REVENUE AND MAJOR CUSTOMERS (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 26, 2020 USD ($) Customer	Dec. 28, 2019 USD ($) Customer	Dec. 26, 2020 USD ($) Customer	Dec. 28, 2019 USD ($)	Mar. 28, 2020 USD ($) Customer
Revenue from External Customer [Line Items]
Contract with customer, asset, before allowance for credit loss, current	$ 6,300,000		$ 6,300,000		$ 3,700,000
Remaining performance obligation, current	147,800		147,800
Net revenues	484,685,000	$ 384,471,000	$ 1,251,375,000	$ 1,293,947,000
Revenue from contracts with customers, percentage associated with non-cancellable maintenance and support contracts			90.00%
Contract with customer, liability	216,400,000		$ 216,400,000		$ 208,500,000
Capitalized contract cost, gross	4,800,000		4,800,000
Remaining performance obligation, noncurrent	69,500		69,500
Remaining performance obligation	217,300		217,300
Revenue recognized	50,900,000
Amortization of capitalized contract costs	0		1,600,000
Headset
Revenue from External Customer [Line Items]
Net revenues	240,908,000	167,280,000	618,498,000	592,222,000
Product
Revenue from External Customer [Line Items]
Net revenues	420,711,000	316,633,000	1,059,846,000	1,094,515,000
Product | U.S.
Revenue from External Customer [Line Items]
Net revenues	169,812,000	149,652,000	473,633,000	536,368,000
Product | Europe and Africa
Revenue from External Customer [Line Items]
Net revenues	164,896,000	88,356,000	357,389,000	301,134,000
Product | Asia Pacific
Revenue from External Customer [Line Items]
Net revenues	57,481,000	54,920,000	155,460,000	180,993,000
Product | Americas, excluding U.S.
Revenue from External Customer [Line Items]
Net revenues	28,522,000	23,705,000	73,364,000	76,020,000
Product | Total international net revenues
Revenue from External Customer [Line Items]
Net revenues	250,899,000	166,981,000	586,213,000	558,147,000
Voice
Revenue from External Customer [Line Items]
Net revenues	67,076,000	79,494,000	156,682,000	281,794,000
Video
Revenue from External Customer [Line Items]
Net revenues	112,727,000	69,859,000	284,666,000	220,499,000
Service
Revenue from External Customer [Line Items]
Net revenues	63,974,000	67,838,000	191,529,000	199,432,000
Service | U.S.
Revenue from External Customer [Line Items]
Net revenues	23,601,000	26,204,000	71,839,000	77,442,000
Service | Europe and Africa
Revenue from External Customer [Line Items]
Net revenues	16,533,000	17,575,000	48,545,000	50,749,000
Service | Asia Pacific
Revenue from External Customer [Line Items]
Net revenues	19,342,000	18,710,000	57,196,000	54,938,000
Service | Americas, excluding U.S.
Revenue from External Customer [Line Items]
Net revenues	4,498,000	5,349,000	13,949,000	16,303,000
Service | Total international net revenues
Revenue from External Customer [Line Items]
Net revenues	$ 40,373,000	$ 41,634,000	$ 119,690,000	$ 121,990,000
Net Revenues | Customer Concentration Risk
Revenue from External Customer [Line Items]
Number of major customers, 10% or greater, net revenues | Customer	2	2
Net Revenues | Customer Concentration Risk | ScanSource
Revenue from External Customer [Line Items]
Concentration risk percentage	17.10%	19.20%	10.50%	19.50%
Net Revenues | Customer Concentration Risk | Ingram Micro
Revenue from External Customer [Line Items]
Concentration risk percentage	19.10%	12.70%	12.60%	15.70%
Accounts Receivable | Customer Concentration Risk
Revenue from External Customer [Line Items]
Number of major customers, ten percent or greater, net accounts receivable | Customer	2		2		3
Accounts Receivable | Customer Concentration Risk | ScanSource
Revenue from External Customer [Line Items]
Concentration risk percentage			19.60%		17.30%
Accounts Receivable | Customer Concentration Risk | Ingram Micro
Revenue from External Customer [Line Items]
Concentration risk percentage			21.50%		22.20%
Accounts Receivable | Customer Concentration Risk | Synnex Corp.
Revenue from External Customer [Line Items]
Concentration risk percentage					15.60%
Minimum
Revenue from External Customer [Line Items]
Credit term			30 days
Maximum
Revenue from External Customer [Line Items]
Credit term			90 days