Quarterly report pursuant to Section 13 or 15(d)

Inventory (Narrative) (Details)

v2.4.1.9
Inventory (Narrative) (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Inventory [Line Items]      
Inventory reserves $ 659us-gaap_InventoryValuationReserves   $ 539us-gaap_InventoryValuationReserves
Production Materials      
Inventory [Line Items]      
Inventory reserves related to production issues 120us-gaap_InventoryWriteDown
/ us-gaap_PublicUtilitiesInventoryAxis
= navb_ProductionMember
   
In Process Research and Development      
Inventory [Line Items]      
Inventory reserves related to production issues $ 37us-gaap_InventoryWriteDown
/ us-gaap_PublicUtilitiesInventoryAxis
= us-gaap_InProcessResearchAndDevelopmentMember
$ 10us-gaap_InventoryWriteDown
/ us-gaap_PublicUtilitiesInventoryAxis
= us-gaap_InProcessResearchAndDevelopmentMember