CONSOLIDATED BALANCE SHEETS - USD ($)	Jun. 30, 2018	Jun. 30, 2017
Assets, Current [Abstract]
Cash and cash equivalents	$ 612,056,502	$ 43,393,570
Marketable securities	26,745,252	111,508,225
Accounts receivable, net of allowances of $0 and $9,371 at June 30, 2018, and 2017, respectively	45,773	488,723
Inventory	0	580,016
Prepaid expenses	3,802,583	891,284
Other current assets	5,729,710	436,344
Total current assets	648,379,820	157,298,162
Property and equipment, net of accumulated depreciation of $30,858,228 and $29,560,955 at June 30, 2018 and 2017, respectively	15,733,429	5,245,230
Other long-term assets	60,000	30,000
Total Assets	664,173,249	162,573,392
Liabilities, Current [Abstract]
Accounts payable and accrued expenses	31,663,648	31,366,976
Liability related to sale of future royalties - current	3,009,000	0
Warrant liabilities	8,973,214	90,706,206
Deferred revenues	93,669	170,967
Total current liabilities	43,739,531	122,244,149
Convertible Debt, Noncurrent	19,762,808	98,084,219
Liability related to sale of future royalties - non-current	198,997,995	0
Other long-term liabilities	1,987,249	1,708,272
Total Liabilities	264,487,583	222,036,640
Commitments and Contingencies (Note 15)	0	0
Stockholders’ Equity (Deficit):
Convertible preferred stock, $0.1 par value; authorized 10,000,000 shares; no shares issued and outstanding at June 30, 2018 and 1,000,000 shares issued and outstanding at June 30, 2017	0	10,000
Common stock, $0.1 par value; authorized 250,000,000 shares issued 186,801,159 shares and outstanding 186,766,434 shares at June 30, 2018; shares issued 110,344,643 shares and outstanding 110,309,918 shares at June 30, 2017	1,868,011	1,103,446
Capital contributed in excess of par	1,194,997,773	462,666,366
Treasury stock, at cost: 34,725 shares at June 30, 2018 and 2017	(458,370)	(458,370)
Accumulated deficit	(795,547,786)	(521,710,899)
Accumulated other comprehensive loss	(352,798)	(302,710)
Total Immunomedics, Inc. stockholders' equity (deficit)	400,506,830	(58,692,167)
Noncontrolling interest in subsidiary	(821,164)	(771,081)
Total stockholder's equity (deficit)	399,685,666	(59,463,248)
Total Liabilities and Stockholders' Equity	$ 664,173,249	$ 162,573,392