Investments in Unconsolidated Entities, Medical Oncology Partners (Details) - USD ($)		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 23, 2016
Medical Oncology Partners [Abstract]
Investments in unconsolidated entities		$ 141,000	$ 160,000
Advances to unconsolidated entities		491,000	459,000
Condensed Income Statement Information [Abstract]
Patient revenue		1,061,000	3,173,000
Net loss		(674,000)	533,000
USNC's equity in (loss) income		(470,000)	(809,000)
Condensed Balance Sheet Information [Abstract]
Current assets		2,243,000	3,007,000
Total assets		3,688,000	4,173,000
Current liabilities		327,000	410,000
Deficit		3,327,000	3,686,000	$ 3,153,000
Total liabilities and deficit		$ 3,688,000	4,173,000
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
Investments in unconsolidated entities		0
Amount of capital contributed by company			125,000
Advances to unconsolidated entities		461,000
Condensed Income Statement Information [Abstract]
USNC's equity in (loss) income	$ (12,000)		(686,000)
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%
Investments in unconsolidated entities		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
Percentage of equity interest to an additional investor as a consulting fee for services		5.00%
Ownership percentage		76.67%
Medical Oncology Partners LLC [Member] | Investment in Unconsolidated Entity [Member]
Condensed Income Statement Information [Abstract]
Patient revenue		$ 2,417,000	2,104,000
Net loss		(646,000)	(1,256,000)
USNC's equity in (loss) income		(231,000)	(450,000)
Condensed Balance Sheet Information [Abstract]
Current assets		201,000	204,000
Noncurrent assets		384,000	701,000
Total assets		585,000	905,000
Current liabilities		3,109,000	2,736,000
Noncurrent liabilities		92,000	410,000
Deficit		(2,616,000)	(2,241,000)
Total liabilities and deficit		$ 585,000	$ 905,000