XML 55 R43.htm IDEA: XBRL DOCUMENT v3.8.0.1

Fair Value Measurements (Details Narrative) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended
	Mar. 31, 2017	Dec. 21, 2016	Mar. 31, 2018	Mar. 31, 2017
Warrant liability			$ (270)	$ (340)
Stock price			$ 1.47
Warrant [Member]
Warrant liability	$ 1,030	$ 1,030	$ 930
Term expiration date	Jun. 21, 2022	Jun. 21, 2022	Jun. 21, 2022
Exercise price	$ 2.05	$ 2.05	$ 1.13	$ 2.05
Stock price	$ 1.28	$ 1.28	$ 1.23	$ 1.28
Volatility rate	90.00%	90.00%	95.00%
Risk-free interest rate	2.01%	2.01%	2.50%
Warrants exercise price reduced			$ 0.392

X

- Definition

Refers to the date.

+ References

No definition available.

+ Details

Name:	USEG_FairValueAssumptionsExpectedDate
Namespace Prefix:	USEG_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Warrants exercise price reduced.

+ References

No definition available.

+ Details

Name:	USEG_WarrantsExercisePriceReduced
Namespace Prefix:	USEG_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of expense (income) related to adjustment to fair value of warrant liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section 25
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=6939902&loc=d3e20148-110875

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

Name:	us-gaap_FairValueAdjustmentOfWarrants
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Agreed upon price for the exchange of the underlying asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueAssumptionsExercisePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Risk-free interest rate assumption used in valuing an instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueAssumptionsRiskFreeInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Weighted average expected volatility of stock price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueAssumptionsWeightedAverageVolatilityRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_WarrantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: