Imperva Inactive 10-Q12 Nov 132013 Q3 Quarterly reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
Document and Entity Information	Sep. 30, 2013	Nov. 01, 2013
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'IMPV	'
Entity Registrant Name	'IMPERVA INC	'
Entity Central Index Key	'0001364962	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	24,962,578

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
CURRENT ASSETS:	'	'
Cash and cash equivalents	$70,640	$59,201	[1]
Short-term investments	36,185	43,126	[1]
Restricted cash	34	591	[1]
Accounts receivable, net of allowance for doubtful accounts of $383 and $412 as of September 30, 2013 and December 31, 2012, respectively	36,652	35,576	[1]
Inventory	541	328	[1]
Deferred tax assets	613	597	[1]
Prepaid expenses and other current assets	4,585	4,356	[1]
Total current assets	149,250	143,775	[1]
Property and equipment, net	5,333	5,515	[1]
Severance pay fund	3,687	3,150	[1]
Restricted cash	1,252	753	[1]
Other assets	776	764	[1]
TOTAL ASSETS	160,298	153,957	[1]
CURRENT LIABILITIES:	'	'
Accounts payable	3,055	3,789	[1]
Accrued compensation and benefits	11,805	9,258	[1]
Accrued and other current liabilities	3,893	4,323	[1]
Deferred revenue	35,834	33,609	[1]
Total current liabilities	54,587	50,979	[1]
Other liabilities	2,322	2,638	[1]
Deferred revenue	16,814	12,682	[1]
Accrued severance pay	3,980	3,427	[1]
TOTAL LIABILITIES	77,703	69,726	[1]
Commitments and Contingencies (Note 7)	'	'	[1]
STOCKHOLDERS' EQUITY:	'	'
Preferred stock, $0.0001 par value - 5,000,000 shares authorized, no shares issued and outstanding as of September 30, 2013 and December 31, 2012	'	'
Common stock, $0.0001 par value - 145,000,000 shares authorized, 24,959,203 and 24,296,076 shares issued and outstanding as of September 30, 2013 and December 31, 2012, respectively	2	2	[1]
Additional paid-in capital	173,479	157,989	[1]
Accumulated deficit	-89,266	-73,517	[1]
Accumulated other comprehensive income	253	861	[1]
TOTAL IMPERVA, INC. STOCKHOLDERS' EQUITY	84,468	85,335	[1]
Noncontrolling interest	-1,873	-1,104	[1]
TOTAL STOCKHOLDERS' EQUITY	82,595	84,231	[1]
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$160,298	$153,957	[1]

[1]	The Condensed Consolidated Balance Sheet as of December 31, 2012 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.

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]	'	'
Allowance for doubtful accounts	$383	$412	[1]
Preferred stock, par value	$0.00	$0.00	[1]
Preferred stock, shares authorized	5,000,000	5,000,000	[1]
Preferred stock, shares issued	0	0	[1]
Preferred stock, shares outstanding	0	0	[1]
Common stock, par value	$0.00	$0.00	[1]
Common stock, shares authorized	145,000,000	145,000,000	[1]
Common stock, shares issued	24,959,203	24,296,076	[1]
Common stock, shares outstanding	24,959,203	24,296,076	[1]

[1]	The Condensed Consolidated Balance Sheet as of December 31, 2012 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.

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net revenue:	'	'	'	'
Products and license	$18,178	$14,677	$48,003	$40,773
Services	16,924	11,667	47,023	31,643
Total net revenue	35,102	26,344	95,026	72,416
Cost of revenue:	'	'	'	'
Products and license	1,894	2,064	6,216	6,192
Services	5,396	3,466	14,909	9,338
Total cost of revenue	7,290	5,530	21,125	15,530
Gross profit	27,812	20,814	73,901	56,886
Operating expenses:	'	'	'	'
Research and development	6,725	5,154	19,729	15,072
Sales and marketing	20,135	13,218	55,963	36,740
General and administrative	4,697	4,104	13,677	11,336
Total operating expenses	31,557	22,476	89,369	63,148
Loss from operations	-3,745	-1,662	-15,468	-6,262
Other income (expense), net	113	-67	11	-126
Loss before provision for income taxes	-3,632	-1,729	-15,457	-6,388
Provision for income taxes	288	262	703	642
Net loss	-3,920	-1,991	-16,160	-7,030
Loss attributable to noncontrolling interest	145	132	411	367
Net loss attributable to Imperva, Inc. stockholders	($3,775)	($1,859)	($15,749)	($6,663)
Net loss per share of common stock attributable to Imperva, Inc. stockholders, basic and diluted	($0.15)	($0.08)	($0.65)	($0.29)
Shares used in computing net loss per share of common stock, basic and diluted	24,453	23,160	24,174	22,684

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]	'	'	'	'
Net loss	($3,920)	($1,991)	($16,160)	($7,030)
Other comprehensive loss (net of tax):	'	'	'	'
Net change in net unrealized gain (loss) on investments	25	151	-183	186
Net change in unrealized gain (loss) on hedging instruments	-328	391	-425	462
Other comprehensive income (loss)	-303	542	-608	648
Comprehensive loss	-4,223	-1,449	-16,768	-6,382
Comprehensive loss attributable to noncontrolling interest	145	132	411	367
Comprehensive loss attributable to Imperva, Inc. stockholders	($4,078)	($1,317)	($16,357)	($6,015)

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) (USD $)	Total		Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]
In Thousands, except Share data, unless otherwise specified	Total		Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]
Beginning balance at Dec. 31, 2011	$79,568		$2	$147,085	($66,130)	($616)	($773)
Beginning balance, shares at Dec. 31, 2011	'		22,978,166	'	'	'	'
Issuance of common stock, net of repurchases	2,140		'	2,140	'	'	'
Issuance of common stock, net of repurchases, shares	'		1,059,805	'	'	'	'
Vesting of restricted stock	681		'	681	'	'	'
Stock-based compensation	3,596		'	3,596	'	'	'
Purchase (Sale) of additional ownership in Incapsula, Inc.	'		'	-174	'	'	174
Components of other comprehensive income (loss), net of tax:	'		'	'	'	'	'
Change in unrealized gain (loss) on investments	186		'	'	'	186	'
Change in unrealized gain (loss) on derivatives	462		'	'	'	462	'
Net loss	-7,030		'	'	-6,663	'	-367
Comprehensive loss	-6,382		'	'	'	'	'
Ending balance at Sep. 30, 2012	79,603		2	153,328	-72,793	32	-966
Ending balance, shares at Sep. 30, 2012	'		24,037,971	'	'	'	'
Beginning balance at Dec. 31, 2012	84,231	[1]	2	157,989	-73,517	861	-1,104
Beginning balance, shares at Dec. 31, 2012	'		24,296,076	'	'	'	'
Issuance of common stock, net of repurchases	4,674		'	4,674	'	'	'
Issuance of common stock, net of repurchases, shares	'		655,433	'	'	'	'
Vesting of restricted stock	600		'	600	'	'	'
Stock-based compensation	9,858		'	9,858	'	'	'
Exercise of warrant	'		'	'	'	'	'
Exercise of warrant, shares	580,972		7,694	'	'	'	'
Purchase (Sale) of additional ownership in Incapsula, Inc.	'		'	358	'	'	-358
Components of other comprehensive income (loss), net of tax:	'		'	'	'	'	'
Change in unrealized gain (loss) on investments	-183		'	'	'	-183	'
Change in unrealized gain (loss) on derivatives	-425		'	'	'	-425	'
Net loss	-16,160		'	'	-15,749	'	-411
Comprehensive loss	-16,768		'	'	'	'	'
Ending balance at Sep. 30, 2013	$82,595		$2	$173,479	($89,266)	$253	($1,873)
Ending balance, shares at Sep. 30, 2013	'		24,959,203	'	'	'	'

[1]	The Condensed Consolidated Balance Sheet as of December 31, 2012 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.

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:	'		'
Net loss	($16,160)		($7,030)
Adjustments to reconcile net loss to net cash provided by operating activities:	'		'
Depreciation and amortization	1,935		1,312
Stock-based compensation	9,858		3,596
Amortization of premiums/accretion of discounts on short-term investments	547		337
Changes in operating assets and liabilities:	'		'
Accounts receivable, net	-1,076		-983
Inventory	-213		129
Prepaid expenses and other assets	-654		-1,134
Accounts payable	-734		196
Accrued compensation and benefits	2,547		2,616
Accrued and other liabilities	-146		-587
Severance pay (net)	16		305
Deferred revenue	6,357		5,373
Deferred tax assets	-16		-4
Other	-12		15
Net cash provided by operating activities	2,249		4,141
CASH FLOWS FROM INVESTING ACTIVITIES:	'		'
Purchase of short-term investments	-29,825		-50,744
Proceeds from sales/maturities of short-term investments	36,241		6,928
Purchase of property and equipment	-1,753		-1,758
Purchase of other assets	'		-400
Change in restricted cash	58		96
Net cash provided by (used in) investing activities	4,721		-45,878
CASH FLOWS FROM FINANCING ACTIVITIES:	'		'
Proceeds from issuance of common stock, net of repurchases	4,674		2,140
Net cash provided by financing activities	4,674		2,140
Effect of exchange rate changes on cash and cash equivalents	-205		40
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	11,439		-39,557
CASH AND CASH EQUIVALENTS - Beginning of period	59,201	[1]	96,025
CASH AND CASH EQUIVALENTS - End of period	70,640		56,468
NONCASH INVESTING AND FINANCING ACTIVITIES:	'		'
Vesting of restricted and early exercised stock options	$600		$681

[1]	The Condensed Consolidated Balance Sheet as of December 31, 2012 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.

