Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation (Details 6)

v2.4.1.9
Stock-Based Compensation (Details 6) (USD $)
In Thousands, except Share data, unless otherwise specified
12 Months Ended 0 Months Ended
Dec. 31, 2014
Mar. 31, 2014
Stock Options    
Stock-Based compensation    
Unrecognized compensation expense related to unvested stock options $ 3,329us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
/ us-gaap_AwardTypeAxis
= env_EmployeeAndOtherStockOptionMember
 
Unrecognized compensation expense related to unvested stock options and restricted stock, weighted-average recognition period 2 years 2 months 12 days  
Restricted stock with performance and subsequent service conditions    
Stock-Based compensation    
Unrecognized compensation expense related to unvested restricted 2,770us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
/ us-gaap_AwardTypeAxis
= env_RestrictedStockWithPerformanceConditionsAndSubsequentServiceConditionsMember
 
Unvested restricted stock, service condition 2 years  
Restricted stock with performance and subsequent service conditions | Minimum    
Stock-Based compensation    
Unrecognized compensation expense related to unvested stock options and restricted stock, weighted-average recognition period 3 months 18 days  
Restricted stock with performance and subsequent service conditions | Maximum    
Stock-Based compensation    
Unrecognized compensation expense related to unvested stock options and restricted stock, weighted-average recognition period 2 years 3 months 18 days  
Service-based vesting | Restricted Stock    
Stock-Based compensation    
Unrecognized compensation expense related to unvested stock options and restricted stock, weighted-average recognition period 2 years 2 months 12 days  
Unrecognized compensation expense related to unvested restricted $ 13,152us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ env_VestingCriteriaAxis
= env_VestingBasedOnServiceMember
 
First year performance condition achieved | Restricted Stock    
Stock-Based compensation    
Vested (in shares)   181,625env_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPerformanceVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ env_VestingCriteriaAxis
= env_FirstYearPerformanceConditionAchievedMember
Second year performance condition achieved | Restricted Stock    
Stock-Based compensation    
Vested (in shares)   290,544env_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPerformanceVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ env_VestingCriteriaAxis
= env_SecondYearPerformanceConditionAchievedMember