Energous Corporation Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail)

Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities	7,324,400	6,975,651	4,994,425
Consulting Warrant to Purchase Common Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities			146,252
Financing Warrant to Purchase Common Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities	13,889	13,889	152,778
IPO Warrants to Purchase Common Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities	11,600	11,600	460,000
IR Consulting Warrant [Member]
Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities		23,250	36,000
IR Incentive Warrant [Member]
Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities		15,000	15,000
Warrants Issued to Private Investors [Member]
Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities	3,035,688	2,381,675
Employee Stock Option [Member]
Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities	1,037,239	1,309,444	1,487,785
Restricted Stock Units (RSUs) [Member]
Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities	2,274,327	2,052,223	1,560,996
Performance Share Units [Member]
Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities	951,657	1,153,617	1,135,614
Deferred Stock Units [Member]
Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities		14,953