Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity Narrative (Details)

v2.4.1.9
Shareholders' Equity Narrative (Details) (USD $)
3 Months Ended 12 Months Ended 0 Months Ended
Feb. 01, 2014
Jan. 31, 2015
Feb. 01, 2014
Feb. 02, 2013
Oct. 03, 2012
Nov. 18, 2014
Mar. 13, 2014
Nov. 26, 2013
Jun. 19, 2013
Feb. 25, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Common stock, shares authorized 100,000,000us-gaap_CommonStockSharesAuthorized 100,000,000us-gaap_CommonStockSharesAuthorized 100,000,000us-gaap_CommonStockSharesAuthorized              
Common stock, shares issued 49,844,253us-gaap_CommonStockSharesIssued 56,448,663us-gaap_CommonStockSharesIssued 49,844,253us-gaap_CommonStockSharesIssued              
Debt Conversion, Converted Instrument, Warrants or Options Issued   5,058,741us-gaap_DebtConversionConvertedInstrumentWarrantsOrOptionsIssued1                
Class of Warrant or Right, Outstanding 6,000,000us-gaap_ClassOfWarrantOrRightOutstanding   6,000,000us-gaap_ClassOfWarrantOrRightOutstanding              
Allocated Share-based Compensation Expense   $ 2,537,000us-gaap_AllocatedShareBasedCompensationExpense $ 2,405,000us-gaap_AllocatedShareBasedCompensationExpense $ 1,682,000us-gaap_AllocatedShareBasedCompensationExpense            
Number of Omnibus Stock Plans   1evlv_NumberOfOmnibusStockPlans                
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period   3 years                
Granted, weighted average grant date fair value $ 3.96us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue $ 3.92us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue   $ 1.03us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue            
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value 469,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue 6,099,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue   146,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue            
Unrecognized compensation cost related to non-vested awards   1,633,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized                
Period for recognition of unrecognized compensation cost   1 year 11 months 26 days                
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options   1,129,000us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions 174,000us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions 52,000us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions            
Minimum [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Purchase price of common stock, percent   100.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
               
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period   10 years                
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period   3 years                
2011 Omnibus Incentive Plan [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Number of shares authorized   6,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ us-gaap_PlanNameAxis
= evlv_A2011OmnibusIncentivePlanMember
               
Granted, weighted average grant date fair value   $ 4.65us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_PlanNameAxis
= evlv_A2011OmnibusIncentivePlanMember
               
Market Based Stock Options Awards [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Granted, weighted average grant date fair value         $ 4.00us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_PlanNameAxis
= evlv_MarketBasedStockOptionsAwardsMember
         
2004 Omnibus Incentive Stock Plan [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Granted, weighted average grant date fair value   $ 5.66us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_PlanNameAxis
= evlv_A2004OmnibusIncentiveStockPlanMember
               
GE [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Class of Warrant or Right, Outstanding   0us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= evlv_GeMember
               
Class of Warrant or Right, Exercise Price of Warrants or Rights                   $ 0.75us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= evlv_GeMember
Restricted Stock [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period           3 years 3 years 3 years 12 months  
Granted, weighted average grant date fair value           $ 4.91us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
       
Unrecognized compensation cost related to non-vested awards   $ 2,616,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
               
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term   2 years 0 months 25 days