Investment in Unconsolidated Entities, Medical Oncology Partners (Details) - USD ($)		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 23, 2016
Medical Oncology Partners [Abstract]
Carrying value of investment		$ 168,000	$ 164,000
Condensed Income Statement Information [Abstract]
Patient revenue		3,424,000	3,414,000
USNC's equity in (loss) earnings		$ (743,000)	(101,000)
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
Allowances for advances to unconsolidated entities		245,000	223,000
Condensed Income Statement Information [Abstract]
Patient revenue		2,257,000	1,298,000
Net loss		(282,000)	(272,000)
USNC's equity in (loss) earnings	$ (12,000)	(101,000)	(97,000)
Condensed Balance Sheet Information [Abstract]
Current assets		41,000	41,000
Noncurrent assets		159,000	108,000
Total assets		200,000	149,000
Current liabilities		1,002,000	693,000
Noncurrent liabilities		33,000	0
Deficit		(835,000)	(544,000)
Total liabilities and equity (deficit)		200,000	$ 149,000
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		$ 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%
Percentage of equity interest to an additional investor as a consulting fee for services		5.00%