Document and Entity Information - USD ($)	12 Months Ended
	Jun. 30, 2018	Aug. 20, 2018	Dec. 31, 2017
Document and Entity Information
Entity Registrant Name	IMMUNOMEDICS INC
Entity Central Index Key	0000722830
Current Fiscal Year End Date	--06-30
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2018
Trading Symbol	IMMU
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		186,832,011
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 2,606,095,987