber Project LLC; NFUR Hauber, LLC; and (as of December 20,  2013) Pathfinder Mines Corporation.   All inter-company balances and transactions have been eliminated  upon consolidation.   Ur-Energy Inc. and its wholly-owned subsidiaries are collectively  referred to herein as the “Company.” | ||||||||||
| Functional currency and presentation currency | 
Functional  currency and  presentation currency 
 The Company changed  its functional currency prospectively, beginning January 1, 2013,  from the Canadian dollar to the U.S. dollar with respect to its  operations in the United States. The change in functional currency  had a significant impact on the Company’s consolidated  financial statements as most of the non-current assets of the  Company are situated in the United States and were previously  accounted for using the Canadian dollar as the functional  currency. As  of January 1, 2013, the Company recorded a cumulative transaction  adjustment (“CTA”) of approximately $6.2  million for this change, which is shown in the consolidated  statement of shareholders’ equity. The functional  currency for Canadian operations will remain the Canadian  dollar.   They will be consolidated with the U.S. cost basis balances using  the spot rate for assets and liabilities, the historical cost rates  for shareholders’ equity transactions and the average rate  for all operating revenues and expenses.  Additional  translation adjustments will result from the change in  consolidation methods as prescribed by US GAAP where there are  multiple functional currencies reflected in consolidated financial  statements.   These adjustments will not be included in determining net income,  but will be reported separately and accumulated in other  comprehensive income. In  addition as a result of losing its foreign private issuer status,  the Company changed its presentational currency from the Canadian  dollar to U.S. dollars. As a result, comparative information has  been changed. The effects of doing so are not significant because  the Canadian and U.S. dollars were close to par at December 31,  2012. | ||||||||||
| Exploration Stage |   Exploration Stage The  Company has established the existence of mineralized materials for  certain uranium projects, including the Lost Creek property The  Company has not established proven or probable reserves, as defined  by the United States Securities and Exchange Commission (the  “SEC”) under Industry Guide 7, through the completion  of a “final” or “bankable” feasibility  study for any of its uranium projects, including Lost Creek  property. Furthermore, the Company has no plans to establish proven  or probable reserves for any of its uranium projects for which the  Company plans on utilizing in-situ recovery (“ISR”)  mining, such as the Lost Creek property or the Shirley Basin mine.  As a result, and despite the fact that the Company commenced  extraction of U3O8 at the Lost Creek property  in September 2013, the Company remains in the Exploration Stage as  defined under Industry Guide 7, and will continue to remain in the  Exploration Stage until such time proven or probable reserves have  been established. Since  the Company commenced extraction of mineralized materials at the  Lost Creek property without having established proven and probable  reserves, any mineralized materials established or extracted from  the Lost Creek property should not be in any way associated with  having established or produced from proven or probable  reserves. In  accordance with U.S. GAAP, expenditures relating to the acquisition  of mineral rights are initially capitalized as incurred while  exploration and pre-extraction expenditures are expensed as  incurred until such time the Company exits the Exploration Stage by  establishing proven or probable reserves. Expenditures relating to  exploration activities such as drill programs to search for  additional mineralized materials are expensed as incurred.  Expenditures relating to activities such as the construction of  mine wellfields, header houses and disposal wells are expensed as  incurred until such time proven or probable reserves are  established for that uranium project, after which subsequent  expenditures relating to mine development activities for that  particular project are capitalized as incurred   Companies in the Production Stage as defined under Industry Guide  7, having established proven and probable reserves and exited the  Exploration Stage, typically capitalize expenditures relating to  ongoing development activities, with corresponding depletion  calculated over proven and probable reserves using the  units-of-production method and allocated to future reporting  periods to inventory and, as that inventory is sold, to cost of  goods sold. The Company is in the Exploration Stage which has  resulted in the Company reporting larger losses than if it had been  in the Production Stage due to the expensing, instead of  capitalizing, of expenditures relating to ongoing wellfield  development activities. Additionally, there would be no  corresponding amortization allocated to future reporting periods of  the Company since those costs would have been expensed previously,  resulting in both lower inventory costs and cost of goods sold and  results of operations with higher gross profits and lower losses  than if the Company had been in the Production Stage. Any  capitalized costs, such as expenditures relating to the acquisition  of mineral rights and asset retirement obligations, are amortized  over the estimated mineral life using the straight-line method. As  a result, the Company’s consolidated financial statements may  not be directly comparable to the financial statements of companies  in the Production Stage. | ||||||||||
