Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Jun. 14, 2019	Jun. 30, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	DELCATH SYSTEMS, INC.
Entity Central Index Key	0000872912
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 2,591,399
Entity Common Stock, Shares Outstanding		18,277,807
Document Fiscal Year Focus	2018
Trading Symbol	DCTH
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018