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

Annual report pursuant to Section 13 and 15(d)

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								5 Months Ended	6 Months Ended			9 Months Ended		12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Aug. 18, 2017	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2017	Apr. 01, 2019	Apr. 18, 2017	Mar. 31, 2016
Line of Credit Facility [Line Items]
Shipping and handling fees																$ 9,100	$ 10,300		$ 10,400
Inventories	$ 3,400				$ 10,900											3,400	10,900
Reserves made for inventory																13,600	15,300
Deferred revenue outstanding	127,100															127,100
Deferred revenue, revenue recognized																83,400
Research and development costs	8,083	$ 7,907	$ 7,862	$ 8,261	8,605	$ 9,162	$ 10,190	$ 10,605		$ 16,123	$ 20,795	$ 20,795	$ 24,030	$ 29,957		32,113	38,562		44,379
Advertising expense																4,500	8,900	$ 9,700
Contribution to defined benefit plan																0	800		1,300
Cash from investing activities				(373)				165		(1,290)	(598)		1,187	(1,778)		235	(2,296)		(1,433)
Total of eash,cash equivalents and restricted cash	$ 16,855	$ 17,023	$ 11,828	$ 16,447	$ 17,207	$ 25,363	$ 37,046	$ 31,663		$ 11,828	$ 37,046	$ 31,663	$ 17,023	$ 25,363		$ 16,855	$ 17,207	$ 35,912	$ 35,912			$ 36,658
Common stock par value	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01		$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01		$ 0.01	$ 0.01	$ 0.01	$ 0.01		$ 0.01
Equity reverse stock split									1 for 8
Maximum [Member]
Line of Credit Facility [Line Items]
Credit period given to customers																90 days
Tenure of the contracts																10 years
Minimum [Member]
Line of Credit Facility [Line Items]
Credit period given to customers																30 days
Tenure of the contracts																1 year
Forecast [Member]
Line of Credit Facility [Line Items]
Deferred revenue, revenue recognized															$ 90,400
Percentage of revenue for which commitements are to be honoured															69.00%
Accounting Standards Update 2016-18 [Member]
Line of Credit Facility [Line Items]
Restricted cash and cash equivalents revised amount	$ 6,100				$ 6,300											$ 6,100	$ 6,300	$ 23,000	$ 23,000
Cash from investing activities																	16,600		20,200
Total of eash,cash equivalents and restricted cash					$ 17,200												$ 17,200	$ 35,900	$ 35,900			$ 36,700
Accounting Standards Update 2016-02 [Member] \| Subsequent Event [Member]
Line of Credit Facility [Line Items]
Operating lease liabilities																				$ 13,500
Right of use assets under operating leases																				$ 12,700
Sales Revenue, Net [Member]
Line of Credit Facility [Line Items]
Concentration risk, percentage																10.00%	10.00%
Accounts Receivable [Member]
Line of Credit Facility [Line Items]
Concentration risk, percentage																21.00%
Accounts Receivable [Member] \| Customer One [Member]
Line of Credit Facility [Line Items]
Concentration risk, percentage																	10.00%		11.00%