| Development Stage Entity |   Development Stage Entity Prior  to the quarter ended December 31, 2013 (fiscal year ending December  31, 2013), the Company met the definition of a Development Stage  Entity as defined under Accounting Standards Codification Section  915: Development Stage Entities (“ASC 915”) and  presented the additional financial statement disclosures required  by a Development Stage Entity under ASC 915, including the  presentation of cumulative amounts since inception for the  consolidated statements of operations and comprehensive loss,  stockholders’ equity and cash flows. During the quarter ended  December 31, 2013, the Company generated significant revenue from  its planned principal operations by completing its first sale of  uranium concentrates.   The Company, therefore, no longer met the definition of a  Development Stage Entity. Accordingly, and starting with the filing  of its Form 10-K for the year ended December 31, 2013, the Company  no longer presented the additional financial statement disclosures  required by a Development Stage Entity under ASC 915 | ||||||||||
| Use of estimates |   Use of estimates
 The preparation of  consolidated financial statements in conformity with US GAAP  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 periods. The most significant estimates management  makes in the preparation of these consolidated financial statements  relate to potential impairment in the carrying value of the  Company’s long-lived assets, fair value of stock-based  compensation, valuation of the in-process inventory and estimation  of asset recovery obligations. Actual results could differ from  those estimates. | ||||||||||
| Cash and cash equivalents |   Cash and cash  equivalents
 Cash equivalents are  investments in guaranteed investment certificates, certificates of  deposit and money market accounts which have a term to maturity at  the time of purchase of 90 days or less and which are readily  convertible into cash. | ||||||||||
| Restricted cash |   Restricted cash
 Cash which is  restricted contractually or which secures various instruments  including surety bonds and letters of credit securing reclamation  obligations is shown as restricted cash | ||||||||||
| Inventory |   Inventory
 
  In-process inventory represents U3O8 that has  been extracted from the wellfield and captured in the processing  plant and is currently being transformed into a saleable  product.   Plant inventory is U3O8 that is contained in  yellowcake, which has been dried and packaged in drums, but not yet  shipped to the conversion facility.   The amount of U3O8 in the plant inventory is  determined by weighing and assaying the amount of  U3O8 packaged into drums at the plant.  Conversion facility inventory is  U3O8 that has been  shipped to the conversion facility.   The amount of U3O8  in the conversion facility inventory includes the amount of  U3O8 contained in drums shipped to the  conversion facility plus or minus any final weighing and assay  adjustments per the terms of the uranium supplier’s agreement  with the conversion facility. 
 The Company’s  inventories are measured at the lower of cost or net realizable  value and reflect the uranium content  (“U3O8”) in various stages of the  production and sales process including in-process inventory, plant  inventory and conversion facility inventory.    Operating supplies are expensed when purchased. | ||||||||||
| Mineral properties |   Mineral  properties
 Acquisition costs of  mineral properties are capitalized. When production is attained,  these costs are amortized over the estimated productive life of the  property. If properties are abandoned or sold, they are written  off. If properties are considered to be impaired in value, the  costs of the properties are written down to their estimated fair  value at that time. | ||||||||||
| Exploration, evaluation and development costs | Exploration,  evaluation and development costs   Exploration and evaluation expenses consist of labor, annual  exploration lease and maintenance fees and associated costs of the  exploration geology department as well as land holding and  exploration costs including drilling and analysis on properties  which have not reached the permitting or operations stage.  Development expense relates to the Company’s Lost Creek and  LC East projects, which are more advanced in terms of permitting  and development. 
  Development  expenditures for wellfields that are either in production or are  being prepared for production, including the cost of wells, pumps,  piping, and header houses, are expensed as incurred.
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| Construction in progress | Construction in  progress Construction in  progress consists of costs associated with the construction of the  Lost Creek facility.   It includes design, engineering, site preparation, plant  construction and related asset retirement obligation assets.   Once production commences construction in process is relieved.   Costs associated with the plant construction and related equipment  are capitalized and depreciated.      | ||||||||||
| Capital assets | Capital  assets 
  Property, plant and equipment assets, including machinery,  processing equipment, enclosures, vehicles and expenditures that  extend the life of such assets, are recorded at cost including  acquisition and installation costs. The costs of self-constructed  assets include direct construction costs, direct overhead and  allocated interest during the construction phase. Depreciation is  calculated using a declining  balance method for most assets with the  exception of the plant enclosure and related equipment.   Depreciation on the plant enclosure and related equipment is  calculated on a straight-line basis.   Estimated lives for depreciation purposes range from three years  for computer equipment and software to 20  years for the plant enclosure and equipment.
