Incapsula - Additional Information (Detail) - USD ($) $ in Thousands		1 Months Ended				12 Months Ended
	Nov. 05, 2009	Mar. 31, 2014	Jan. 31, 2012	Jul. 31, 2011	Mar. 31, 2010	Dec. 31, 2015	Dec. 31, 2014
Subsidiary or Equity Method Investee [Line Items]
Non-controlling interest reclassified to additional paid-in capital		$ 2,800					$ 0
Incapsula Acquisition [Member]
Subsidiary or Equity Method Investee [Line Items]
Amount paid for remaining outstanding capital stock		$ 7,700
Business acquisition, shares issued		124,088				34,420
Series A Convertible Preferred Stock [Member] | Incapsula [Member]
Subsidiary or Equity Method Investee [Line Items]
Equity method investments, shares	5,000,000				6,666,666
Ownership interest	58.00%				76.00%
Cash consideration					$ 3,000
Series A-1 Preferred Stock [Member] | Incapsula [Member]
Subsidiary or Equity Method Investee [Line Items]
Equity method investments, shares			4,375,000	4,375,000
Ownership interest			85.00%	82.00%
Cash consideration			$ 3,500	$ 3,500