REVENUE AND MAJOR CUSTOMERS (Details)	3 Months Ended								12 Months Ended
	Mar. 28, 2020 USD ($) Customer	Dec. 28, 2019 USD ($)	Sep. 28, 2019 USD ($)	Jun. 29, 2019 USD ($)	Mar. 30, 2019 USD ($) Customer	Dec. 29, 2018 USD ($)	Sep. 29, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 28, 2020 USD ($) Customer	Mar. 28, 2020 USD ($) Customer	Mar. 30, 2019 USD ($) Customer	Mar. 31, 2018 USD ($) Customer
Revenue from External Customer [Line Items]
Contract with Customer, Asset, Gross, Current	$ 3,700,000								$ 3,700,000	$ 3,700,000
Revenue, Remaining Performance Obligation, Current	148,700								148,700	148,700
Net revenues	403,043,000	$ 384,471,000	$ 461,709,000	$ 447,767,000	$ 468,488,000	$ 501,669,000	$ 483,069,000	$ 221,309,000	1,696,990,000	1,696,990,000	$ 1,674,535,000	$ 856,903,000
Contract with Customer, Liability	208,500,000				$ 193,900,000				$ 208,500,000	208,500,000	193,900,000	$ 3,000,000.0
Contract with Customer, Liability, Percentage Of Revenue					11.60%				12.30%			1.00%
Number of major customers, ten percent or greater, net accounts receivable | Customer												1
Capitalized Contract Cost, Gross	2,700,000								$ 2,700,000	2,700,000
Revenue, Remaining Performance Obligation, Noncurrent	64,500								64,500	64,500
Revenue, Remaining Performance Obligation, Amount	$ 213,200								213,200	213,200
Contract with Customer, Liability, Revenue Recognized									133,200,000
Product
Revenue from External Customer [Line Items]
Net revenues									1,432,736,000		1,510,770,000	$ 856,903,000
Product | U.S.
Revenue from External Customer [Line Items]
Net revenues									708,566,000		729,930,000	434,053,000
Product | Europe and Africa
Revenue from External Customer [Line Items]
Net revenues									398,721,000		432,899,000	250,762,000
Product | Asia Pacific
Revenue from External Customer [Line Items]
Net revenues									221,912,000		245,499,000	99,779,000
Product | Americas, excluding U.S.
Revenue from External Customer [Line Items]
Net revenues									103,537,000		102,442,000	72,309,000
Product | Total international net revenues [Member]
Revenue from External Customer [Line Items]
Net revenues									724,170,000		780,840,000	422,850,000
Enterprise Headset [Member]
Revenue from External Customer [Line Items]
Net revenues										773,186,000	910,699,000	856,903,000
Voice
Revenue from External Customer [Line Items]
Net revenues										377,059,000	344,586,000	0
Video
Revenue from External Customer [Line Items]
Net revenues										282,491,000	255,485,000	0
Service
Revenue from External Customer [Line Items]
Net revenues									264,254,000	$ 264,254,000	163,765,000	0
Service | U.S.
Revenue from External Customer [Line Items]
Net revenues									102,103,000		59,615,000
Service | Europe and Africa
Revenue from External Customer [Line Items]
Net revenues									66,900,000		43,991,000
Service | Asia Pacific
Revenue from External Customer [Line Items]
Net revenues									73,424,000		43,382,000
Service | Americas, excluding U.S.
Revenue from External Customer [Line Items]
Net revenues									21,827,000		16,777,000
Service | Total international net revenues [Member]
Revenue from External Customer [Line Items]
Net revenues									$ 162,151,000		$ 104,150,000	$ 0
Net Revenues [Member] | Customer concentration risk
Revenue from External Customer [Line Items]
Number of major customers, ten percent or greater, net revenues | Customer									2		2	1
Net Revenues [Member] | Customer concentration risk | Ingram Micro [Member]
Revenue from External Customer [Line Items]
Concentration risk percentage									17.30%		11.40%	10.90%
Net Revenues [Member] | Customer concentration risk | ScanSource [Member]
Revenue from External Customer [Line Items]
Concentration risk percentage									19.80%		16.00%
Accounts receivable | Customer concentration risk
Revenue from External Customer [Line Items]
Number of major customers, ten percent or greater, net accounts receivable | Customer					3						3
Accounts receivable | Customer concentration risk | Ingram Micro [Member]
Revenue from External Customer [Line Items]
Concentration risk percentage									22.20%		21.30%
Accounts receivable | Customer concentration risk | Scansource, D&H Distributors And Ingram Micro [Member]
Revenue from External Customer [Line Items]
Number of major customers, ten percent or greater, net accounts receivable | Customer	3								3	3
Accounts receivable | Customer concentration risk | D&H Distributors [Member]
Revenue from External Customer [Line Items]
Concentration risk percentage									10.90%		10.90%
Accounts receivable | Customer concentration risk | ScanSource [Member]
Revenue from External Customer [Line Items]
Concentration risk percentage									17.30%		19.20%
Accounts receivable | Customer concentration risk | Synnex Corp. [Member]
Revenue from External Customer [Line Items]
Concentration risk percentage									15.60%
Minimum
Revenue from External Customer [Line Items]
Revenue From Contracts With Customers, Credit Term									30 years
Maximum
Revenue from External Customer [Line Items]
Revenue From Contracts With Customers, Credit Term									90 years