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Income Taxes - Additional Information (Detail) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Operating Loss Carryforwards [Line Items]      
Effective tax rate 14.00%us-gaap_EffectiveIncomeTaxRateContinuingOperations    
Expected tax rate   19.00%vdsi_ExpectedAnnualizedTaxRate  
U.S. foreign tax credit     $ 5,516us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsForeign
Foreign net operating loss (NOL) carryforwards     4,366vdsi_ForeignNolCarryForwards
Other Foreign Deductible carryforwards     3,568vdsi_OtherForeignDeductibleCarryForwards
Expiry Date of other deductible carryforwards     2016 to 2021
U.S. net operating loss carryforwards     122vdsi_NetOperatingLossCarryforwardDomestic
2015 [Member]      
Operating Loss Carryforwards [Line Items]      
Foreign tax credit carryforwards expire amount     944vdsi_ForeignTaxCreditCarryforwardsExpireAmount
/ us-gaap_StatementScenarioAxis
= vdsi_TwoThousandFifteenMember
2023 And 2024 [Member]      
Operating Loss Carryforwards [Line Items]      
Foreign tax credit carryforwards expire amount     4,572vdsi_ForeignTaxCreditCarryforwardsExpireAmount
/ us-gaap_StatementScenarioAxis
= vdsi_TwoThousandTwentyThreeAndTwoThousandTwentyFourMember
Foreign Tax Authority [Member]      
Operating Loss Carryforwards [Line Items]      
Valuation allowance for deferred tax assets     $ 2,378us-gaap_TaxCreditCarryforwardValuationAllowance
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_ForeignCountryMember