Annual report pursuant to Section 13 and 15(d)

Private Placement (Details 1)

v2.4.1.9
Private Placement (Details 1) (USD $)
6 Months Ended 12 Months Ended
Jun. 24, 2014
Dec. 31, 2013
Dec. 31, 2014
Private Placement [Line Items]      
Aggregate fair value   $ 6,277,000us-gaap_DerivativeLiabilitiesCurrent $ 0us-gaap_DerivativeLiabilitiesCurrent
Consulting Warrant [Member]      
Private Placement [Line Items]      
Stock price on valuation date $ 14.69us-gaap_SharePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
$ 1.68us-gaap_SharePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
 
Exercise price $ 0.04us-gaap_FairValueAssumptionsExercisePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
$ 0.04us-gaap_FairValueAssumptionsExercisePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
 
Term (years) 3 years 10 months 20 days 4 years 4 months 17 days  
Expected volatility 60.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
60.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
 
Dividend yield 0.00%us-gaap_FairValueAssumptionsExpectedDividendRate
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
0.00%us-gaap_FairValueAssumptionsExpectedDividendRate
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
 
Weighted average risk-free interest rate 1.33%us-gaap_FairValueAssumptionsRiskFreeInterestRate
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
1.75%us-gaap_FairValueAssumptionsRiskFreeInterestRate
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
 
Number of warrants 278,228watt_FairValueAssumptionsNumberOfWarrants
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
278,228watt_FairValueAssumptionsNumberOfWarrants
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
 
Number of trials 20,000watt_FairValueAssumptionNumberOfTrials
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
20,000watt_FairValueAssumptionNumberOfTrials
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
 
Aggregate fair value 4,019,000us-gaap_DerivativeLiabilitiesCurrent
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
529,000us-gaap_DerivativeLiabilitiesCurrent
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_ConsultingWarrantMember
 
Financing Warrant [Member]      
Private Placement [Line Items]      
Stock price on valuation date $ 14.69us-gaap_SharePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember
$ 1.68us-gaap_SharePrice
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember
 
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
Term (years) 3 years 10 months 20 days 4 years 4 months 17 days  
Expected volatility 60.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember
60.00%us-gaap_FairValueAssumptionsExpectedVolatilityRate
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember
 
Dividend yield 0.00%us-gaap_FairValueAssumptionsExpectedDividendRate
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember
0.00%us-gaap_FairValueAssumptionsExpectedDividendRate
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember
 
Weighted average risk-free interest rate 1.33%us-gaap_FairValueAssumptionsRiskFreeInterestRate
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember
1.75%us-gaap_FairValueAssumptionsRiskFreeInterestRate
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember
 
Number of warrants 152,778watt_FairValueAssumptionsNumberOfWarrants
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember
220,905watt_FairValueAssumptionsNumberOfWarrants
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember
 
Number of trials 20,000watt_FairValueAssumptionNumberOfTrials
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember
20,000watt_FairValueAssumptionNumberOfTrials
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember
 
Aggregate fair value $ 1,733,000us-gaap_DerivativeLiabilitiesCurrent
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember
$ 175,000us-gaap_DerivativeLiabilitiesCurrent
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= watt_FinancingWarrantMember