Litigation, Claims, and Assessments - Additional Information (Details)	Sep. 21, 2016 USD ($)	Jul. 26, 2016 patent	Mar. 11, 2016 inter_parts_review patent	Feb. 26, 2016 inter_parts_review patent	Jan. 14, 2016 inter_parts_review patent	Dec. 15, 2015 inter_parts_review patent	Dec. 10, 2015 patent	Sep. 10, 2015 inter_parts_review	Aug. 20, 2015 inter_parts_review	Aug. 04, 2015 USD ($)	Sep. 07, 2016 USD ($)
Finjan, Inc. v. Blue Coat Systems, Inc
Loss Contingencies [Line Items]
Damages awarded | $										$ 39,500,000
Finjan, Inc. v. Sophos Inc
Loss Contingencies [Line Items]
Damages awarded | $	$ 15,000,000
Finjan, Inc. v. Blue Coat Systems LLC
Loss Contingencies [Line Items]
Number of Inter Parts Review | inter_parts_review						5
Number of patents asserted						7
Finjan, Inc. v. Symantec Corp
Loss Contingencies [Line Items]
Number of Inter Parts Review | inter_parts_review								11	8
Finjan, Inc. v. Symantec Corp | Denied
Loss Contingencies [Line Items]
Number of Inter Parts Review | inter_parts_review			2	2	6
Number of patents asserted			10	8	5
Finjan, Inc. v. Palo Alto Networks, Inc
Loss Contingencies [Line Items]
Number of patents asserted							10
Finjan, Inc. v. ESET, LLC
Loss Contingencies [Line Items]
Number of patents asserted		6
Number of patents first-to-file		5
Blue Coat Systems, Inc | Finjan, Inc. v. Blue Coat Systems, Inc
Loss Contingencies [Line Items]
Bond amount | $											$ 40,086,172.78