BALANCE SHEET DETAILS - Schedule of Service Parts Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Balance Sheet Related Disclosures [Abstract]
Finished goods	$ 14,851	$ 16,381
Component parts	4,998	5,026
Service parts inventories, net	$ 19,849	$ 21,407

Carrying amount of completed service parts merchandise or goods expected to be sold within one year or operating cycle, if longer.

No definition available.

Name:	qtm_ServicePartsInventoriesFinishedGoods
Namespace Prefix:	qtm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant