Annual report pursuant to Section 13 and 15(d)

INTANGIBLE ASSETS AND GOODWILL - Narrative (Details)

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INTANGIBLE ASSETS AND GOODWILL - Narrative (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Finite-Lived Intangible Assets [Line Items]    
Estimated useful life (in years) 6 years 8 months 17 days  
Write off of fully amortized intangible assets $ 9.8qtm_WriteOffOfFullyAmortizedFiniteLivedIntangibleAssets $ 31.0qtm_WriteOffOfFullyAmortizedFiniteLivedIntangibleAssets
IPR&D transferred to amortizable purchased technology intangible assets   $ 0.1qtm_IPRDTransferredToAmortizableIntangibleAssets
Minimum    
Finite-Lived Intangible Assets [Line Items]    
Estimated useful life (in years) 1 year  
Maximum    
Finite-Lived Intangible Assets [Line Items]    
Estimated useful life (in years) 8 years