Note 7 - Income Taxes (Details Textual) - Greatbatch [Member] - Tax Matters Agreement [Member]	Jun. 30, 2017
Equity Issuance Limitations	30.00%
Asset Disposal Limitations	35.00%

The equity issuance limitations that are imposed on the entity regarding the issuance of equity compared to the total equity voting rights.

No definition available.

Name:	nvtr_EquityIssuanceLimitations
Namespace Prefix:	nvtr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant