INVENTORIES - Schedule of Service Parts Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Mar. 31, 2017
Service parts inventories:
Finished goods	$ 14,802	$ 14,851
Component parts	5,113	4,998
Total service parts inventories	$ 19,915	$ 19,849

Carrying amount as of the balance sheet date of component parts held by the company as service parts.

No definition available.

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