Basis_of_Presentation_and_Summ

Basis of Presentation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Basis of Presentation and Summary of Significant Accounting Policies	'
	1	Basis of Presentation and Summary of Significant Accounting Policies
	Business
	Imperva, Inc. (together with its subsidiaries, the “Company”) was incorporated in April 2002 in Delaware. The Company is headquartered in Redwood Shores, California and has subsidiaries located throughout the world including Israel, Asia and Europe. The Company is engaged in the development, marketing, sales, service and support of business security solutions that provide visibility and control over high value business data across critical systems within the data center.
	Basis of Presentation
	The Company has prepared the accompanying unaudited Condensed Consolidated Financial Statements in accordance with Article 10 of Regulation S-X and pursuant to the rules and regulations for Form 10-Q of the Securities and Exchange Commission (the “SEC”). Pursuant to those rules and regulations, the Company has condensed or omitted certain information and footnote disclosure it normally includes in its annual consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). In management’s opinion, the Company has made all adjustments (consisting only of normal, recurring adjustments, except as otherwise indicated) necessary to fairly present its consolidated financial position, results of operations, and cash flows. The Company’s interim period operating results do not necessarily indicate the results that may be expected for any other interim period or for the full fiscal year. These financial statements and accompanying notes should be read in conjunction with the consolidated financial statements and notes thereto in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012, which was filed with the SEC on March 15, 2013 (the “Annual Report”).
	Basis of Consolidation
	The condensed consolidated financial statements include the accounts of the Company and its wholly-owned and majority-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. For its majority-owned subsidiary, Incapsula, Inc. (“Incapsula”), the Company separately presents the non-controlling interest on its Condensed Consolidated Balance Sheets in Total Stockholders’ Equity and in its Condensed Consolidated Statements of Operations.
	Concentration of Revenue and Accounts Receivable
	For the three months ended September 30, 2013 and 2012, and the nine months ended September 30, 2012 the Company did not have any customer that represented more than 10% of the Company’s total revenue. For the nine months ended September 30, 2013, the Company had one customer that represented 10% of the Company’s total revenue. There was one customer who represented 12% of gross accounts receivable as of September 30, 2013 and there was no customer representing greater than 10% of gross accounts receivable as of December 31, 2012.
	Significant Accounting Policies
	There have been no material changes to the Company’s significant accounting policies as compared to the significant accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012.
	Recent Accounting Pronouncements
	During the first quarter of 2013, the Company adopted the accounting standard update regarding reclassifications out of accumulated other comprehensive income. This standard update requires companies to report the effect of significant reclassifications out of accumulated other comprehensive income on the respective line items in our condensed consolidated statements of operations if the amount being reclassified is required to be reclassified in its entirety to net income. See Note 9 (“Accumulated Other Comprehensive Income”) for additional details.

Incapsula

Incapsula	9 Months Ended
	Sep. 30, 2013
Noncontrolling Interest [Abstract]	'
Incapsula	'
	2	Incapsula
	On November 5, 2009, the Company entered into a license agreement for Incapsula to use certain developed technology of the Company. In lieu of any other fee or royalty under the license agreement, Incapsula issued to the Company 5,000,000 shares of its Series A Convertible Preferred Stock representing a 58% ownership interest at the date of issuance. The transaction was accounted for as a business combination. No value was assigned to the license on the acquisition date as the use of the license will stay within the control of the Company. Therefore, the Company’s historical carrying value of the developed technology immediately prior to the acquisition was used to determine the value of the purchase consideration exchanged in the transaction. As Incapsula was a newly-formed entity with no net assets on the acquisition date and the value of the license was determined to be zero, no goodwill was recorded by the Company on the acquisition.
	On March 9, 2010, the Company entered into a Series A and Series A-1 Purchase Agreement whereby Incapsula issued 6,666,666 shares of its Series A Convertible Preferred Stock to the Company in exchange for cash consideration of $3.0 million. As a result of this transaction, the Company increased its ownership interest in Incapsula to 76% at the date of issuance. The purchase of the additional ownership interest in Incapsula was treated as an equity transaction. Under the terms of the Series A and Series A-1 Purchase Agreement, the Company entered into a forward contract with Incapsula to purchase 8,750,000 shares of Incapsula’s Series A-1 Convertible Preferred Stock in exchange for $7.0 million in cash consideration if certain milestones were achieved no later than September 2011. On the transaction date, no value was assigned to the forward contract as the option did not meet the definition of a derivative instrument as it did not contain a net settlement feature. Specifically, the forward contract could only be gross physically settled as Incapsula is a non-publicly traded company whose stock was not readily convertible to cash.
	In July 2011, Incapsula achieved the respective performance milestones. As a result, the Company purchased 4,375,000 shares of Incapsula’s Series A-1 Preferred Stock for $3.5 million thereby increasing its ownership interest to 82%. In January 2012, the Company purchased the remaining 4,375,000 shares of Incapsula’s Series A-1 Preferred Stock for $3.5 million thereby increasing its ownership interest in Incapsula to 85%.
	Under the terms of the agreements between the Company and Incapsula, the Company has the right, but not the obligation, to purchase the remaining ownership interest in Incapsula commencing on November 5, 2013 and ending on November 5, 2018 (the “Purchase Right”). Exercise of the Purchase Right is solely within the Company’s control and the price for the remaining ownership interest will be based on an Incapsula enterprise valuation calculated as the greater of (i) eight times Incapsula’s prior 12 months trailing revenues or (ii) seven times the aggregate amount Incapsula has raised in connection with its Series A Convertible Preferred Stock financings. On the acquisition date, no value was assigned to this Purchase Right as the option does not meet the definition of a derivative instrument as it does not contain a net settlement feature. Specifically, the Purchase Right can only be gross physically settled as Incapsula is a non-publicly traded company whose stock is not readily convertible to cash.
	As of September 30, 2013 and December 31, 2012, all of the outstanding shares of Incapsula’s Series A and A-1 Convertible Preferred Stock are held by the Company.
	In March 2010, the board of directors of Incapsula adopted the Incapsula 2010 Share Incentive Plan pursuant to which Incapsula may grant to its employees options to purchase shares of Incapsula’s common stock or restricted shares. Based on the exercise of options under this Plan during 2013, the Company’s ownership interest in Incapsula was reduced to 81% as of September 30, 2013. If the Company exercises the Purchase Right option discussed above, awards under the Incapsula 2010 Share Incentive Plan would be assumed by the Company, substituted with Company stock options or cashed out, and all outstanding awards and the Incapsula 2010 Share Plan would terminate.

Cash_Cash_Equivalents_and_Shor

Cash, Cash Equivalents, and Short-Term Investments	9 Months Ended
Cash, Cash Equivalents, and Short-Term Investments	Sep. 30, 2013
Cash And Cash Equivalents [Abstract]	'
Cash, Cash Equivalents, and Short-Term Investments	'
	3	Cash, Cash Equivalents, and Short-Term Investments
	The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. Cash and cash equivalents consist of cash on hand, highly liquid investments in commercial paper, money market funds and various deposit accounts.

	The Company considers all high quality investments purchased with original maturities at the date of purchase greater than three months to be short-term investments. Investments are available to be used for current operations and are, therefore, classified as current assets even though maturities may extend beyond one year. Cash equivalents and short-term investments are classified as available-for-sale and are, therefore, recorded at fair value on the condensed consolidated balance sheets, with any unrealized gains and losses reported in accumulated other comprehensive income (loss), which is reflected as a separate component of stockholders’ equity in its condensed consolidated balance sheets, until realized. The Company uses the specific-identification method to compute gains and losses on the investments. The amortized cost of securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion is included as a component of other income (expense), net in the condensed consolidated statements of operations.
	Cash, cash equivalents and short-term investments consist of the following (in thousands):


			As of September 30, 2013
			Amortized			Gross		Gross		Fair
			Cost			Unrealized		Unrealized		Value
						Gains		Losses
	Cash and cash equivalents:
	Cash		$	33,200		$	—	$	—	$	33,200
	Commercial paper			24,099			—		2		24,097
	Bank deposits			10,710			—		—		10,710
	Money market funds			2,633			—		—		2,633

	Total		$	70,642		$	—	$	2	$	70,640


	Short-term investments:
	Corporate debt obligations		$	26,035		$	9	$	12	$	26,032
	Bank deposits			10,153			—		—		10,153

	Total		$	36,188		$	9	$	12	$	36,185



			As of December 31, 2012
			Amortized			Gross		Gross		Fair
			Cost			Unrealized		Unrealized		Value
						Gains		Losses
	Cash and cash equivalents:
	Cash		$	27,602		$	—	$	—	$	27,602
	Commercial paper			17,748			—		3		17,745
	Corporate debt obligations			702			—		—		702
	Bank deposits			10,107			—		—		10,107
	Money market funds			3,045			—		—		3,045

	Total		$	59,204		$	—	$	3	$	59,201


	Short-term investments:
	Commercial paper		$	1,000		$	—	$	—	$	1,000
	Corporate debt obligations			29,040			22		—		29,062
	Bank deposits			10,057			—		—		10,057
	US agency securities			1,001			—		—		1,001
	Mutual funds			1,847			159		—		2,006

	Total		$	42,945		$	181	$	—	$	43,126


	None of the Company’s short-term investments have been in an unrealized loss position for more than twelve months as of September 30, 2013 and December 31, 2012.
	The following table summarizes the cost and estimated fair value of short-term investments based on stated effective maturities as of September 30, 2013 (in thousands):


			As of September 30, 2013
			Amortized			Estimated
			Cost			Fair
						Value
	Short-term investments:
	Due within one year		$	17,468		$	17,477
	Due within two years			18,720			18,708

Total		$	36,188		$	36,185

The Company reviews its short-term investments on a regular basis to evaluate whether or not any security has experienced an other-than-temporary decline in fair value. The Company considers factors such as the length of time and extent to which the market value has been less than the cost, the financial condition and near-term prospects of the issuer and its intent to sell, or whether it is more likely than not the Company will be required to sell, the investment before recovery of the investment’s amortized cost basis. If the Company believes that an other-than-temporary decline exists in one of these securities, the Company writes down these investments to fair value. For debt securities, the portion of the write-down related to credit loss would be recorded to other income (expense), net, in the Company’s condensed consolidated statements of operations. Any portion not related to credit loss would be recorded to accumulated other comprehensive income (loss), which is reflected as a separate component of stockholders’ equity in the Company’s condensed consolidated balance sheets. During the nine months ended September 30, 2013, the Company did not consider any of its investments to be other-than-temporarily impaired.

