Quantum Corporation Annual report pursuant to Section 13 and 15(d)

RESTATEMENT - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended								6 Months Ended			9 Months Ended		12 Months Ended
RESTATEMENT - Narrative (Details) - USD ($) $ in Thousands	Apr. 02, 2016	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Restated per tax income loss		$ (7,773)	$ (3,948)	$ (20,640)	$ (8,060)	$ (23,881)	$ (12,326)	$ (4,871)	$ (5,381)	$ (28,700)	$ (10,252)	$ (10,252)	$ (32,648)	$ (22,578)	$ (40,421)	$ (46,459)	$ (752)
Restated net income loss		$ (9,410)	$ (4,285)	$ (21,617)	$ (7,485)	$ (23,929)	$ (10,199)	(5,099)	(4,119)	$ (29,103)	(9,218)	$ (9,218)	$ (33,387)	$ (19,417)	$ (42,797)	$ (43,346)	(2,408)
Restatement Adjustment [Member]
Adjustments to retained earnings	$ (12,500)																(17,213)
Adjustments to AOCI	$ (4,800)
Restated per tax income loss								2,493	(468)		2,026						(5,509)
Restated net income loss								$ 2,764	$ (444)		$ 2,319						$ (6,053)

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.