Annual report pursuant to Section 13 and 15(d)

STOCK INCENTIVE PLANS AND SHARE-BASED COMPENSATION - Schedule of Options Outstanding and Exercisable, by Exercise Price Range (Details)

v2.4.1.9
STOCK INCENTIVE PLANS AND SHARE-BASED COMPENSATION - Schedule of Options Outstanding and Exercisable, by Exercise Price Range (Details) (USD $)
In Thousands, except Per Share data, unless otherwise specified
 12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]    
Stock Options Outstanding 4,944us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber 7,997us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Weighted- Average Exercise Price $ 1.47us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice $ 1.78us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Weighted- Average Remaining Contractual Life (Years) 1 year 8 months 20 days  
Stock Options Exercisable 4,916us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber  
Weighted- Average Exercise Price $ 1.46us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice  
Exercise Price Range 1    
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]    
Range of Exercise Prices, Minimum $ 0.11us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange1Member 		 
Range of Exercise Prices, Maximum $ 0.63us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange1Member 		 
Stock Options Outstanding 52us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange1Member 		 
Weighted- Average Exercise Price $ 0.49us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange1Member 		 
Weighted- Average Remaining Contractual Life (Years) 3 years 2 months 12 days  
Stock Options Exercisable 52us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange1Member 		 
Weighted- Average Exercise Price $ 0.49us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange1Member 		 
Exercise Price Range 2    
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]    
Range of Exercise Prices, Minimum $ 0.77us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange2Member 		 
Range of Exercise Prices, Maximum $ 0.98us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange2Member 		 
Stock Options Outstanding 3,019us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange2Member 		 
Weighted- Average Exercise Price $ 0.98us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange2Member 		 
Weighted- Average Remaining Contractual Life (Years) 1 year 3 months 0 days  
Stock Options Exercisable 3,019us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange2Member 		 
Weighted- Average Exercise Price $ 0.98us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange2Member 		 
Exercise Price Range 3    
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]    
Range of Exercise Prices, Minimum $ 1us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange3Member 		 
Range of Exercise Prices, Maximum $ 1.35us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange3Member 		 
Stock Options Outstanding 233us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange3Member 		 
Weighted- Average Exercise Price $ 1.15us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange3Member 		 
Weighted- Average Remaining Contractual Life (Years) 1 year 3 months 3 days  
Stock Options Exercisable 233us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange3Member 		 
Weighted- Average Exercise Price $ 1.15us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange3Member 		 
Exercise Price Range 4    
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]    
Range of Exercise Prices, Minimum $ 1.61us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange4Member 		 
Range of Exercise Prices, Maximum $ 2.17us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange4Member 		 
Stock Options Outstanding 204us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange4Member 		 
Weighted- Average Exercise Price $ 1.80us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange4Member 		 
Weighted- Average Remaining Contractual Life (Years) 0 years 5 months 5 days  
Stock Options Exercisable 204us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange4Member 		 
Weighted- Average Exercise Price $ 1.80us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange4Member 		 
Exercise Price Range 5    
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]    
Range of Exercise Prices, Minimum $ 2.52us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange5Member 		 
Range of Exercise Prices, Maximum $ 2.93us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange5Member 		 
Stock Options Outstanding 1,436us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange5Member 		 
Weighted- Average Exercise Price $ 2.53us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange5Member 		 
Weighted- Average Remaining Contractual Life (Years) 2 years 10 months 25 days  
Stock Options Exercisable 1,408us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange5Member 		 
Weighted- Average Exercise Price $ 2.53us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= qtm_ExercisePriceRange5Member