BUSINESS ACQUISITONS - SCHEDULE OF GENBAND PURCHASE PRICE ALLOCATION (Details) - USD ($)		12 Months Ended
	Oct. 27, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash consideration:
Net cash consideration		$ 42,951,000	$ 20,669,000	$ 10,897,000
Fair value of Sonus stock issued	$ 413,982,000
Intangible assets:
Goodwill		$ 335,716,000	$ 49,393,000	$ 40,310,000
GENBAND
Cash consideration:
Repayment of GENBAND long-term debt and accrued interest, related party	47,973,000
Payment of GENBAND management fees due to majority shareholder	10,302,000
Less cash acquired	(15,324,000)
Net cash consideration	42,951,000
Promissory note issued to GENBAND equity holders	22,500,000.0
Fair value of total consideration	479,433,000
Fair value of assets acquired and liabilities assumed:
Current assets, net of cash acquired	99,126,000
Property and equipment	16,770,000
Intangible assets:
Goodwill	285,825,000
Other noncurrent assets	6,732,000
Revolving credit facility	(17,930,000)
Deferred revenue	(32,390,000)
Other current liabilities	(80,023,000)
Deferred revenue, net of current	(6,804,000)
Other long-term liabilities	(28,673,000)
Assets acquired and liabilities assumed	479,433,000
GENBAND | In-process research and development
Intangible assets:
Finite-lived intangibles	5,600,000
GENBAND | Developed Technology Rights [Member]
Intangible assets:
Finite-lived intangibles	129,000,000
GENBAND | Customer relationships
Intangible assets:
Finite-lived intangibles	101,300,000
GENBAND | Trade names
Intangible assets:
Finite-lived intangibles	$ 900,000