Organization and Nature of Operations (Details Textual)	12 Months Ended
Dec. 31, 2014
Organization And Nature Of Operations [Line Items]
Number Of Products In Development	2

Represents of Organization And Nature Of Operations.

No definition available.

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