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	9 Months Ended
Fair Value of Financial Instruments	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value of Financial Instruments	'
	4. Fair Value of Financial Instruments
	The Company evaluates assets and liabilities subject to fair value measurements on a recurring basis to determine the appropriate level to classify them for each reporting period. There have been no transfers between fair value measurement levels during the nine months ended September 30, 2013.
	The Company’s cash equivalents and short-term investment instruments are classified within Level 1 or Level 2 of the fair value hierarchy because they are valued using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. The types of instruments valued based on quoted market prices in active markets include mutual funds and money market securities, and are generally classified within Level 1 of the fair value hierarchy.
	The types of instruments that are valued based on other observable inputs include investment-grade corporate bonds, commercial paper, bank deposits and United States government agency securities. Such instruments are generally classified within Level 2 of the fair value hierarchy.
	The Company executes its foreign currency contracts primarily in the retail market in an over-the-counter environment with a relatively high level of price transparency. The market participants usually are large multi-national and regional banks. The Company’s foreign currency contracts valuation inputs are based on quoted prices and quoted pricing intervals from public data sources and do not involve management judgment. These contracts are typically classified within Level 2 of the fair value hierarchy.

	The following table sets forth the Company’s assets and liabilities that were measured at fair value as of September 30, 2013 and December 31, 2012, by level within the fair value hierarchy (in thousands):


		As of September 30, 2013
		Level I		Level II		Level III		Fair Value
	Financial Assets:
	Cash and cash equivalents:
	Commercial paper	$	—	$	24,097	$	—	$	24,097
	Bank deposits		—		10,710		—		10,710
	Money market funds		2,633		—		—		2,633
	Short-term investments:
	Corporate debt obligations		—		26,032		—		26,032
	Bank deposits		—		10,153		—		10,153

	Total financial assets	$	2,633	$	70,992	$	—	$	73,625


	Prepaid expenses and other current assets - Forward foreign exchange contracts	$	—	$	745	$	—	$	745



		As of December 31, 2012
		Level I		Level II		Level III		Fair Value
	Financial Assets:
	Cash and cash equivalents:
	Commercial paper	$	—	$	17,745	$	—	$	17,745
	Corporate debt obligations		—		702		—		702
	Bank deposits		—		10,107		—		10,107
	Money market funds		3,045		—		—		3,045
	Short-term investments:
	Commercial paper		—		1,000		—		1,000
	Corporate debt obligations		—		29,062		—		29,062
	Bank deposits		—		10,057		—		10,057
	US agency securities		—		1,001		—		1,001
	Mutual funds		2,006		—		—		2,006

	Total financial assets	$	5,051	$	69,674	$	—	$	74,725


	Prepaid expenses and other current assets - Forward foreign exchange contracts	$	—	$	1,226	$	—	$	1,226

	In addition to the amounts disclosed in the above table, the fair value of the Company’s Israeli severance pay assets, which were comprised of Level II assets, was $3.7 million and $3.2 million as of September 30, 2013 and December 31, 2012, respectively.

Derivative_Instruments

Derivative Instruments	9 Months Ended
Derivative Instruments	Sep. 30, 2013
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Derivative Instruments	'
	5	Derivative Instruments
	The Company’s primary objective for holding derivative instruments is to reduce its exposure to foreign currency rate changes. The Company reduces its exposure by entering into forward foreign exchange contracts with respect to operating expenses that are forecast to be incurred in currencies other than U.S. dollars. Substantially all of the Company’s revenue and capital purchasing activities and a majority of its operating expenditures are transacted in U.S. dollars. However, certain operating expenditures are incurred in or exposed to other currencies, primarily the Israeli shekel and the Euro.
	The Company has established forecasted transaction currency risk management programs to protect against fluctuations in fair value and the volatility of future cash flows caused by changes in exchange rates. The Company’s currency risk management program includes forward foreign exchange contracts designated as cash flow hedges. These forward foreign exchange contracts generally mature within 12 months. The Company does not enter into derivative financial instruments for trading purposes.

	Derivative instruments measured at fair value and their classification on the condensed consolidated balance sheets are presented in the following tables (in thousands):


			Asset as of September 30, 2013						Asset as of December 31, 2012
			Notional			Fair Value			Notional			Fair Value
			Amount			Fair Value			Amount			Fair Value

	Foreign Exchange Forward Contract Derivatives in cash flow hedging relationships - included in prepaid expenses and other current assets		$	5,076		$	692		$	20,513		$	1,117

	Foreign Exchange Forward Contract Derivatives not designated as hedging relationships - included in prepaid expenses and other current assets		$	677		$	53		$	2,296		$	109
	Gains (losses) on derivative instruments and their classification on the condensed consolidated statement of operations are presented in the following table (in thousands):


			Three months ended						Nine months ended
			September 30,						September 30,
			2013			2012			2013			2012
	Foreign Exchange Forward Contract Derivatives in cash flow hedging relationships:
	Gains recognized in OCI (a)		$	240		$	223		$	726		$	223
	Losses recognized in OCI (a)			(7	)		(115	)		(7	)		(225	)
	Gains reclassified from accumulated OCI into net loss (b)			561			—			1,144			—
	Losses reclassified from accumulated OCI into net loss (b)			—			(283	)		—			(464	)
	Losses recognized in net loss (c)			—			—			—			(5	)

	Foreign Exchange Forward Contract Derivatives not designated as hedging relationships:
	Gains recognized in net loss (d)		$	40		$	47		$	25		$	117
	Losses recognized in net loss (d)			—			—			(15	)		(17	)

	(a)	Net change in the fair value of the effective portion classified in other comprehensive income (loss) (“OCI”).
	(b)	Effective portion of cash flow hedges reclassified from accumulated other comprehensive income (loss) into net loss, of which $36 and $525 were recognized within cost of sales and operating expenses, respectively, for the three months ended September 30, 2013 and $75 and $1,069 were recognized within cost of sales and operating expenses, respectively, for the nine months ended September 30, 2013. $(17) and $(266) were recognized within cost of sales and operating expenses, respectively for the three months ended September 30, 2012 and $(31) and $(433) were recognized within cost of sales and operating expenses, respectively, for the nine months ended September 30, 2012. All amounts are reflected within the respective condensed consolidated statement of operations.
	(c)	Ineffective portion and amount excluded from effectiveness testing classified in other income (expense), net.
	(d)	Classified in other income (expense), net.

Revolving_Credit_Facility

Revolving Credit Facility	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Revolving Credit Facility	'
	6	Revolving Credit Facility
	In September 2010, the Company entered into a revolving credit facility with a financial institution. The agreement, as amended, provides for a maximum borrowing capacity of up to $6.0 million as of September 30, 2013. As of September 30, 2013 and December 31, 2012, there was no balance outstanding on the credit facility.
	The credit facility expires on May 1, 2014, is secured by the assets of the Company, and contains a restrictive covenant that requires the Company to maintain a minimum cash and cash equivalents balance of $3.0 million. The terms of this agreement requires payment of an unused line fee of 0.25% per quarter of the unused portion and bears interest at LIBOR plus 2.75%. As of September 30, 2013 and December 31, 2012, the Company was compliant with the amended covenant of the credit facility.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2013
Commitments And Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	7	Commitments and Contingencies
	(a) Operating Leases
	The Company rents its facilities under operating leases with lease periods expiring from 2015 to 2018. Future minimum payments under these facility operating leases and minimum rentals to be received under non-cancellable subleases are as follows as of September 30, 2013 (in thousands):


	Year Ending December 31:		Operating		Estimated
			Leases		Sublease
					Income
	2013 (remaining 3 months)		$	1,047	$	181
	2014			4,621		578
	2015			2,323		240
	2016			2,357		80
	2017			1,615		0
	Thereafter			279		0

	Total		$	12,242	$	1,079

	Rent expense for the Company’s operating leases is recognized on a straight-line basis over the lease term. Rent expense for the nine months ended September 30, 2013 and 2012 was $2.5 million and $1.5 million, respectively.
	In connection with a lease of office space, the Company received tenant improvement allowances of $336,000 and $639,000 during the years ended December 31, 2012 and 2010, respectively, from the lessor for certain improvements made to the leased property. The Company has recorded the tenant improvement allowances as a leasehold improvement within property and equipment, net, and as deferred rent within other liabilities on the condensed consolidated balance sheets. The deferred rent liability is amortized to rent expense over the term of the lease on a straight-line basis. The leasehold improvements are being amortized to expense over the period from when the improvements were placed into service until the end of their useful life, which is the end of the lease term.
	In addition, certain of the Company’s operating lease agreements for office space also include rent holidays and scheduled rent escalations during the initial lease term. The Company has recorded the rent holidays as a deferred rent within other liabilities on the condensed consolidated balance sheets. The Company recognizes the deferred rent liability and scheduled rent increase on a straight-line basis into rent expense over the lease term commencing on the date the Company takes possession of the lease space.
	As of September 30, 2013 the Company has $1.3 million in restricted deposits to secure bank guarantees provided to the lessor.
	(b) Cancelable Lease Agreement
	The Company leases motor vehicles under a cancelable operating lease agreement. The Company has an option to cancel the lease agreement, which may result in penalties in a maximum amount of $85,000 as of September 30, 2013. Motor vehicle lease expenses for the nine months ended September 30, 2013 and 2012 were $1.8 million and $1.5 million, respectively.

	(c) Purchase Commitments
	As of September 30, 2013 and December 31, 2012, the Company had purchase commitments of $4.6 million and $3.2 million, respectively, to purchase inventory, trial units, and research and development equipment from its vendors. The purchase commitments result from the Company’s contractual obligation to order or build inventory in advance of anticipated sales. According to the Company’s agreements with its vendors, the Company committed to purchase inventory within nine months from the date the inventory arrived at the vendor’s warehouse.
	(d) Litigation
	From time to time, the Company may be subject to legal proceedings and claims in the ordinary course of business. The Company is not currently a party to any material litigation; however, the Company has received, and may in the future continue to receive, claims from third parties asserting, among other things, infringement of intellectual property rights. While the outcome of these matters is remote, the Company does not expect that the ultimate costs to resolve these matters will have a material effect on its consolidated financial position, results of operations or cash flows. The Company will record a liability when it believes that it is both probable that a loss has been incurred and the amount can be reasonably estimated.
	(e) Indemnification
	Under the indemnification provisions of its standard sales contracts, the Company agrees to defend its channel partners and end customers against third-party claims asserting infringement of certain intellectual property rights, which may include patents, copyrights, trademarks, or trade secrets, and to pay judgments and settlements entered on such claims. The Company’s exposure under these indemnifications provisions is generally limited to the total amount paid under the agreement. However, certain agreements included indemnification provisions that could potentially expose the Company to losses in excess of the amount received under the agreement. To date, there have been no claims under such indemnification provisions. Accordingly, the Company has not recorded a liability on its consolidated balance sheets for these indemnification provisions.
	In addition to the foregoing, the Company maintains director and officer insurance, which may cover certain liabilities arising from its obligation to indemnify its directors and officers.

Stock_Plans

Stock Plans	9 Months Ended
Stock Plans	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock Plans	'
	8	Stock Plans
	(a) 2003 Stock Plan
	During 2003, the Board of Directors adopted the 2003 Stock Plan (the “2003 Plan”), which allows for the granting of both incentive stock options and non-qualified stock options and the direct award or sale of shares of the Company’s common stock (including restricted common stock) to officers, employees, directors, consultants and other key persons. Incentive stock options may be granted to employees with exercise prices of no less than the fair value of the common stock on the grant date, and non-qualified options may be granted to employees, directors, or consultants at exercise prices of no less than 85% of the fair value of the common stock on the grant date, as determined by the Board of Directors. If, at the time the Company grants an option, the optionee directly or by attribution owns stock possessing more than 10% of the total combined voting power of all classes of stock of the Company, the option price shall be at least 110% of the fair value. Options granted under the Plan generally expire no later than ten years and, in general, vest four years from the date of grant.
	(b) 2011 Stock Option and Incentive Plan
	In September 2011, the Board of Directors adopted the 2011 Stock Option and Incentive Plan (the “2011 Plan”) which was subsequently approved by the Company’s stockholders. The 2011 Plan replaces the 2003 Plan as the Board has decided not to grant any additional awards under that plan. The Company has reserved a total of 1,000,000 shares of common stock for issuance under the 2011 Plan. In addition, any reserved but unissued shares under the 2003 Stock Plan will be added to the number of shares reserved for issuance under the 2011 Plan. The 2011 Plan also provides that the number of shares reserved and available for issuance under the plan will automatically increase each January 1, beginning in 2012 and ending in 2015, by 4% of the outstanding number of shares of common stock on the immediately preceding December 31. The Board of Directors or compensation committee may reduce the amount of the increase in any particular year. As of December 31, 2012, there were 1,967,336 shares available for grant under the 2011 Plan. On January 1, 2013, the share reserve under the 2011 Plan was automatically increased by 971,843 shares.

	The 2011 Plan permits the granting of incentive stock options, non-qualified stock options, restricted stock units (RSUs), stock appreciation rights, restricted shares of common stock and performance share awards. The exercise price of stock options may not be less than the 100% of the fair market value of the common stock on the date of grant. Options granted pursuant to the 2011 Plan generally expire in no later than ten years. The Company began granting RSUs in February 2012, which generally vest over either a four-year period with 25% vesting at the end of one year and the remainder vesting quarterly thereafter or they completely vest at the end of a three-year period.
	(c) 2011 Employee Stock Purchase Plan
	In September 2011, the Board of Directors adopted the 2011 Employee Stock Purchase Plan (the “ESPP”) which was subsequently approved by the Company’s stockholders. The ESPP took effect on the effective date of the registration statement for the Company’s IPO. The ESPP permits eligible employees to acquire shares of the Company’s common stock by accumulating funds through periodic payroll deductions of up to 15% of base salary. Each offering period may run for no more than 24 months and consist of no more than five purchase periods. The purchase price for shares of the Company’s common stock purchased under the ESPP will be 85% of the lesser of the fair market value of the Company’s common stock on the first day of the offering period or the last trading day of the applicable purchase period within that offering period.
	The Company has initially reserved a total of 500,000 shares of common stock for future issuance under the ESPP. The number of shares reserved for issuance under the ESPP will increase automatically on January 1 of each of the first eight years commencing in 2012 by the number of shares equal to 1% of the Company’s total outstanding shares as of the immediately preceding December 31. The Board of Directors or compensation committee may reduce the amount of the increase in any particular year. No more than 20,000,000 shares of common stock may be issued under the ESPP and no other shares may be added to the ESPP without the approval of the Company’s stockholders. On January 1, 2013, the share reserve under the 2011 Employee Stock Purchase Plan was automatically increased by 242,961 shares.
	(d) Incapsula 2010 Share Incentive Plan
	In March 2010, Incapsula’s board of directors adopted the Incapsula 2010 Share Incentive Plan (the “Incapsula Plan”), pursuant to which Incapsula may grant to its employees and service providers options to purchase shares of its common stock, restricted shares, or restricted share units. The total number of shares of common stock that may be granted under the Incapsula Plan shall not exceed 4,733,333 in the aggregate, subject to certain adjustments.
	The following table summarizes option activity under the Incapsula Plan and related information for the nine months ended September 30, 2013:


			Shares				Number of				Weighted
			Available for				Stock				Average
			Grant				Options				Exercise Price
							Outstanding
	Outstanding - January 1, 2013			2,753,708				1,836,500			$	0.1
	Granted			(397,500	)			397,500				0.4
	Exercised			—				(1,123,750	)			0.02
	Forfeited			129,375				(129,375	)			0.22

	Outstanding - September 30, 2013			2,485,583				980,875			$	0.3


	(e) Stock Compensation Expense
	The Company recognized stock-based compensation expense under the 2011 Stock Option and Incentive Plan, 2003 Stock Plan, 2011 Employee Stock Purchase Plan, and the Incapsula 2010 Share Incentive Plan in the condensed consolidated statements of operations as follows (in thousands):


			Three months ended								Nine months ended
			September 30,								September 30,
			2013				2012				2013				2012
	Cost of revenues		$	254			$	143			$	722			$	302
	Research and development			747				372				2,133				759
	Sales and marketing			1,620				665				4,596				1,365
	General and administrative			792				582				2,407				1,170

	Total stock-based compensation expense		$	3,413			$	1,762			$	9,858			$	3,596

	The fair value of stock option grants for the three months and nine months ended September 30, 2013 and 2012 was estimated using the following weighted average assumptions:


			Three months ended								Nine months ended
			September 30,								September 30,
			2013				2012				2013				2012
	Stock option grants:
	Dividend rate			0	%			0	%			0	%			0	%
	Risk-free interest rate			1.8	%			0.8	%			1.2	%			1	%
	Expected term (in years)			6.1				6.1				6.1				6
	Expected volatility			47	%			46	%			46	%			48	%

	ESPP grants:
	Dividend rate			—				—				0	%			0	%
	Risk-free interest rate			—				—				0.1	%			0.2	%
	Expected term (in years)			—				—				0.5				0.5
	Expected volatility			—				—				31	%			38	%
	The fair value of the RSUs is determined using the closing price of the Company’s common stock on the date of the grant. Compensation is recognized on a straight-line basis over the requisite service period of each grant adjusted for estimated forfeitures.
	The following table summarizes option activity under the 2003 Plan and the 2011 Plan and related information:


			Options Outstanding
		Number of				Weighted				Weighted				Aggregate
		Shares				Average				Average				Intrinsic Value
						Exercise Price				Remaining				(in thousands)
										Contractual
										Life (in years)
Balances - January 1, 2013			1,989,237			$	14.08				8.09			$	35,513
Granted			598,283				36.25
Exercised or released			(580,972	)			6.15
Cancelled or forfeited			(180,017	)			23.22

Balances - September 30, 2013			1,826,531			$	22.96				8.21				35,052

Options exercisable			477,469			$	11.9				6.97				14,380


RSU Activity
A summary of RSU activity under the 2003 Plan and the 2011 Plan for the nine months ended September 30, 2013, is as follows:


		Number of				Weighted-
		Restricted Stock				Average Grant
		Units				Date Fair
		Outstanding				Value
Unvested - January 1, 2013			446,915			$	31.2
Granted			539,589				36.56
Released			(27,536	)			34.13
Cancelled or expired			(60,849	)			33.53

