Annual report pursuant to Section 13 and 15(d)

Stock Based Compensation (Details Textual)

v2.4.1.9
Stock Based Compensation (Details Textual) (USD $)
 12 Months Ended 1 Months Ended 3 Months Ended 1 Months Ended 12 Months Ended
Dec. 31, 2014
Dec. 31, 2014
Nov. 30, 2014
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Aug. 31, 2014
Jul. 31, 2014
Dec. 31, 2013
Dec. 24, 2014
Nov. 13, 2014
Aug. 14, 2014
Mar. 15, 2014
Jul. 14, 2014
Mar. 26, 2014
Dec. 12, 2013
Mar. 06, 2014
Jan. 07, 2014
Feb. 27, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 1,542,477us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross                                      
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price $ 4.63us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice                                      
Restricted Stock Units (RSUs) [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition 3 years 5 months 19 days                                      
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period 837,672us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_RestrictedStockUnitsRSUMember 		                                     
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (6,349)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_RestrictedStockUnitsRSUMember 		                                     
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options $ 6,734,336us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_RestrictedStockUnitsRSUMember 		6,734,336us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_RestrictedStockUnitsRSUMember 		  6,734,336us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_RestrictedStockUnitsRSUMember 		                               
Employees And Consultants [Member] | Restricted Stock Units (RSUs) [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period   77,856us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= watt_EmployeesAndConsultantsMember 		261,686us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
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= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= watt_EmployeesAndConsultantsMember 		                                 
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding                     620,512us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= watt_EmployeesAndConsultantsMember 		2,266,201us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding
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= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= watt_EmployeesAndConsultantsMember 		               
Two New Independent Directors [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage       25.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_TitleOfIndividualAxis
= watt_TwoNewIndependentDirectorsMember 		25.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_TitleOfIndividualAxis
= watt_TwoNewIndependentDirectorsMember 		25.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_TitleOfIndividualAxis
= watt_TwoNewIndependentDirectorsMember 		25.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_TitleOfIndividualAxis
= watt_TwoNewIndependentDirectorsMember 		                         
Mr. Cesar Johnston | Restricted Stock Units (RSUs) [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period               100,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= us-gaap_VicePresidentMember 		                       
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding                         1,356,000us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_TitleOfIndividualAxis
= us-gaap_VicePresidentMember 		             
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period               4 years                        
Equity Incentive Plan 2013 [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized                   1,042,167us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member 		                   
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 80,201us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
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= watt_EquityIncentivePlan2013Member 		                                     
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price $ 4.99us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member 		                                     
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights vests 25% of the award on the anniversary of the employees date of hire and then will vest 1/48th of the initial award monthly during the following 36 months                                      
Share Based Compensation Arrangement by Share Based Payment Award, Options, Grant in Period, Weighted Average Grant Date Fair Value                           229,365watt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member 		           
Share-based Compensation Arrangement by Share-based Payment Award, Other Share Increase (Decrease) 2,335,967us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherShareIncreaseDecrease
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member 		                                     
Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Description and Terms 18%                                      
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period 10 years                                      
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures 531,661us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member 		                                     
Equity Incentive Plan 2013 [Member] | Restricted Stock Units (RSUs) [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period     5,100us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member 		          228,500us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
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= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member 		                     
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding                       44,166us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member 		981,100us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member 		             
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Date                 Mar. 28, 2018                      
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period               4 years 4 years                      
Equity Incentive Plan 2013 [Member] | Employees And Consultants [Member] | Restricted Stock Units (RSUs) [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period               86,823us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
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/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member
/ us-gaap_TitleOfIndividualAxis
= watt_EmployeesAndConsultantsMember 		                       
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding                             3,023,055us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding
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/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member
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= watt_EmployeesAndConsultantsMember 		         
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage 25.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
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= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member
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= watt_EmployeesAndConsultantsMember 		                                     
Equity Incentive Plan 2013 [Member] | Mr.Michael Leabman [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 251,474us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
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= watt_EquityIncentivePlan2013Member
/ us-gaap_TitleOfIndividualAxis
= watt_ChiefTechnicalOfficerMember 		                                     
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price $ 6.00us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member
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= watt_ChiefTechnicalOfficerMember 		                                     
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights vests 6/48th of the award on the grant date and 1/48th of the award on the last day of each of the subsequent 42 months                                      
Share Based Compensation Arrangement by Share Based Payment Award, Options, Grant in Period, Weighted Average Grant Date Fair Value                               844,643watt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantInPeriodWeightedAverageGrantDateFairValue
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= watt_EquityIncentivePlan2013Member
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= watt_ChiefTechnicalOfficerMember 		       
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period 10 years                                      
Equity Incentive Plan 2013 [Member] | Mr. George Holmes [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 89,672us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member
/ us-gaap_TitleOfIndividualAxis
= watt_VicePresidentOfSalesAndMarketingMember 		                                     
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price $ 6.00us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
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= watt_EquityIncentivePlan2013Member
/ us-gaap_TitleOfIndividualAxis
= watt_VicePresidentOfSalesAndMarketingMember 		                                     
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period 10 years                                      
Equity Incentive Plan 2013 [Member] | Mr. George Holmes [Member] | Restricted Stock Units (RSUs) [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period                 44,836us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
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= watt_EquityIncentivePlan2013Member
/ us-gaap_TitleOfIndividualAxis
= watt_VicePresidentOfSalesAndMarketingMember 		                     
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding                             593,180us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding
