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Investments - Non-Marketable Equity Securities (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Mar. 31, 2013
Mar. 29, 2015
Mar. 30, 2014
Non-marketable equity securities [Abstract]      
Purchase of common stock of a privately-held company   $ 4.0us-gaap_CostMethodInvestmentsOriginalCost  
Other-than temporary impairment loss during period 1.7us-gaap_CostmethodInvestmentsOtherThanTemporaryImpairment    
Carrying value of non-marketable equity securities   $ 4.0us-gaap_CostMethodInvestments $ 0us-gaap_CostMethodInvestments
Non-marketable Equity Securities      
Non-marketable equity securities [Abstract]      
Number of non-marketable private equity investments impaired (securities) 2idti_OtherThanTemporaryImpairmentLossesInvestmentsNumberOfImpairedSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember