Medical Oncology Partners (Details) - USD ($)		3 Months Ended		9 Months Ended
	Dec. 31, 2016	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 23, 2016
Medical Oncology Partners [Abstract]
Carrying value of investment		$ 276,000		$ 276,000		$ 179,000
Condensed Consolidated Income Statement Information [Abstract]
Patient revenue		662,000	$ 658,000	2,005,000	$ 2,324,000
USNC's equity in loss		(56,000)	(135,000)	(292,000)	(799,000)
Condensed Balance Sheet Information [Abstract]
Current assets		2,699,000		2,699,000		2,681,000
Total assets		4,415,000		4,415,000		4,997,000
Current liabilities		790,000		790,000		1,638,000
Total liabilities and deficit		4,415,000		$ 4,415,000		4,997,000
Medical Oncology Partners LLC [Member]
Medical Oncology Partners [Abstract]
Equity interest percentage to be acquired by subsidiary				100.00%
Investments in unconsolidated entities				$ 450,000
Amount of capital contributed by company				36,000
Outstanding amount		1,362,000		1,362,000		1,126,000
Outstanding amount, less allowances		1,125,000		1,125,000		796,000
Due from related parties		237,000		237,000		330,000
Condensed Consolidated Income Statement Information [Abstract]
USNC's equity in loss	$ (12,000)
Medical Oncology Partners LLC [Member] | Other Investor [Member]
Medical Oncology Partners [Abstract]
Investments in unconsolidated entities				105,000
Medical Oncology Partners LLC [Member] | USNC [Member]
Medical Oncology Partners [Abstract]
Investments in unconsolidated entities				173,000
Ownership percentage							35.83%
Carrying value of investment		$ 149,000		149,000			$ 161,000
Medical Oncology Partners LLC [Member] | USNC [Member] | Dr. Jaime Lozano [Member]
Medical Oncology Partners [Abstract]
Investments in unconsolidated entities				$ 345,000
Ownership percentage		76.67%		76.67%
Percentage of equity interest to an additional investor as a consulting fee for services				5.00%
Medical Oncology Partners LLC [Member] | Investment in Unconsolidated Entity [Member]
Condensed Consolidated Income Statement Information [Abstract]
Patient revenue		$ 541,000	668,000	$ 1,473,000	2,015,000
Net loss		(345,000)	(102,000)	(1,041,000)	(205,000)
USNC's equity in loss		(124,000)	$ (36,000)	(373,000)	$ (73,000)
Condensed Balance Sheet Information [Abstract]
Current assets		180,000		180,000		247,000
Noncurrent assets		575,000		575,000		807,000
Total assets		755,000		755,000		1,054,000
Current liabilities		2,671,000		2,671,000		1,907,000
Noncurrent liabilities		305,000		305,000		427,000
Deficit		(2,221,000)		(2,221,000)		(1,280,000)
Total liabilities and deficit		$ 755,000		$ 755,000		$ 1,054,000