Unvested - September 30, 2013			898,119			$	34.3

The aggregate intrinsic value of options exercised under the Plan was $20.0 million for the nine months ended September 30, 2013. The aggregate intrinsic value is calculated as the difference between the per-share exercise price and the market value of the Company’s common stock for each share subject to an option multiplied by the number of shares subject to options. As reported in the Wall Street Journal, the market value as of September 30, 2013 was $42.02 per share. As of September 30, 2013, total compensation cost related to unvested stock-based awards granted to employees under the Plan, but not yet recognized, was $29.8 million, net of estimated forfeitures. As of September 30, 2013, this cost will be amortized to expense over a weighted-average remaining period of 2.6 years, and will be adjusted for subsequent changes in estimated forfeitures. Future stock-based award grants will increase the amount of compensation expense to be recorded in these periods.
There was no capitalized stock-based compensation cost tax benefits during the nine months ended September 30, 2013 and 2012.
(f) Common Stock Subject to Repurchase
Pursuant to restricted stock agreements with the Company’s CEO, the Company has the right, but not the obligation, to repurchase the unvested shares of common stock upon termination of employment at the original purchase price per share. The repurchase rights with respect to the common stock lapse over the vesting period, which ranges from 48 months to 60 months. The amounts received in exchange for these shares have been included in other liabilities in the accompanying condensed consolidated balance sheet and are reclassified to equity as the shares vest. The Company granted 843,819 shares of restricted common stock with a weighted-average grant date fair value per share of $1.94 during the year ended December 31, 2010. There were no grants of shares of restricted common stock during the nine months ended September 30, 2013 and the years ended December 31, 2012 and 2011. As of September 30, 2013, 329,616 shares of restricted common stock held by the Company’s CEO were unvested and subject to repurchase by the Company.
(g) Early Exercise of Stock Options
In 2010 and 2011, the Company’s board of directors allowed for the early exercise of stock options granted to certain members of the Company’s board of directors. The amounts received in exchange for these shares have been included in other liabilities in the accompanying condensed consolidated balance sheet and are reclassified to equity as the shares vest. As of September 30, 2013, 54,375 shares were unvested.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	9 Months Ended
Accumulated Other Comprehensive Income	Sep. 30, 2013
Equity [Abstract]	'
Accumulated Other Comprehensive Income	'
	9	Accumulated Other Comprehensive Income
	The changes in the balances of accumulated other comprehensive income by component are as follows (in thousands):


			For the three months ended												For the three months ended
			September 30, 2013												September 30, 2012
			Unrealized				Unrealized				Total				Unrealized				Unrealized				Total
			gain (loss) on				gain (loss) on								gain (loss) on				gain (loss) on
			cash flow				investments								cash flow				investments
			hedges												hedges
	Balance at July 1		$	593			$	(37	)		$	556			$	(488	)		$	(22	)		$	(510	)
	Other comprehensive income (loss) before reclassifications			233				69				302				108				123				231
	Amounts reclassified to net loss			(561	)			(44	)			(605	)			283				28				311

	Change in other comprehensive income (loss)			(328	)			25				(303	)			391				151				542

	Balance at September 30		$	265			$	(12	)		$	253			$	(97	)		$	129			$	32



			For the nine months ended												For the nine months ended
			September 30, 2013												September 30, 2012
			Unrealized				Unrealized				Total				Unrealized				Unrealized				Total
			gain (loss) on				gain (loss) on								gain (loss) on				gain (loss) on
			cash flow				investments								cash flow				investments
			hedges												hedges
	Balance at January 1		$	690			$	171			$	861			$	(559	)		$	(57	)		$	(616	)
	Other comprehensive income (loss) before reclassifications			719				23				742				(2	)			133				131
	Amounts reclassified to net loss			(1,144	)			(206	)			(1,350	)			464				53				517

	Change in other comprehensive income (loss)			(425	)			(183	)			(608	)			462				186				648

	Balance at September 30		$	265			$	(12	)		$	253			$	(97	)		$	129			$	32


	The following is a summary of reclassifications out of accumulated other comprehensive income (loss) for the three and nine months ended September 30, 2013 and 2012 (in thousands):


			For the three months ended												For the three months ended
			September 30, 2013												September 30, 2012
			Pre-Tax				Tax				After-Tax				Pre-Tax				Tax				After-Tax
			Amount				Expense				Amount				Amount				Expense				Amount
							(Benefit)												(Benefit)
	Unrealized gains (losses) on cash flow hedges:
	Current period unrealized gain (loss)		$	233			$	—			$	233			$	108			$	—			$	108
	Reclassification adjustments 1			(561	)			—				(561	)			283				—				283

	Unrealized gains (losses) on cash flow hedges, net			(328	)			—				(328	)			391				—				391

	Unrealized gains (losses) on investments:
	Current period unrealized gain (loss)			69				—				69				123				—				123
	Reclassification adjustments 2			(44	)			—				(44	)			28				—				28

	Unrealized gains (losses) on investments:			25				—				25				151				—				151

	Other comprehensive income/(loss)		$	(303	)		$	—			$	(303	)		$	542			$	—			$	542



			For the nine months ended												For the nine months ended
			September 30, 2013												September 30, 2012
			Pre-Tax				Tax				After-Tax				Pre-Tax				Tax				After-Tax
			Amount				Expense				Amount				Amount				Expense				Amount
			(Benefit)												(Benefit)
Unrealized gains (losses) on cash flow hedges:
Current period unrealized gain (loss)		$	719			$	—			$	719			$	(2	)		$	—			$	(2	)
Reclassification adjustments 1			(1,144	)			—				(1,144	)			464				—				464

Unrealized gains (losses) on cash flow hedges, net			(425	)			—				(425	)			462				—				462

Unrealized gains (losses) on investments:
Current period unrealized gain (loss)			23				—				23				133				—				133
Reclassification adjustments 2			(206	)			—				(206	)			53				—				53

Unrealized gains (losses) on investments:			(183	)			—				(183	)			186				—				186

Other comprehensive income/(loss)		$	(608	)		$	—			$	(608	)		$	648			$	—			$	648


1	Refer to note 5 for the affected line items in the condensed consolidated statement of operations
2	Amount included in other income (expense), net, in the condensed consolidated statement of operations

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	10	Income Taxes
	The Company is subject to income tax in the United States as well as other tax jurisdictions in which it conducts business. Earnings from non-U.S. activities are subject to local country income tax. The Company does not provide for federal income taxes on the undistributed earnings of its foreign subsidiaries as such earnings are to be reinvested indefinitely. The Company recorded income tax expense of $0.3 million and $0.3 million for the three months ended September 30, 2013 and 2012, respectively and $0.7 million and $0.6 million for the nine months ended September 30, 2013 and 2012, respectively. These income tax expense amounts were primarily attributable to foreign taxes.
	Factors that impact the income tax provision include, but are not limited to, stock-based compensation expense, permanent tax adjustments, foreign operations and a valuation allowance against the Company’s deferred tax assets.

Segment_Information

Segment Information	9 Months Ended
Segment Information	Sep. 30, 2013
Segment Reporting [Abstract]	'
Segment Information	'
	11	Segment Information
	The Company has two operating segments which are also both reportable business segments: (i) Imperva, which is comprised of Imperva’s and its wholly-owned subsidiaries’ financial position and results of operations; and (ii) Incapsula, which is comprised entirely of the financial position and results from operations of the Company’s majority-owned subsidiary, which commenced operations in late 2009.

	The following table presents a summary of the Company’s operating segments (in thousands):


			For the three months ended						For the nine months ended
			September 30,						September 30,
			2013			2012			2013			2012
	Imperva:
	Net revenue		$	34,259		$	26,122		$	93,147		$	71,941
	Operating loss			(2,848	)		(957	)		(12,718	)		(4,238	)
	Provision for income tax			263			224			674			597
	Net loss			(3,022	)		(1,134	)		(13,552	)		(4,783	)
	Depreciation and amortization			576			427			1,682			1,237
	Stock-based compensation			3,387			1,755			9,816			3,575
	Total assets		$	158,158		$	136,401		$	158,158		$	136,401

	Incapsula:
	Net revenue		$	843		$	222		$	1,879		$	475
	Operating loss			(897	)		(705	)		(2,750	)		(2,024	)
	Provision for income tax			25			38			29			45
	Net loss			(898	)		(857	)		(2,608	)		(2,247	)
	Depreciation and amortization			89			35			253			75
	Stock-based compensation			26			7			42			21
	Total assets		$	2,140		$	4,378		$	2,140		$	4,378
	The Company’s net services revenue is comprised of the following (in thousands):


			For the three months ended						For the nine months ended
			September 30,						September 30,
			2013			2012			2013			2012
	Maintenance and support		$	11,139		$	8,582		$	31,926		$	24,072
	Professional services and training			2,724			1,749			7,495			4,589
	Subscriptions			3,061			1,336			7,602			2,982

	Total net services revenue		$	16,924		$	11,667		$	47,023		$	31,643

	The Company’s net revenue by geographic region, based on the customer’s location, is summarized as follows (in thousands):


			For the three months ended						For the nine months ended
			September 30,						September 30,
			2013			2012			2013			2012
	Americas		$	19,941		$	16,226		$	58,168		$	43,341
	EMEA			9,737			5,623			22,239			16,412
	APAC			5,424			4,495			14,619			12,663

	Total net revenue		$	35,102		$	26,344		$	95,026		$	72,416


	The following table presents long-lived assets by location (in thousands):


			As of			As of
			September 30,			December 31,
			2013			2012
	United States		$	2,914		$	2,851
	Israel			2,409			2,642
	Other			10			22

	Total long-lived assets		$	5,333		$	5,515

Net_Loss_per_Share

Net Loss per Share	9 Months Ended
Net Loss per Share	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Net Loss per Share	'
	12	Net Loss per Share
	The following outstanding shares of common stock and potential common shares were excluded from the computation of diluted net loss per share of common stock for the periods presented because including them would have been antidilutive:


			For the three months and nine
			months ended September 30,
			2013		2012
	Stock options to purchase common stock			1,826,531		2,213,529
	Restricted stock units for common stock			898,119		380,393
	Restricted shares of common stock subject to repurchase			383,991		579,708
	Common stock warrants			—		8,333

Related_Party_Transaction

Related Party Transaction	9 Months Ended
	Sep. 30, 2013
Related Party Transactions [Abstract]	'
Related Party Transaction	'
	13	Related Party Transaction
	The Company indirectly sells its products, licenses and services through a third party to Seagate Technology, a President of which is also director of the Company. Net revenues recorded from indirect sales to Seagate Technology were approximately $0.3 million for the nine months ended September 30, 2012, respectively. Net revenues for the three months ended September 30, 2012 and for the three months and nine months ended September 30, 2013 were not significant. As of September 30, 2013, Imperva accounts receivable due from the reseller for the indirect sales to Seagate were not significant.

