REVENUE AND MAJOR CUSTOMERS (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($) Customer	Sep. 30, 2016 USD ($) Customer	Sep. 30, 2017 USD ($) Customer	Sep. 30, 2016 USD ($)	Mar. 31, 2017 Customer	Mar. 31, 2016 Customer
Revenue from External Customer [Line Items]
Net revenues	$ 210,300	$ 216,183	$ 414,226	$ 439,289
US [Member]
Revenue from External Customer [Line Items]
Net revenues	111,095	119,062	219,905	247,300
Europe and Africa [Member]
Revenue from External Customer [Line Items]
Net revenues	56,325	51,422	111,141	105,489
Asia Pacific [Member]
Revenue from External Customer [Line Items]
Net revenues	24,227	28,588	48,111	54,815
Americas, excluding U.S. [Member]
Revenue from External Customer [Line Items]
Net revenues	18,653	17,111	35,069	31,685
Total international net revenues [Member]
Revenue from External Customer [Line Items]
Net revenues	99,205	97,121	194,321	191,989
Enterprise [Member]
Revenue from External Customer [Line Items]
Net revenues	162,907	154,542	317,512	310,439
Consumer [Member]
Revenue from External Customer [Line Items]
Net revenues	$ 47,393	$ 61,641	$ 96,714	$ 128,850
Net Revenues [Member] | Customer Concentration Risk [Member] | Ingram Micro [Member]
Revenue from External Customer [Line Items]
Number of major customers, ten percent or greater, net revenues | Customer	1	1				1
Concentration risk percentage	12.40%	10.70%	12.20%	10.40%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Ingram Micro [Member]
Revenue from External Customer [Line Items]
Number of major customers, ten percent or greater, net accounts receivable | Customer	2		2		1
Concentration risk percentage			15.40%		17.60%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | D&H Distributors [Member]
Revenue from External Customer [Line Items]
Concentration risk percentage			11.50%