Commitments and Contingencies - Operating Lease - New Boston lease (Details) - USD ($) $ in Thousands	1 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	May 31, 2019	Dec. 31, 2018
Maturity of the lease liability was as follows (in thousands):
2020		$ 32
2021		32
2022		32
2023		32
2024		16
Total lease payments		144
Less effect of discounting		(28)
Total		116
Short-term portion	$ (20)	(22)
Long-term portion	$ 106	$ 94
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	nrbo:LongTermDebtAndLeaseObligationOtherThanConverti	Long-term Debt and Lease Obligation Other Than Convertible Notes
Agreement Term			5 years
Right-of-use assets	$ 126	$ 150		$ 9
Lease liability		116
Head Quarters in Boston Lease [Member]
Maturity of the lease liability was as follows (in thousands):
2020		204
2021		21
Total lease payments		225
Total		0
Agreement Term	1 year
Monthly rental cost	$ 21
Right-of-use assets		0
Lease liability		$ 0
Rent concessions granted by the landlord	$ 32