Subsequent_Event

Subsequent Event	9 Months Ended
	Sep. 30, 2013
Subsequent Events [Abstract]	'
Subsequent Event	'
	14	Subsequent Event
	In October 2013, the Company loaned $1.1 million to Incapsula, Inc. at a rate of 2% with a maturity date of December 31, 2014 (the “Incapsula Loan”). During November 2013, the Company reached an agreement in principle with the major stockholders of Incapsula (other than the Company) to acquire the remaining outstanding capital stock and assume outstanding options to acquire capital stock of Incapsula not already owned by the Company (the “Incapsula Acquisition”). The aggregate consideration for the Incapsula Acquisition is expected to be substantially on the terms of the Purchase Right less the outstanding principal and interest under the Incapsula Loan. The Company does not expect to enter into a binding definitive agreement with respect to such acquisition until February 2014, and the completion of the transaction is expected to be subject to customary closing conditions, including regulatory clearance. In connection with the agreement in principle, Imperva will issue RSUs for approximately 264,878 shares of Company common stock with performance-based vesting tied to 2014 revenue for Incapsula and Incapsula-related products and services (effectively valuing such revenues similarly to the Purchase Right) less the then-outstanding principal and interest under the Incapsula Loan, and Incapsula will issue similar RSUs for approximately 204,820 shares on an as-converted to Company common stock-basis, in addition to the consideration for the Incapsula Acquisition. These performance-based RSUs to be granted by the Company and Incapsula will be issued to continuing employees of Incapsula.

Basis_of_Presentation_and_Summ1

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Business	'
	Business
	Imperva, Inc. (together with its subsidiaries, the “Company”) was incorporated in April 2002 in Delaware. The Company is headquartered in Redwood Shores, California and has subsidiaries located throughout the world including Israel, Asia and Europe. The Company is engaged in the development, marketing, sales, service and support of business security solutions that provide visibility and control over high value business data across critical systems within the data center.
Basis of Presentation	'
	Basis of Presentation
	The Company has prepared the accompanying unaudited Condensed Consolidated Financial Statements in accordance with Article 10 of Regulation S-X and pursuant to the rules and regulations for Form 10-Q of the Securities and Exchange Commission (the “SEC”). Pursuant to those rules and regulations, the Company has condensed or omitted certain information and footnote disclosure it normally includes in its annual consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). In management’s opinion, the Company has made all adjustments (consisting only of normal, recurring adjustments, except as otherwise indicated) necessary to fairly present its consolidated financial position, results of operations, and cash flows. The Company’s interim period operating results do not necessarily indicate the results that may be expected for any other interim period or for the full fiscal year. These financial statements and accompanying notes should be read in conjunction with the consolidated financial statements and notes thereto in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012, which was filed with the SEC on March 15, 2013 (the “Annual Report”).
Basis of Consolidation	'
	Basis of Consolidation
	The condensed consolidated financial statements include the accounts of the Company and its wholly-owned and majority-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. For its majority-owned subsidiary, Incapsula, Inc. (“Incapsula”), the Company separately presents the non-controlling interest on its Condensed Consolidated Balance Sheets in Total Stockholders’ Equity and in its Condensed Consolidated Statements of Operations.
Concentration of Revenue and Accounts Receivable	'
	Concentration of Revenue and Accounts Receivable
	For the three months ended September 30, 2013 and 2012, and the nine months ended September 30, 2012 the Company did not have any customer that represented more than 10% of the Company’s total revenue. For the nine months ended September 30, 2013, the Company had one customer that represented 10% of the Company’s total revenue. There was one customer who represented 12% of gross accounts receivable as of September 30, 2013 and there was no customer representing greater than 10% of gross accounts receivable as of December 31, 2012.
Significant Accounting Policies	'
	Significant Accounting Policies
	There have been no material changes to the Company’s significant accounting policies as compared to the significant accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012.
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	During the first quarter of 2013, the Company adopted the accounting standard update regarding reclassifications out of accumulated other comprehensive income. This standard update requires companies to report the effect of significant reclassifications out of accumulated other comprehensive income on the respective line items in our condensed consolidated statements of operations if the amount being reclassified is required to be reclassified in its entirety to net income. See Note 9 (“Accumulated Other Comprehensive Income”) for additional details.

Cash_Cash_Equivalents_and_Shor1

Cash, Cash Equivalents, and Short-Term Investments (Tables)	9 Months Ended
Cash, Cash Equivalents, and Short-Term Investments (Tables)	Sep. 30, 2013
Cash And Cash Equivalents [Abstract]	'
Summary of Cash, Cash Equivalents and Short-Term Investments	'
	Cash, cash equivalents and short-term investments consist of the following (in thousands):


		As of September 30, 2013
		Amortized		Gross		Gross		Fair
		Cost		Unrealized		Unrealized		Value
				Gains		Losses
	Cash and cash equivalents:
	Cash	$	33,200	$	—	$	—	$	33,200
	Commercial paper		24,099		—		2		24,097
	Bank deposits		10,710		—		—		10,710
	Money market funds		2,633		—		—		2,633

	Total	$	70,642	$	—	$	2	$	70,640


	Short-term investments:
	Corporate debt obligations	$	26,035	$	9	$	12	$	26,032
	Bank deposits		10,153		—		—		10,153

	Total	$	36,188	$	9	$	12	$	36,185



		As of December 31, 2012
		Amortized		Gross		Gross		Fair
		Cost		Unrealized		Unrealized		Value
				Gains		Losses
	Cash and cash equivalents:
	Cash	$	27,602	$	—	$	—	$	27,602
	Commercial paper		17,748		—		3		17,745
	Corporate debt obligations		702		—		—		702
	Bank deposits		10,107		—		—		10,107
	Money market funds		3,045		—		—		3,045

	Total	$	59,204	$	—	$	3	$	59,201


	Short-term investments:
	Commercial paper	$	1,000	$	—	$	—	$	1,000
	Corporate debt obligations		29,040		22		—		29,062
	Bank deposits		10,057		—		—		10,057
	US agency securities		1,001		—		—		1,001
	Mutual funds		1,847		159		—		2,006

	Total	$	42,945	$	181	$	—	$	43,126

Summary of Cost and Estimated Fair Value of Short-Term Investments	'
	The following table summarizes the cost and estimated fair value of short-term investments based on stated effective maturities as of September 30, 2013 (in thousands):


		As of September 30, 2013
		Amortized		Estimated
		Cost		Fair
				Value
	Short-term investments:
	Due within one year	$	17,468	$	17,477
	Due within two years		18,720		18,708

	Total	$	36,188	$	36,185

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	9 Months Ended
Fair Value of Financial Instruments (Tables)	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Assets and Liabilities Subject to Fair Value Measurements on Recurring Basis	'
	The following table sets forth the Company’s assets and liabilities that were measured at fair value as of September 30, 2013 and December 31, 2012, by level within the fair value hierarchy (in thousands):


		As of September 30, 2013
		Level I		Level II		Level III		Fair Value
	Financial Assets:
	Cash and cash equivalents:
	Commercial paper	$	—	$	24,097	$	—	$	24,097
	Bank deposits		—		10,710		—		10,710
	Money market funds		2,633		—		—		2,633
	Short-term investments:
	Corporate debt obligations		—		26,032		—		26,032
	Bank deposits		—		10,153		—		10,153

	Total financial assets	$	2,633	$	70,992	$	—	$	73,625


	Prepaid expenses and other current assets - Forward foreign exchange contracts	$	—	$	745	$	—	$	745



		As of December 31, 2012
		Level I		Level II		Level III		Fair Value
	Financial Assets:
	Cash and cash equivalents:
	Commercial paper	$	—	$	17,745	$	—	$	17,745
	Corporate debt obligations		—		702		—		702
	Bank deposits		—		10,107		—		10,107
	Money market funds		3,045		—		—		3,045
	Short-term investments:
	Commercial paper		—		1,000		—		1,000
	Corporate debt obligations		—		29,062		—		29,062
	Bank deposits		—		10,057		—		10,057
	US agency securities		—		1,001		—		1,001
	Mutual funds		2,006		—		—		2,006

	Total financial assets	$	5,051	$	69,674	$	—	$	74,725


	Prepaid expenses and other current assets - Forward foreign exchange contracts	$	—	$	1,226	$	—	$	1,226

Derivative_Instruments_Tables

Derivative Instruments (Tables)	9 Months Ended
Derivative Instruments (Tables)	Sep. 30, 2013
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Derivative Instruments Measured at Fair Value	'
	Derivative instruments measured at fair value and their classification on the condensed consolidated balance sheets are presented in the following tables (in thousands):


