Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity and Capital Stock - addl information (Details)

v2.4.1.9
Shareholders' Equity and Capital Stock - addl information (Details)
 0 Months Ended 1 Months Ended 12 Months Ended 12 Months Ended 12 Months Ended 1 Months Ended 12 Months Ended 12 Months Ended
Dec. 19, 2013
USD ($)
Feb. 23, 2012
USD ($)
Jan. 31, 2015
Dec. 31, 2014
USD ($)
Dec. 31, 2013
USD ($)
Dec. 31, 2012
USD ($)
Dec. 31, 2014
CAD
Dec. 31, 2013
CAD
Dec. 19, 2013
USD ($)
Dec. 31, 2012
CAD
Feb. 23, 2012
USD ($)
Dec. 31, 2011
USD ($)
Dec. 31, 2014
Capital Stock
Dec. 31, 2013
Capital Stock
Dec. 31, 2012
Capital Stock
Dec. 31, 2014
Warrants
Dec. 31, 2014
In Money Stock Option [Member]
USD ($)
Jan. 31, 2015
Restricted Stock Units (Rsus) [Member]
Dec. 31, 2014
Restricted Stock Units (Rsus) [Member]
USD ($)
Dec. 31, 2014
Restricted Stock Units (Rsus) [Member]
Capital Stock
Dec. 31, 2013
Employee Stock Option [Member]
USD ($)
Dec. 31, 2012
Employee Stock Option [Member]
USD ($)
Dec. 31, 2014
Four and One Half Months After Grant [Member]
Dec. 31, 2014
Nine Months After Grant [Member]
Dec. 31, 2014
Thirteen and One Half Months After Grant [Member]
Dec. 31, 2014
Eighteen Months After Date Of Grant [Member]
Dec. 31, 2014
First Anniversary [Member]
Dec. 31, 2014
Second Anniversary [Member]
Stockholder's Equity Note [Line Items]                                                        
Common Stock Shares Issued In Exchange Of Restricted Shares Units     215,168urg_CommonStockSharesIssuedInExchangeOfRestrictedSharesUnits 182,194urg_CommonStockSharesIssuedInExchangeOfRestrictedSharesUnits 338,451urg_CommonStockSharesIssuedInExchangeOfRestrictedSharesUnits 120,359urg_CommonStockSharesIssuedInExchangeOfRestrictedSharesUnits                                            
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period       1,623,139us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised 377,927us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised 88,473us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised             1,623,139us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember 		377,927us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember 		88,473us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember 		                         
Proceeds from Stock Options Exercised       $ 1,347,000us-gaap_ProceedsFromStockOptionsExercised $ 275,000us-gaap_ProceedsFromStockOptionsExercised $ 75,000us-gaap_ProceedsFromStockOptionsExercised                             $ 300,000us-gaap_ProceedsFromStockOptionsExercised
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember 		$ 100,000us-gaap_ProceedsFromStockOptionsExercised
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember 		           
Stock Issued During Period, Shares, New Issues 4,709,089us-gaap_StockIssuedDuringPeriodSharesNewIssues 17,250,000us-gaap_StockIssuedDuringPeriodSharesNewIssues                                                    
Share Price             0.99us-gaap_SharePrice   $ 1.10us-gaap_SharePrice   $ 1.00us-gaap_SharePrice                                  
Payments Of Stock Issuance Costs 200,000us-gaap_PaymentsOfStockIssuanceCosts 1,000,000us-gaap_PaymentsOfStockIssuanceCosts   50,000us-gaap_PaymentsOfStockIssuanceCosts 238,000us-gaap_PaymentsOfStockIssuanceCosts 1,003,000us-gaap_PaymentsOfStockIssuanceCosts                                            
Proceeds from Issuance of Private Placement 5,100,000us-gaap_ProceedsFromIssuanceOfPrivatePlacement                                                      
Stock Issued During Period, Value, New Issues   17,300,000us-gaap_StockIssuedDuringPeriodValueNewIssues                                                    
Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Percentage       10.00%urg_Share-BasedCompensationArrangementByShare-BasedPaymentAwardAwardVestingPercentage                                     22.00%urg_Share-BasedCompensationArrangementByShare-BasedPaymentAwardAwardVestingPercentage
/ urg_AwardVestingPeriodAxis
= urg_FourAndOne-HalfMonthsAfterGrantMember 		22.00%urg_Share-BasedCompensationArrangementByShare-BasedPaymentAwardAwardVestingPercentage
/ urg_AwardVestingPeriodAxis
= urg_NineMonthsAfterGrantMember 		22.00%urg_Share-BasedCompensationArrangementByShare-BasedPaymentAwardAwardVestingPercentage
/ urg_AwardVestingPeriodAxis
= urg_ThirteenAndOne-HalfMonthsAfterGrantMember 		24.00%urg_Share-BasedCompensationArrangementByShare-BasedPaymentAwardAwardVestingPercentage
/ urg_AwardVestingPeriodAxis
= urg_EighteenMonthsAfterTheDateOfGrantMember 		   
Share-Based Compensation Arrangement By Share-Based Payment Award, Options, Outstanding, Number       8,468,614us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber 9,273,659us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber 8,511,722us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber           6,413,902us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber         3,336,671us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= urg_InTheMoneyStockOptionMember 		                     
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number       7,023,022us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber                         3,336,671us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
/ us-gaap_AwardTypeAxis
= urg_InTheMoneyStockOptionMember 		                     
Stock based compensation       928,000us-gaap_ShareBasedCompensation 1,153,000us-gaap_ShareBasedCompensation 2,410,000us-gaap_ShareBasedCompensation                                            
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options                                 600,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
/ us-gaap_AwardTypeAxis
= urg_InTheMoneyStockOptionMember 		                     
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Share-based Awards Other than Options                                     300,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember 		                 
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition                                 1 year 1 month 6 days   1 year 7 months 6 days                  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value       $ 800,000us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1                                                
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period       259,192us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod 273,834us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod 703,572us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod                                            
RSUs vested but not redeemed (in shares)                                     280,529urg_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsVestedOutstandingNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember 		                 
RSUs redeemed against tax effect (in shares)                                   65,361urg_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsNumberRedeemedForTaxEffect
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember 		                   
Number of securities called by each unit                         1us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember 		    0.5us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_WarrantMember 		      1us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember 		               
Class Of Warrant Or Right Issued Number 2,354,545urg_ClassOfWarrantOrRightIssuedNumber                                                      
Class of Warrant or Right, Exercise Price of Warrants or Rights       $ 1.19us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1 $ 1.19us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1 $ 1.06us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1     $ 1.35us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1     $ 1.12us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1                                
Share-Based Compensation Arrangement By Share-Based Payment Award, Restricted Share Units Vesting Percentage                                                     50.00%urg_Share-BasedCompensationArrangementByShare-BasedPaymentAwardRestrictedShareUnitsVestingPercentage
/ urg_AwardVestingPeriodAxis
= urg_FirstAnniversaryMember 		50.00%urg_Share-BasedCompensationArrangementByShare-BasedPaymentAwardRestrictedShareUnitsVestingPercentage
/ urg_AwardVestingPeriodAxis
= urg_SecondAnniversaryMember
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price             0.96us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice 1.20us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice   0.82us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice