Quarterly report pursuant to Section 13 or 15(d)

NET INCOME (LOSS) PER SHARE (Computation of Net Income (Loss) Per Share) (Details)

v2.4.1.9
NET INCOME (LOSS) PER SHARE (Computation of Net Income (Loss) Per Share) (Details) (USD $)
In Thousands, except Per Share data, unless otherwise specified
3 Months Ended 9 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Earnings Per Share [Abstract]        
Net income (loss) $ 6,931us-gaap_NetIncomeLoss $ (2,458)us-gaap_NetIncomeLoss $ 3,855us-gaap_NetIncomeLoss $ (7,070)us-gaap_NetIncomeLoss
Adjustment for interest expense on convertible subordinated notes, net of taxes 902us-gaap_InterestOnConvertibleDebtNetOfTax 0us-gaap_InterestOnConvertibleDebtNetOfTax 0us-gaap_InterestOnConvertibleDebtNetOfTax 0us-gaap_InterestOnConvertibleDebtNetOfTax
Income (loss) for purposes of computing income (loss) per diluted share $ 7,833us-gaap_NetIncomeLossAttributableToParentDiluted $ (2,458)us-gaap_NetIncomeLossAttributableToParentDiluted $ 3,855us-gaap_NetIncomeLossAttributableToParentDiluted $ (7,070)us-gaap_NetIncomeLossAttributableToParentDiluted
Weighted average shares:        
Basic 255,860us-gaap_WeightedAverageNumberOfSharesOutstandingBasic 248,135us-gaap_WeightedAverageNumberOfSharesOutstandingBasic 253,773us-gaap_WeightedAverageNumberOfSharesOutstandingBasic 246,183us-gaap_WeightedAverageNumberOfSharesOutstandingBasic
Dilutive shares from stock plans 4,493qtm_DilutiveCommonShareEquivalentsFromStockPlans 0qtm_DilutiveCommonShareEquivalentsFromStockPlans 4,034qtm_DilutiveCommonShareEquivalentsFromStockPlans 0qtm_DilutiveCommonShareEquivalentsFromStockPlans
Dilutive shares from convertible subordinated notes 42,502qtm_DilutiveCommonShareEquivalentsFromEspp 0qtm_DilutiveCommonShareEquivalentsFromEspp 0qtm_DilutiveCommonShareEquivalentsFromEspp 0qtm_DilutiveCommonShareEquivalentsFromEspp
Diluted 302,855us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding 248,135us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding 257,807us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding 246,183us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding
Basic net income (loss) per share $ 0.03us-gaap_EarningsPerShareBasic $ (0.01)us-gaap_EarningsPerShareBasic $ 0.02us-gaap_EarningsPerShareBasic $ (0.03)us-gaap_EarningsPerShareBasic
Diluted net income (loss) per share $ 0.03us-gaap_EarningsPerShareDiluted $ (0.01)us-gaap_EarningsPerShareDiluted $ 0.01us-gaap_EarningsPerShareDiluted $ (0.03)us-gaap_EarningsPerShareDiluted