Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84164817&loc=d3e45280-112737

The Southern California Regional Gamma Knife Center (Details)		1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 01, 2016 USD ($)	Feb. 29, 2016 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) Payment	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
The Southern California Regional Gamma Knife Center [Abstract]
Renovation installation and operation agreement period					14 years
Due from related parties			$ 0		$ 0		$ 1,141,000
Condensed Income Statement Information [Abstract]
Patient revenue			825,000	$ 1,121,000	1,666,000	$ 1,986,000
USNC's equity in earnings			(513,000)	(160,000)	(746,000)	(190,000)
Neuro Partners LLC and CGK [Member]
The Southern California Regional Gamma Knife Center [Abstract]
USNC's equity in earnings not recorded due to prior losses incurred						65,000
Recorded amount of equity method income					45,000		0
Condensed Income Statement Information [Abstract]
Patient revenue			189,000	299,000	489,000	510,000
Net income			22,000	170,000	147,000	227,000
USNC's equity in earnings			1,000	$ 52,000	45,000	$ 65,000
Condensed Balance Sheet Information [Abstract]
Current assets			418,000		418,000		304,000
Noncurrent assets			936,000		936,000		1,064,000
Total assets			1,354,000		1,354,000		1,368,000
Current liabilities			399,000		399,000		399,000
Noncurrent liabilities			763,000		763,000		924,000
Equity			192,000		192,000		45,000
Total liabilities and equity (deficit)			$ 1,354,000		$ 1,354,000		$ 1,368,000
Neuro Partners LLC [Member]
The Southern California Regional Gamma Knife Center [Abstract]
Ownership percentage			20.00%		20.00%
Neuro Partners LLC [Member] \| Lease One [Member]
The Southern California Regional Gamma Knife Center [Abstract]
Share of guarantee in lease obligations					20.00%
Lease term					7 years
Neuro Partners LLC [Member] \| Lease Two [Member]
The Southern California Regional Gamma Knife Center [Abstract]
Lease term					5 years
Number of lease payments \| Payment					60
Capital lease obligation		$ 1,663,000
Prior year lease obligations		$ 668,000
Capital lease payment	$ 31,000
CGK [Member]
The Southern California Regional Gamma Knife Center [Abstract]
Ownership percentage			39.00%		39.00%
Due from related parties			$ 8,000		$ 8,000