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/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member
/ us-gaap_TitleOfIndividualAxis
= watt_VicePresidentOfSalesAndMarketingMember 		         
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage 25.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
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/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member
/ us-gaap_TitleOfIndividualAxis
= watt_VicePresidentOfSalesAndMarketingMember 		                                     
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period 4 years                                      
Equity Incentive Plan 2013 [Member] | Mr. Rizzone [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 496,546us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember 		                275,689us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember 		                   
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price $ 6.00us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember 		                $ 1.68us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
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= watt_EquityIncentivePlan2013Member
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember 		                   
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights vests 6/48 of the award on the grant date and 1/48 of the award on the last day of each of the subsequent 42 months                 vests 1/48 for each completed month of service and for purposes of vesting only, the first completed month                    
Share Based Compensation Arrangement by Share Based Payment Award, Options, Grant in Period, Weighted Average Grant Date Fair Value                               1,667,784watt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantInPeriodWeightedAverageGrantDateFairValue
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= watt_EquityIncentivePlan2013Member
/ us-gaap_TitleOfIndividualAxis
= us-gaap_ChiefExecutiveOfficerMember 		258,373watt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantInPeriodWeightedAverageGrantDateFairValue
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= watt_EquityIncentivePlan2013Member
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= us-gaap_ChiefExecutiveOfficerMember 		     
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period 10 years                 10 years                    
Equity Incentive Plan 2013 [Member] | Consultant [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights vested 25% of the award on September 30, 2014 and continues to vest 1/48th of the award on the last day of each of the subsequent 36 months                                      
Share Based Compensation Arrangement by Share Based Payment Award, Options, Grant in Period, Weighted Average Grant Date Fair Value                               303,869watt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantInPeriodWeightedAverageGrantDateFairValue
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= watt_EquityIncentivePlan2013Member
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= watt_ConsultantMember 		       
Equity Incentive Plan 2013 [Member] | Consultant [Member] | Restricted Stock Units (RSUs) [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period   5,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
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= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_AwardTypeAxis
= watt_EquityIncentivePlan2013Member
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= watt_ConsultantMember 		                                   
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding                     39,850us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding
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= watt_EquityIncentivePlan2013Member
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= watt_ConsultantMember 		                 
Non-Employee Equity Compensation Plan 2014 [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized                                   250,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
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= watt_NonemployeeEquityCompensationPlan2014Member 		   
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage       25.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_AwardTypeAxis
= watt_NonemployeeEquityCompensationPlan2014Member 		25.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
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Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures 211,184us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
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Non-Employee Equity Compensation Plan 2014 [Member] | Restricted Stock Units (RSUs) [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Terms of Award vests 504 shares on each of the next five succeeding three month anniversaries of the grant date                                      
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period 4,035us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
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Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding 49,590us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding
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Non-Employee Equity Compensation Plan 2014 [Member] | Two New Independent Directors [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
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Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price $ 5.45us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
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Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights vest 25% on March 31, 2014, June 30, 2014, September 30, 2014 and December 31, 2014                                      
Share Based Compensation Arrangement by Share Based Payment Award, Options, Grant in Period, Weighted Average Grant Date Fair Value                           100,000watt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantInPeriodWeightedAverageGrantDateFairValue
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Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period 10 years                                      
Stock Plan 2013 [Member] | Employees And Consultants [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 537,845us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
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Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price $ 2.49us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
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Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period 10 years                                      
Stock Plan 2013 [Member] | Mr.Michael Leabman [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 57,644us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
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Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights 3/48ths on the date of grant, and will vest 1/48th monthly over the following 45 months                                      
Stock Plan 2013 [Member] | Mr. George Holmes [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 80,201us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
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Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights vested 25% on October 1, 2014 and then continues to vest 1/48th of the initial award monthly for the subsequent 36 months                                      
Stock Plan 2013 [Member] | Other Employees And Consultants [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 319,799us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
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Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights vest 25% of the award on the later of the first anniversary of the date they started working for the Company or October 1, 2014 and then will vest 1/48thof the initial award monthly for the following 36 months                                      
Share Based Compensation Arrangement by Share Based Payment Award, Options, Grant in Period, Weighted Average Grant Date Fair Value                                     762,699watt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantInPeriodWeightedAverageGrantDateFairValue
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Stock Plan 2013 [Member] | Two New Independent Directors [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
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Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price $ 3.63us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
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Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights vest 25% on March 31, 2014, June 30, 2014, September 30, 2014 and December 31, 2014                                      
Share Based Compensation Arrangement by Share Based Payment Award, Options, Grant in Period, Weighted Average Grant Date Fair Value                                       100,000watt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantInPeriodWeightedAverageGrantDateFairValue
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Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period 10 years                                      
Employee Stock Option [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options $ 2,611,490us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
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Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition 2 years 8 months 5 days                                      
Performance Shares [Member] | Mr. Cesar Johnston | Restricted Stock Units (RSUs) [Member]                                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                        
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period               20,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
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