GOODWILL AND INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Intangible Assets and Goodwill [Line Items]
Amortization of intangibles		$ 5,267	$ 6,083	$ 6,663
Intangible Assets, Net[Abstract]
Total intangible assets, Gross		60,251	59,911
Accumulated amortization		(39,099)	(34,492)
Total Finite Lived Intangible Assets, Net	[1]	15,201
Total Intangible Assets, Net		$ 21,152	25,419
Minimum [Member]
Intangible Assets and Goodwill [Line Items]
Useful life (in years)		2 years
Maximum [Member]
Intangible Assets and Goodwill [Line Items]
Useful life (in years)		12 years
Developed technology
Intangible Assets, Net[Abstract]
Finite-Lived Intangible Assets, Gross		$ 33,270	33,270
Accumulated amortization		(22,464)	(19,211)
Total Finite Lived Intangible Assets, Net		10,806	14,059
Customer relationships [Member]
Intangible Assets, Net[Abstract]
Finite-Lived Intangible Assets, Gross		20,030	20,030
Accumulated amortization		(16,520)	(14,621)
Total Finite Lived Intangible Assets, Net		3,510	5,409
Technology licenses [Member]
Intangible Assets, Net[Abstract]
Finite-Lived Intangible Assets, Gross		1,000	0
Accumulated amortization		(115)	0
Total Finite Lived Intangible Assets, Net		885	0
Leases, Acquired-in-Place [Member]
Intangible Assets, Net[Abstract]
Finite-Lived Intangible Assets, Gross		0	660
Accumulated amortization		0	(660)
Total Finite Lived Intangible Assets, Net		0	0
Domain name
Intangible Assets, Net[Abstract]
Indefinite-lived intangible assets		1,261	1,261
In Process Research and Development [Member]
Intangible Assets and Goodwill [Line Items]
Finite-lived intangible assets		4,690
Intangible Assets, Net[Abstract]
Finite-Lived Intangible Assets, Gross		4,690	4,690
Total Finite Lived Intangible Assets, Net		$ 4,690	$ 4,690

[1] The total above excludes $4.7 million of in-process R&D which will be amortized upon completion of development over the estimated useful life of the technology.