			Asset as of September 30, 2013						Asset as of December 31, 2012
			Notional			Fair Value			Notional			Fair Value
			Amount			Fair Value			Amount			Fair Value

	Foreign Exchange Forward Contract Derivatives in cash flow hedging relationships - included in prepaid expenses and other current assets		$	5,076		$	692		$	20,513		$	1,117

	Foreign Exchange Forward Contract Derivatives not designated as hedging relationships - included in prepaid expenses and other current assets		$	677		$	53		$	2,296		$	109
Gains (Losses) on Derivative Instruments and Classification on Condensed Consolidated Statement of Operations	'
	Gains (losses) on derivative instruments and their classification on the condensed consolidated statement of operations are presented in the following table (in thousands):


			Three months ended						Nine months ended
			September 30,						September 30,
			2013			2012			2013			2012
	Foreign Exchange Forward Contract Derivatives in cash flow hedging relationships:
	Gains recognized in OCI (a)		$	240		$	223		$	726		$	223
	Losses recognized in OCI (a)			(7	)		(115	)		(7	)		(225	)
	Gains reclassified from accumulated OCI into net loss (b)			561			—			1,144			—
	Losses reclassified from accumulated OCI into net loss (b)			—			(283	)		—			(464	)
	Losses recognized in net loss (c)			—			—			—			(5	)

	Foreign Exchange Forward Contract Derivatives not designated as hedging relationships:
	Gains recognized in net loss (d)		$	40		$	47		$	25		$	117
	Losses recognized in net loss (d)			—			—			(15	)		(17	)

	(a)	Net change in the fair value of the effective portion classified in other comprehensive income (loss) (“OCI”).
	(b)	Effective portion of cash flow hedges reclassified from accumulated other comprehensive income (loss) into net loss, of which $36 and $525 were recognized within cost of sales and operating expenses, respectively, for the three months ended September 30, 2013 and $75 and $1,069 were recognized within cost of sales and operating expenses, respectively, for the nine months ended September 30, 2013. $(17) and $(266) were recognized within cost of sales and operating expenses, respectively for the three months ended September 30, 2012 and $(31) and $(433) were recognized within cost of sales and operating expenses, respectively, for the nine months ended September 30, 2012. All amounts are reflected within the respective condensed consolidated statement of operations.
	(c)	Ineffective portion and amount excluded from effectiveness testing classified in other income (expense), net.
	(d)	Classified in other income (expense), net.

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	9 Months Ended
Commitments and Contingencies (Tables)	Sep. 30, 2013
Commitments And Contingencies Disclosure [Abstract]	'
Future Minimum Payments Under Operating Leases and Minimum Rentals to be Received Under Non-Cancellable Subleases	'
	Future minimum payments under these facility operating leases and minimum rentals to be received under non-cancellable subleases are as follows as of September 30, 2013 (in thousands):


	Year Ending December 31:	Operating		Estimated
		Leases		Sublease
				Income
	2013 (remaining 3 months)	$	1,047	$	181
	2014		4,621		578
	2015		2,323		240
	2016		2,357		80
	2017		1,615		0
	Thereafter		279		0

	Total	$	12,242	$	1,079

Stock_Plans_Tables

Stock Plans (Tables)	9 Months Ended
Stock Plans (Tables)	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Option Activity Under Incapsula Plan	'
	The following table summarizes option activity under the Incapsula Plan and related information for the nine months ended September 30, 2013:


		Shares			Number of			Weighted
		Available for			Stock			Average
		Grant			Options			Exercise Price
					Outstanding
	Outstanding - January 1, 2013		2,753,708			1,836,500		$	0.1
	Granted		(397,500	)		397,500			0.4
	Exercised		—			(1,123,750	)		0.02
	Forfeited		129,375			(129,375	)		0.22

	Outstanding - September 30, 2013		2,485,583			980,875		$	0.3

Stock-Based Compensation Expense	'
	The Company recognized stock-based compensation expense under the 2011 Stock Option and Incentive Plan, 2003 Stock Plan, 2011 Employee Stock Purchase Plan, and the Incapsula 2010 Share Incentive Plan in the condensed consolidated statements of operations as follows (in thousands):


		Three months ended						Nine months ended
		September 30,						September 30,
		2013			2012			2013			2012
	Cost of revenues	$	254		$	143		$	722		$	302
	Research and development		747			372			2,133			759
	Sales and marketing		1,620			665			4,596			1,365
	General and administrative		792			582			2,407			1,170

	Total stock-based compensation expense	$	3,413		$	1,762		$	9,858		$	3,596

Weighted Average Assumptions for Fair Value of Stock Options Granted to Employees	'
	The fair value of stock option grants for the three months and nine months ended September 30, 2013 and 2012 was estimated using the following weighted average assumptions:


		Three months ended						Nine months ended
		September 30,						September 30,
		2013			2012			2013			2012
	Stock option grants:
	Dividend rate		0	%		0	%		0	%		0	%
	Risk-free interest rate		1.8	%		0.8	%		1.2	%		1	%
	Expected term (in years)		6.1			6.1			6.1			6
	Expected volatility		47	%		46	%		46	%		48	%

	ESPP grants:
	Dividend rate		—			—			0	%		0	%
	Risk-free interest rate		—			—			0.1	%		0.2	%
	Expected term (in years)		—			—			0.5			0.5
	Expected volatility		—			—			31	%		38	%
Summary of Option Activity Under 2003 Plan and 2011 Plan and Related Information	'
	The following table summarizes option activity under the 2003 Plan and the 2011 Plan and related information:


		Options Outstanding
		Number of			Weighted			Weighted			Aggregate
		Shares			Average			Average			Intrinsic Value
					Exercise Price			Remaining			(in thousands)
								Contractual
								Life (in years)
	Balances - January 1, 2013		1,989,237		$	14.08			8.09		$	35,513
	Granted		598,283			36.25
	Exercised or released		(580,972	)		6.15
	Cancelled or forfeited		(180,017	)		23.22

	Balances - September 30, 2013		1,826,531		$	22.96			8.21			35,052

	Options exercisable		477,469		$	11.9			6.97			14,380

Summary of RSU Activity Under 2003 Plan and 2011 Plan Outstanding and Weighted Average Grant Date Fair Value	'
	RSU Activity
	A summary of RSU activity under the 2003 Plan and the 2011 Plan for the nine months ended September 30, 2013, is as follows:


		Number of			Weighted-
		Restricted Stock			Average Grant
		Units			Date Fair
		Outstanding			Value
	Unvested - January 1, 2013		446,915		$	31.2
	Granted		539,589			36.56
	Released		(27,536	)		34.13
	Cancelled or expired		(60,849	)		33.53

	Unvested - September 30, 2013		898,119		$	34.3

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	9 Months Ended
Accumulated Other Comprehensive Income (Tables)	Sep. 30, 2013
Equity [Abstract]	'
Changes in Balances of Accumulated Other Comprehensive Income	'
	The changes in the balances of accumulated other comprehensive income by component are as follows (in thousands):


			For the three months ended									For the three months ended
			September 30, 2013									September 30, 2012
			Unrealized			Unrealized			Total			Unrealized			Unrealized			Total
			gain (loss) on			gain (loss) on						gain (loss) on			gain (loss) on
			cash flow			investments						cash flow			investments
			hedges									hedges
	Balance at July 1		$	593		$	(37	)	$	556		$	(488	)	$	(22	)	$	(510	)
	Other comprehensive income (loss) before reclassifications			233			69			302			108			123			231
	Amounts reclassified to net loss			(561	)		(44	)		(605	)		283			28			311

	Change in other comprehensive income (loss)			(328	)		25			(303	)		391			151			542

	Balance at September 30		$	265		$	(12	)	$	253		$	(97	)	$	129		$	32



			For the nine months ended									For the nine months ended
			September 30, 2013									September 30, 2012
			Unrealized			Unrealized			Total			Unrealized			Unrealized			Total
			gain (loss) on			gain (loss) on						gain (loss) on			gain (loss) on
			cash flow			investments						cash flow			investments
			hedges									hedges
	Balance at January 1		$	690		$	171		$	861		$	(559	)	$	(57	)	$	(616	)
	Other comprehensive income (loss) before reclassifications			719			23			742			(2	)		133			131
	Amounts reclassified to net loss			(1,144	)		(206	)		(1,350	)		464			53			517

	Change in other comprehensive income (loss)			(425	)		(183	)		(608	)		462			186			648

	Balance at September 30		$	265		$	(12	)	$	253		$	(97	)	$	129		$	32

Summary of Reclassifications Out of Accumulated Other Comprehensive Income (Loss)	'
	The following is a summary of reclassifications out of accumulated other comprehensive income (loss) for the three and nine months ended September 30, 2013 and 2012 (in thousands):


			For the three months ended									For the three months ended
			September 30, 2013									September 30, 2012
			Pre-Tax			Tax			After-Tax			Pre-Tax			Tax			After-Tax
			Amount			Expense			Amount			Amount			Expense			Amount
						(Benefit)									(Benefit)
	Unrealized gains (losses) on cash flow hedges:
	Current period unrealized gain (loss)		$	233		$	—		$	233		$	108		$	—		$	108
	Reclassification adjustments 1			(561	)		—			(561	)		283			—			283

	Unrealized gains (losses) on cash flow hedges, net			(328	)		—			(328	)		391			—			391

	Unrealized gains (losses) on investments:
	Current period unrealized gain (loss)			69			—			69			123			—			123
	Reclassification adjustments 2			(44	)		—			(44	)		28			—			28

