Marketable Securities (Narrative) (Details) (USD $)	Dec. 31, 2013	Mar. 31, 2013
Schedule of Investments [Line Items]
Gross unrealized losses	$ 497,711	$ 13,342
Municipal Bonds [Member]
Schedule of Investments [Line Items]
Gross unrealized losses	$ 4,011	$ 9,155

Amount of accumulated pre-tax unrealized loss on securities classified as available-for-sale impacting investments.

No definition available.

Name:	nvec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAggregateLossesAccumulatedInInvestments
Namespace Prefix:	nvec_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant