Investment in Unconsolidated Entities, CB Oncology Partners (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
CB Oncology Partners [Abstract]
Advances to unconsolidated entities	$ 1,557,000	$ 593,000
Condensed Income Statement Information [Abstract]
Patient revenue	3,424,000	3,414,000
USNC's equity in (loss) earnings	$ (743,000)	(101,000)
CB Oncology Partners LLC Member [Member]
CB Oncology Partners [Abstract]
Ownership percentage	24.00%
Advances to unconsolidated entities	$ 1,258,000	143,000
Allowances for advances to unconsolidated entities	503,000
Carrying value of advances	898,000
Condensed Income Statement Information [Abstract]
Patient revenue	956,000	0
Net loss	(1,230,000)	(248,000)
USNC's equity in (loss) earnings	(298,000)	(60,000)
Condensed Balance Sheet Information [Abstract]
Current assets	140,000	0
Noncurrent assets	0	0
Total assets	140,000	0
Current liabilities	1,618,000	248,000
Noncurrent liabilities	0	0
Deficit	(1,478,000)	(248,000)
Total liabilities and equity (deficit)	$ 140,000	$ 0