Annual report pursuant to Section 13 and 15(d)

Private Placement (Details Textual)

v2.4.1.9
Private Placement (Details Textual) (USD $)
 12 Months Ended 1 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Apr. 30, 2014
Jun. 24, 2014
Aug. 16, 2014
Apr. 02, 2014
May 16, 2013
Private Placement [Line Items]              
Securities Purchase Agreement Initiation Date May 16, 2013            
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 3,261,360us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount 3,525,904us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount          
Amortization of Debt Discount (Premium) $ 964,851us-gaap_AmortizationOfDebtDiscountPremium $ 705,289us-gaap_AmortizationOfDebtDiscountPremium          
Fair Value Adjustment of Warrants 0us-gaap_FairValueAdjustmentOfWarrants 724,000us-gaap_FairValueAdjustmentOfWarrants          
Debt Conversion, Converted Instrument, Amount 26,790,177us-gaap_DebtConversionConvertedInstrumentAmount1 0us-gaap_DebtConversionConvertedInstrumentAmount1          
Debt Conversion, Converted Instrument, Shares Issued 1,833,336us-gaap_DebtConversionConvertedInstrumentSharesIssued1 96,792us-gaap_DebtConversionConvertedInstrumentSharesIssued1          
Debt Instrument, Convertible, Beneficial Conversion Feature 21,217,177us-gaap_DebtInstrumentConvertibleBeneficialConversionFeature 197,000us-gaap_DebtInstrumentConvertibleBeneficialConversionFeature          
Gains (Losses) on Extinguishment of Debt 2,084,368us-gaap_GainsLossesOnExtinguishmentOfDebt 0us-gaap_GainsLossesOnExtinguishmentOfDebt          
Stock Issued During Period, Value, Conversion of Convertible Securities 26,790,177us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities            
Adjustments to Additional Paid in Capital, Other 5,752,000us-gaap_AdjustmentsToAdditionalPaidInCapitalOther 0us-gaap_AdjustmentsToAdditionalPaidInCapitalOther          
Common Stock [Member]              
Private Placement [Line Items]              
Stock Issued During Period, Shares, Conversion of Convertible Securities 1,930,128us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember 		           
Stock Issued During Period, Value, Conversion of Convertible Securities 19us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember 		           
Adjustments to Additional Paid in Capital, Other 0us-gaap_AdjustmentsToAdditionalPaidInCapitalOther
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember 		           
Financing Warrant [Member]              
Private Placement [Line Items]              
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 152,778us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember 		220,905us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember 		         
Payments for Fees 538,393us-gaap_PaymentsForFees
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember 		           
Sale Of Warrants In Cash 1,000watt_SaleOfWarrantsInCash
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember 		           
Warrants Aggregate Exercise Price 550,000watt_WarrantsAggregateExercisePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember 		           
Percentage Exercise Price Of Warrants Determined Based On Conversion Price Of Convertible Notes 120.00%watt_PercentageExercisePriceOfWarrantsDeterminedBasedOnConversionPriceOfConvertibleNotes
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember 		           
Investment Warrants, Exercise Price $ 3.60invest_InvestmentWarrantsExercisePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember 		           
Percentage Of Warrants Exercise Based On Convertible Notes Conversion Price 120.00%watt_PercentageOfWarrantsExerciseBasedOnConvertibleNotesConversionPrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember 		           
Fair Value Adjustment of Warrants 186,500us-gaap_FairValueAdjustmentOfWarrants
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember 		           
Fair Value Assumptions, Exercise Price $ 3.60us-gaap_FairValueAssumptionsExercisePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember 		$ 2.49us-gaap_FairValueAssumptionsExercisePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember 		  $ 3.60us-gaap_FairValueAssumptionsExercisePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember 		     
Consulting Warrant [Member]              
Private Placement [Line Items]              
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 278,228us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember 		278,228us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember 		         
Sale Of Warrants In Cash 1,500watt_SaleOfWarrantsInCash
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember 		           
Investment Warrants, Exercise Price $ 0.04invest_InvestmentWarrantsExercisePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember 		           
Warrants Issued To Purchase Common Stock, Shares 278,228watt_WarrantsIssuedToPurchaseCommonStockShares
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember 		           
Fair Value Adjustment of Warrants 537,500us-gaap_FairValueAdjustmentOfWarrants
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember 		           
Fair Value Assumptions, Exercise Price   $ 0.04us-gaap_FairValueAssumptionsExercisePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember 		  $ 0.04us-gaap_FairValueAssumptionsExercisePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember 		     
Financing And Consulting Warrant [Member]              
Private Placement [Line Items]              
Increase (Decrease) in Derivative Liabilities 5,048,000us-gaap_IncreaseDecreaseInDerivativeLiabilities
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingAndConsultingWarrantMember 		20,000us-gaap_IncreaseDecreaseInDerivativeLiabilities
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingAndConsultingWarrantMember 		         
InterestPayable [Member]              
Private Placement [Line Items]              
Debt Conversion, Converted Instrument, Amount     290,219us-gaap_DebtConversionConvertedInstrumentAmount1
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_InterestpayableMember 		       
Debt Conversion, Converted Instrument, Shares Issued     96,792us-gaap_DebtConversionConvertedInstrumentSharesIssued1
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_InterestpayableMember 		       
Convertible Notes Payable [Member]              
Private Placement [Line Items]              
Debt Instrument, Face Amount             5,500,009us-gaap_DebtInstrumentFaceAmount
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleNotesPayableMember
Debt Instrument, Interest Rate, Stated Percentage         6.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleNotesPayableMember 		   
Debt Instrument, Maturity Date Aug. 16, 2014            
Debt Instrument, Convertible, Conversion Price $ 3.00us-gaap_DebtInstrumentConvertibleConversionPrice1
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleNotesPayableMember 		        $ 3.00us-gaap_DebtInstrumentConvertibleConversionPrice1
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleNotesPayableMember 		 
Debt Conversion, Converted Instrument, Amount     $ 5,500,009us-gaap_DebtConversionConvertedInstrumentAmount1
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleNotesPayableMember 		       
Debt Conversion, Converted Instrument, Shares Issued     1,833,336us-gaap_DebtConversionConvertedInstrumentSharesIssued1
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConvertibleNotesPayableMember