PRODUCT AND GEOGRAPHIC INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting, Revenue Reconciling Item [Line Items]
Products									$ 209,461	$ 283,110	$ 336,371
Services									209,542	228,820	169,224
Total net revenues	$ 107,258	$ 105,265	$ 102,373	$ 104,107	$ 115,295	$ 119,019	$ 134,069	$ 143,547	$ 419,003	511,930	505,595
Minimum percentage of revenue not attained by any individual country other than the country of domicile									10.00%
Long-lived assets	32,718				41,756				$ 32,718	41,756
United States [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total net revenues									161,155	186,658	185,109
Long-lived assets	24,292				29,970				24,292	29,970
Other Americas [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total net revenues									27,031	38,824	37,081
Europe, Middle East and Africa [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total net revenues									163,059	206,605	206,192
Asia-Pacific [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total net revenues									67,758	79,843	77,213
Other Countries [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Long-lived assets	$ 8,426				$ 11,786				8,426	11,786
Video products and solutions net revenues [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Products									114,787	155,408	201,559
Audio products and solutions net revenues [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Products									$ 94,674	$ 127,702	$ 134,812