Reduction in Force (Details) (USD $)	1 Months Ended	3 Months Ended
Reduction in Force (Details) (USD $)	Mar. 31, 2015 employee	Mar. 31, 2015	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	$ 1,055,132us-gaap_RestructuringReserve	$ 1,055,132us-gaap_RestructuringReserve	$ 449,351us-gaap_RestructuringReserve
Restructuring Costs Related to Equity Awards		372,000
Restructuring Reserve
Number of employees terminated, staff	7navb_NumberofEmployeesTerminatedStaff
Number of employees terminated, executives	4
Restructuring costs		1,400,000us-gaap_RestructuringCosts
Separation payments, including payroll taxes
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	964,013	964,013
Estimated cost of continuing healthcare coverage
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	$ 91,119	$ 91,119