Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Summary of Company's operating segments
Net revenue	$ 26,344	$ 19,738	$ 72,416	$ 54,987
Operating loss	(1,662)	(2,601)	(6,262)	(8,522)
Provision for income taxes	262	205	642	471
Net loss	(1,859)	(2,691)	(6,663)	(8,773)
Depreciation and amortization			1,312	1,123
Stock-based compensation			3,596	1,154
Total assets	140,779		140,779		133,542	[1]
Imperva [Member]
Summary of Company's operating segments
Net revenue	26,122	19,711	71,941	54,952
Operating loss	(957)	(1,884)	(4,238)	(6,617)
Provision for income taxes	224	199	597	443
Net loss	(1,134)	(2,073)	(4,783)	(7,254)
Depreciation and amortization	427	394	1,237	1,101
Stock-based compensation	1,755	567	3,575	1,137
Total assets	136,401	39,028	136,401	39,028
Incapsula [Member]
Summary of Company's operating segments
Net revenue	222	27	475	35
Operating loss	(705)	(717)	(2,024)	(1,905)
Provision for income taxes	38	6	45	28
Net loss	(857)	(796)	(2,247)	(1,977)
Depreciation and amortization	35	9	75	22
Stock-based compensation	7	11	21	17
Total assets	$ 4,378	$ 3,437	$ 4,378	$ 3,437

[1] The Condensed Consolidated Balance Sheet as of December 31, 2011 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.