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| Equity investments | Equity  investments Investments in which  the Company has a significant influence are accounted for using the  equity method, whereby the Company records its proportionate share  of the investee’s income or loss. | ||||||||||
| Impairment of long-lived assets | Impairment of  long-lived assets The Company assesses  the possibility of impairment in the net carrying value of its  long-lived assets when events or circumstances indicate that the  carrying amounts of the asset or asset group may not be  recoverable. When potential impairment is indicated, management  calculates the estimated undiscounted future net cash flows  relating to the asset or asset group using estimated future prices,  recoverable resources, and operating, capital and reclamation  costs. When the carrying value of an asset exceeds the related  undiscounted cash flows, the asset is written down to its estimated  fair value, which is determined using discounted future cash flows  or other measures of fair value. | ||||||||||
| Asset retirement obligation | Asset retirement  obligations 
For  mining properties, various federal and state mining laws and  regulations require the Company to reclaim the surface areas and  restore underground water quality to the pre-existing quality or  class of use after the completion of mining. The  Company   records the fair value of an asset retirement obligation as a  liability in the period in which it incurs an obligation associated  with the retirement of tangible long-lived assets that result from  the acquisition, construction, development and/or normal use of the  assets. Asset retirement obligations consist of estimated final  well closures, plant closure and removal and associated ground  reclamation costs to be incurred by the Company in the future.   The estimated fair value of the asset retirement obligation is  based on the current cost escalated at an inflation rate and  discounted at a credit adjusted risk-free rate. This liability is  capitalized as part of the cost of the related asset and amortized  over its useful life. The liability accretes until the Company  settles the obligation.
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| Revenue recognition |   Revenue recognition The  recognition of revenue from the sale of U3O8  is in accordance with the guidelines outlined in ASC Section  605-10-25, Revenue Recognition. The Company delivers  U3O8 to a conversion facility and receives  credit for a specified quantity measured in pounds once the product  is confirmed to meet the required specifications. When a delivery  is approved, the Company notifies the conversion facility with  instructions for a title transfer to the customer. Revenue is  recognized once a title transfer of the U3O8  is confirmed by the conversion facility. As  discussed below, the Company sold two years of delivery commitments  to an independent broker.   The proceeds are recorded as deferred revenue until the broker or  purchaser acknowledges the deliveries have been made at which time,  the portion of the sale relating to those deliveries is taken into  sales revenue. | ||||||||||
| Stock-based compensation | Stock-based  compensation All stock-based  compensation payments made to employees, directors and consultants  are accounted for in the consolidated financial statements.  Stock-based compensation cost is measured at the grant date based  on the fair value of the reward and is recognized over the related  service period.   Stock-based compensation cost is charged to construction,  exploration and evaluation, development, and general and  administrative expense on the same basis as other compensation  costs. | ||||||||||
| Income taxes | Income  taxes The Company accounts  for income taxes under the asset and liability method which  requires the recognition of future income tax assets and  liabilities for the expected future tax consequences of temporary  differences between the carrying amounts and tax bases of assets  and liabilities.   The Company provides a valuation allowance on future tax assets  unless it is more likely than not that such assets will be  realized. | ||||||||||
| Loss per common share | Loss per common  share Basic loss per  common share is calculated based upon the weighted average number  of common shares outstanding during the period.   The diluted loss per common share, which is calculated using the  treasury stock method, is equal to the basic loss per common share  due to the anti-dilutive effect of stock options, restricted share  units and share purchase warrants outstanding. | ||||||||||
| Classification of financial instruments | Classification of  financial instruments The Company’s  financial instruments consist of cash and cash equivalents,  short-term investments, accounts receivable, restricted cash,  deposits, accounts payable and accrued liabilities, other  liabilities and notes payable.   The Company has made the following classifications for these  financial instruments: 
 
 
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| New accounting pronouncements | New accounting  pronouncements The Company  continues to monitor new accounting pronouncements and their  applicability to the Company’s operations and reporting.   During 2013, there were no new pronouncements which directly  affected the Company’s accounting policies or  reporting. |