Deferred Warranty Revenue and Warranty Reserve - Deferred Warranty Revenue (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014
Guarantees [Abstract]
2015	$ 38
2016	24
2017	18
2018	9
2019	3
Total	$ 92

The total amount of deferred revenue that will be recognized in future periods.

No definition available.

Name:	vdsi_DeferredRevenueEstimatedRevenueExpectedRecognized
Namespace Prefix:	vdsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Deferred revenue estimated revenue expected recognised fiscal year.

No definition available.

Name:	vdsi_DeferredRevenueEstimatedRevenueExpectedRecognizedFiscalYear
Namespace Prefix:	vdsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Deferred revenue estimated revenue expected recognized year five.

No definition available.

Name:	vdsi_DeferredRevenueEstimatedRevenueExpectedRecognizedYearFive
Namespace Prefix:	vdsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Deferred revenue estimated revenue expected recognized year four.

No definition available.

Name:	vdsi_DeferredRevenueEstimatedRevenueExpectedRecognizedYearFour
Namespace Prefix:	vdsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Deferred revenue estimated revenue expected recognized year three.

No definition available.

Name:	vdsi_DeferredRevenueEstimatedRevenueExpectedRecognizedYearThree
Namespace Prefix:	vdsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Deferred revenue estimated revenue expected recognised year two.

No definition available.

Name:	vdsi_DeferredRevenueEstimatedRevenueExpectedRecognizedYearTwo
Namespace Prefix:	vdsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration