COMMITMENTS AND CONTINGENCIES - Narrative (Details) $ in Thousands					3 Months Ended		6 Months Ended
	Aug. 24, 2018 USD ($)	Aug. 24, 2017 USD ($) patent	Apr. 21, 2017 USD ($) installment	Nov. 21, 2013 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) installment lease	Jun. 30, 2018 USD ($)	Apr. 01, 2019 USD ($)	Jan. 01, 2019 USD ($)	Jul. 19, 2018	Mar. 31, 2018 USD ($)
Schedule of Investments [Line Items]
Annual rent expense							$ 700
Percentage increase in annual rent payment											3.50%
Number of sub-leases | lease							2
Operating lease payments							$ 400
Right of use assets					$ 2,481		2,481
Operating lease liabilities					$ 2,561		$ 2,561
Weighted average remaining lease term					4 years		4 years
Weighted average discount rate					11.00%		11.00%
Payments made							$ 0	$ 1,000
Avira, Inc.
Schedule of Investments [Line Items]
Sale of patent in license agreement			$ 3,900				$ 1,200
Number of quarterly installments | installment			12				4
Installment amount payable			$ 300
Payable period of agreement			3 years
Venture Capital Funds
Schedule of Investments [Line Items]
Capital commitment				$ 5,000	$ 1,300		$ 1,300
Percentage of limited partnership interest (less than)				10.00%
Cash call									$ 500
Patents | Finjan Blue
Schedule of Investments [Line Items]
Number of assets transferred | patent		41
Patents acquired		$ 8,500
Payments made	$ 1,000	2,000
Cash payable over subsequent four years		$ 6,500			5,500		5,500
Useful life of intangible asset		4 years
Patents												$ 7,000
Adjustment, present value												$ 1,400
Accretion expense					100	$ 100	200	500
Amortization of intangible assets					$ 500	$ 600	$ 1,000	$ 800
Accounting Standards Update 2016-02
Schedule of Investments [Line Items]
Right of use assets										$ 2,700
Operating lease liabilities										$ 2,800