Annual report pursuant to Section 13 and 15(d)

Inventory (Details)

v2.4.1.9
Inventory (Details) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Inventory Disclosure [Abstract]      
Obsolescence reserve $ 539,000us-gaap_InventoryValuationReserves $ 0us-gaap_InventoryValuationReserves  
Capitalized inventory costs 110,000navb_OtherInventoryCapitalizedCostsDuration 2,400,000navb_OtherInventoryCapitalizedCostsDuration  
Inventory write offs 198,000navb_InventoryWriteDownToResearchAndDevelopment 298,000navb_InventoryWriteDownToResearchAndDevelopment  
Inventory Write-down $ 539,027us-gaap_InventoryWriteDown $ 0us-gaap_InventoryWriteDown $ 0us-gaap_InventoryWriteDown