Cover Page - shares	6 Months Ended
	Sep. 30, 2020	Oct. 26, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-13449
Entity Registrant Name	QUANTUM CORP /DE/
Entity Incorporation, State	DE
Entity Tax Identification Number	94-2665054
Entity Address, Street Address	224 Airport Parkway
Entity Address, Suite	Suite 550
Entity Address, City	San Jose
Entity Address, State	CA
Entity Address, Postal Zip Code	95110
City Area Code	(408)
Local Phone Number	944-4000
Title of each class	Common Stock, $0.01 par value per share
Trading Symbol	QMCO
Name of each exchange on which registered	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		40,740,212
Entity Central Index Key	0000709283
Current Fiscal Year End Date	--03-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Amendment Flag	false