Medical Oncology Partners (Details) - USD ($)		3 Months Ended
	Dec. 31, 2016	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 23, 2016
Medical Oncology Partners [Abstract]
Carrying value of investment		$ 164,000		$ 164,000
Condensed Consolidated Income Statement Information [Abstract]
Patient revenue		865,000	$ 984,000
USNC's equity in (loss) earnings		$ (30,000)	112,000
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
Condensed Consolidated Income Statement Information [Abstract]
Patient revenue		520,000	230,000
Net loss		(17,000)	(45,000)
USNC's equity in (loss) earnings	$ (12,000)	(6,000)	$ (16,000)
Condensed Consolidated Balance Sheet Information [Abstract]
Current assets		34,000		41,000
Noncurrent assets		143,000		108,000
Total assets		177,000		149,000
Current liabilities		738,000		693,000
Noncurrent liabilities		0		0
Deficit		(561,000)		(544,000)
Total liabilities and equity		177,000		$ 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%