LICENSE, SETTLEMENT AND RELEASE AGREEMENT (Details) - Licensing Agreements - USD ($) $ in Thousands										3 Months Ended		9 Months Ended
	Jan. 13, 2017	Jun. 30, 2016	Jun. 06, 2016	Jun. 03, 2016	Jan. 15, 2016	Dec. 31, 2015	Dec. 30, 2015	Jan. 16, 2015	Sep. 24, 2014	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Jan. 03, 2018	Jan. 04, 2017	Sep. 01, 2016	Jun. 27, 2016	Apr. 07, 2015
Finite-Lived Intangible Assets [Line Items]
Receivable related to license agreement									$ 1,000
License revenue										$ 1,000	$ 1,650
License fee receivable									8,000
License agreement installment					$ 2,000			$ 2,000	$ 3,000
Forecast
Finite-Lived Intangible Assets [Line Items]
License agreement installment	$ 1,000
European Cloud-Based Network Security Firm
Finite-Lived Intangible Assets [Line Items]
Sale of patent in license agreement		$ 565
Proofpoint and Amorize Technologies
Finite-Lived Intangible Assets [Line Items]
Sale of patent in license agreement				$ 10,900
Cash received from license agreement			$ 4,300
Receivable related to license agreement				6,600
License revenue		$ 4,300
License fee receivable				$ 10,900
Proofpoint and Amorize Technologies | Forecast
Finite-Lived Intangible Assets [Line Items]
Receivable related to license agreement													$ 3,300	$ 3,300
United States-based Third Party
Finite-Lived Intangible Assets [Line Items]
Sale of patent in license agreement							$ 3,650
Cash received from license agreement							$ 1,000
Receivable related to license agreement															$ 1,000	$ 1,650
License revenue						$ 1,000
License fee receivable						$ 3,650
F-Secure Corporation
Finite-Lived Intangible Assets [Line Items]
Receivable related to license agreement																	$ 300
Fully-paid, non-exclusive field of use license term (in years)												2 years
License revenue												$ 700
License fee receivable																	$ 1,000