Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Jul. 16, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	ENERGY FOCUS, INC/DE
Entity Central Index Key	0000924168
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Current Reporting Status	Yes
Entity Shell Company	false
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		12,370,030