Represents value of authorized rights offering as per registration statement.

No definition available.

Name:	neph_AuthorizedValueOfRightsOffering
Namespace Prefix:	neph_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents gross proceeds from rights issued into shares.

+ References

No definition available.

+ Details

Name:	neph_ClassOfWarrantOrRightIssuedGrossValueReceived
Namespace Prefix:	neph_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents net proceeds from rights issued into shares.

+ References

No definition available.

+ Details

Name:	neph_ClassOfWarrantOrRightIssuedNetValueReceived
Namespace Prefix:	neph_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents number of rights issued into shares.

+ References

No definition available.

+ Details

Name:	neph_ClassOfWarrantOrRightIssuedShares
Namespace Prefix:	neph_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents reimbursement of legal fee.

+ References

No definition available.

+ Details

Name:	neph_ReimbursementOfLegalFee
Namespace Prefix:	neph_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents repayment of accrued interest on senior secured note.

+ References

No definition available.

+ Details

Name:	neph_RepaymentsOfAccruedInterestOnSeniorSecuredNote
Namespace Prefix:	neph_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	neph_StockholderEquityNoteLineItems
Namespace Prefix:	neph_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Subscription rights percentage.

+ References

No definition available.

+ Details

Name:	neph_SubscriptionRightsPercentage
Namespace Prefix:	neph_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 1A

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399

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=31042434&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.8)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 8

-Article 5

+ Details

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

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(i)(4))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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

- Definition

Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

+ References

No definition available.

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of the fee that accompanies borrowing money under the debt instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of expense provided in the period for legal costs incurred on or before the balance sheet date pertaining to resolved, pending or threatened litigation, including arbitration and mediation proceedings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.3)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

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

- Definition

The cash outflow for a long-term debt where the holder has highest claim on the entity's asset in case of bankruptcy or liquidation during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of new stock issued during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Stockholders' Deficit (Details Textual) (USD $)	1 Months Ended			0 Months Ended	1 Months Ended	12 Months Ended
Stockholders' Deficit (Details Textual) (USD $)	Dec. 18, 2014	Aug. 29, 2014	Mar. 21, 2014	Nov. 12, 2013	May 22, 2013	Dec. 31, 2014	Dec. 31, 2013	Nov. 10, 2014	Oct. 20, 2014	Feb. 14, 2014	Jan. 07, 2014	May 17, 2013	Mar. 04, 2013
Stockholder Equity Note [Line Items]
Authorized value of rights offering									$ 3,000,000neph_AuthorizedValueOfRightsOffering		$ 2,800,000neph_AuthorizedValueOfRightsOffering		$ 3,000,000neph_AuthorizedValueOfRightsOffering
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right								0.11901		0.28673		0.18776
Class of warrant or right issued, shares	5,000,000neph_ClassOfWarrantOrRightIssuedShares				5,000,000neph_ClassOfWarrantOrRightIssuedShares
Class of warrant or right issued gross value received	3,000,000		2,100,000		3,000,000
Class of warrant or right issued net value received	1,100,000		581,000		1,400,000
Repayments of accrued interest on senior secured note	64,000		61,000		46,800
Class of Warrant or Right, Exercise Price of Warrants or Rights						$ 0.33	$ 0.45	$ 0.60		$ 0.30		$ 0.60
Debt Instrument, Fee Amount					104,000us-gaap_DebtInstrumentFeeAmount
Reimbursement of legal fee	75,000neph_ReimbursementOfLegalFee				100,000neph_ReimbursementOfLegalFee
Amortization of debt discount (premium)		177,000		195,000	204,000	320,000	257,000
Repayments of Senior Debt	1,750,000us-gaap_RepaymentsOfSeniorDebt		1,500,000us-gaap_RepaymentsOfSeniorDebt		1,300,000us-gaap_RepaymentsOfSeniorDebt	3,250,000us-gaap_RepaymentsOfSeniorDebt	1,300,000us-gaap_RepaymentsOfSeniorDebt
Subscription rights percentage			77.00%neph_SubscriptionRightsPercentage
Common stock of subscription rights			7,140,823			36,570
Legal fees			$ 128,000us-gaap_LegalFees