	Unrealized gains (losses) on investments:			25			—			25			151			—			151

	Other comprehensive income/(loss)		$	(303	)	$	—		$	(303	)	$	542		$	—		$	542



			For the nine months ended									For the nine months ended
			September 30, 2013									September 30, 2012
			Pre-Tax			Tax			After-Tax			Pre-Tax			Tax			After-Tax
			Amount			Expense			Amount			Amount			Expense			Amount
						(Benefit)									(Benefit)
	Unrealized gains (losses) on cash flow hedges:
	Current period unrealized gain (loss)		$	719		$	—		$	719		$	(2	)	$	—		$	(2	)
	Reclassification adjustments 1			(1,144	)		—			(1,144	)		464			—			464

	Unrealized gains (losses) on cash flow hedges, net			(425	)		—			(425	)		462			—			462

	Unrealized gains (losses) on investments:
	Current period unrealized gain (loss)			23			—			23			133			—			133
	Reclassification adjustments 2			(206	)		—			(206	)		53			—			53

	Unrealized gains (losses) on investments:			(183	)		—			(183	)		186			—			186

	Other comprehensive income/(loss)		$	(608	)	$	—		$	(608	)	$	648		$	—		$	648


	1	Refer to note 5 for the affected line items in the condensed consolidated statement of operations
	2	Amount included in other income (expense), net, in the condensed consolidated statement of operations

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
Segment Information (Tables)	Sep. 30, 2013
Summary of Company's Operating Segments	'
	The following table presents a summary of the Company’s operating segments (in thousands):


		For the three months ended						For the nine months ended
		September 30,						September 30,
		2013			2012			2013			2012
	Imperva:
	Net revenue	$	34,259		$	26,122		$	93,147		$	71,941
	Operating loss		(2,848	)		(957	)		(12,718	)		(4,238	)
	Provision for income tax		263			224			674			597
	Net loss		(3,022	)		(1,134	)		(13,552	)		(4,783	)
	Depreciation and amortization		576			427			1,682			1,237
	Stock-based compensation		3,387			1,755			9,816			3,575
	Total assets	$	158,158		$	136,401		$	158,158		$	136,401

	Incapsula:
	Net revenue	$	843		$	222		$	1,879		$	475
	Operating loss		(897	)		(705	)		(2,750	)		(2,024	)
	Provision for income tax		25			38			29			45
	Net loss		(898	)		(857	)		(2,608	)		(2,247	)
	Depreciation and amortization		89			35			253			75
	Stock-based compensation		26			7			42			21
	Total assets	$	2,140		$	4,378		$	2,140		$	4,378
Company's Net Revenue by Geographic Region, Based on Customer's Location	'
	The Company’s net services revenue is comprised of the following (in thousands):


		For the three months ended						For the nine months ended
		September 30,						September 30,
		2013			2012			2013			2012
	Maintenance and support	$	11,139		$	8,582		$	31,926		$	24,072
	Professional services and training		2,724			1,749			7,495			4,589
	Subscriptions		3,061			1,336			7,602			2,982

	Total net services revenue	$	16,924		$	11,667		$	47,023		$	31,643

Long-Lived Assets by Location	'
	The following table presents long-lived assets by location (in thousands):


		As of			As of
		September 30,			December 31,
		2013			2012
	United States	$	2,914		$	2,851
	Israel		2,409			2,642
	Other		10			22

	Total long-lived assets	$	5,333		$	5,515

Geographic Location [Member]	'
Company's Net Revenue by Geographic Region, Based on Customer's Location	'
	The Company’s net revenue by geographic region, based on the customer’s location, is summarized as follows (in thousands):


		For the three months ended						For the nine months ended
		September 30,						September 30,
		2013			2012			2013			2012
	Americas	$	19,941		$	16,226		$	58,168		$	43,341
	EMEA		9,737			5,623			22,239			16,412
	APAC		5,424			4,495			14,619			12,663

	Total net revenue	$	35,102		$	26,344		$	95,026		$	72,416

Net_Loss_per_Share_Tables

Net Loss per Share (Tables)	9 Months Ended
Net Loss per Share (Tables)	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Antidilutive Securities Excluded from Computation of Diluted Net Loss Per Share of Common Stock	'
	The following outstanding shares of common stock and potential common shares were excluded from the computation of diluted net loss per share of common stock for the periods presented because including them would have been antidilutive:


		For the three months and nine
		months ended September 30,
		2013		2012
	Stock options to purchase common stock		1,826,531		2,213,529
	Restricted stock units for common stock		898,119		380,393
	Restricted shares of common stock subject to repurchase		383,991		579,708
	Common stock warrants		—		8,333

Basis_of_Presentation_and_Summ2

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
	Customer	Customer	Customer	Customer	Customer
Revenue Recognition, Milestone Method [Line Items]	'	'	'	'	'
Minimum percentage of revenue or gross accounts receivable required to be significant customers	10.00%	10.00%	10.00%	10.00%	'
Number of customers represented more than 10% of revenue	0	0	1	0	'
Number of customers greater than 10% of gross accounts receivable	1	'	1	'	0
Gross Accounts Receivable [Member]	'	'	'	'	'
Revenue Recognition, Milestone Method [Line Items]	'	'	'	'	'
Percentage of gross accounts receivable by major customer	'	'	12.00%	'	'

Incapsula_Additional_Informati

Incapsula - Additional Information (Detail) (USD $)	Sep. 30, 2013	Mar. 09, 2010	Nov. 05, 2009	Sep. 30, 2013	Mar. 09, 2010	Mar. 09, 2010	Sep. 30, 2013	Jan. 31, 2012	Jul. 31, 2011
		Series A Convertible Preferred Stock [Member]	Series A Convertible Preferred Stock [Member]	Series A Convertible Preferred Stock [Member]	Series A-1 Convertible Preferred Stock [Member]	Series A-1 Convertible Preferred Stock [Member]	Trailing Revenue [Member]	Series A-1 Preferred Stock [Member]	Series A-1 Preferred Stock [Member]
				Times		Forward Contracts [Member]	Times
Subsidiary or Equity Method Investee [Line Items]	'	'	'	'	'	'	'	'	'
Equity method investments, shares	'	6,666,666	5,000,000	'	8,750,000	'	'	4,375,000	4,375,000
Ownership interest	81.00%	76.00%	58.00%	'	'	'	'	85.00%	82.00%
Value assigned to license	'	'	$0	'	'	'	'	'	'
Net assets	'	'	0	'	'	'	'	'	'
Value of goodwill on the acquisition date	'	'	0	'	'	'	'	'	'
Cash consideration	'	3,000,000	'	'	7,000,000	'	'	3,500,000	3,500,000
Value assigned to forward contract	'	'	'	'	'	0	'	'	'
Enterprise valuation for computation of share price	'	'	'	7	'	'	8	'	'
Value assigned to purchase right	'	'	'	$0	'	'	'	'	'

Cash_Cash_Equivalents_and_Shor2

Cash, Cash Equivalents, and Short-Term Investments - Summary of Cash, Cash Equivalents and Short-Term Investments (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012		Sep. 30, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012		Sep. 30, 2012	Dec. 31, 2011
Schedule of Investments [Line Items]	'	'		'	'
Cash and cash equivalents, Amortized Cost	$70,642	$59,204		'	'
Cash and cash equivalents, Gross Unrealized Gains	'	'		'	'
Cash and cash equivalents, Gross Unrealized Losses	2	3		'	'
Cash and cash equivalents, Fair Value	70,640	59,201	[1]	56,468	96,025
Short-term investments, Amortized Cost	36,188	42,945		'	'
Short-term investments, Gross Unrealized Gains	9	181		'	'
Short-term investments, Gross Unrealized Losses	12	'		'	'
Short-term investments, Estimated Fair Value	36,185	43,126	[1]	'	'
Commercial paper [Member]	'	'		'	'
Schedule of Investments [Line Items]	'	'		'	'
Cash and cash equivalents, Amortized Cost	24,099	17,748		'	'
Cash and cash equivalents, Gross Unrealized Gains	'	'		'	'
Cash and cash equivalents, Gross Unrealized Losses	2	3		'	'
Cash and cash equivalents, Fair Value	24,097	17,745		'	'
Short-term investments, Amortized Cost	'	1,000		'	'
Short-term investments, Estimated Fair Value	'	1,000		'	'
Corporate debt obligations [Member]	'	'		'	'
Schedule of Investments [Line Items]	'	'		'	'
Cash and cash equivalents, Amortized Cost	'	702		'	'
Cash and cash equivalents, Fair Value	'	702		'	'
Short-term investments, Amortized Cost	26,035	29,040		'	'
Short-term investments, Gross Unrealized Gains	9	22		'	'
Short-term investments, Gross Unrealized Losses	12	'		'	'
Short-term investments, Estimated Fair Value	26,032	29,062		'	'
Bank deposits [Member]	'	'		'	'
Schedule of Investments [Line Items]	'	'		'	'
Cash and cash equivalents, Amortized Cost	10,710	10,107		'	'
Cash and cash equivalents, Gross Unrealized Gains	'	'		'	'
Cash and cash equivalents, Fair Value	10,710	10,107		'	'
Short-term investments, Amortized Cost	10,153	10,057		'	'
Short-term investments, Estimated Fair Value	10,153	10,057		'	'
US agency securities [Member]	'	'		'	'
Schedule of Investments [Line Items]	'	'		'	'
Short-term investments, Amortized Cost	'	1,001		'	'
Short-term investments, Estimated Fair Value	'	1,001		'	'
Mutual funds [Member]	'	'		'	'
Schedule of Investments [Line Items]	'	'		'	'
Short-term investments, Amortized Cost	'	1,847		'	'
Short-term investments, Gross Unrealized Gains	'	159		'	'
Short-term investments, Estimated Fair Value	'	2,006		'	'
Cash [Member]	'	'		'	'
Schedule of Investments [Line Items]	'	'		'	'
Cash and cash equivalents, Amortized Cost	33,200	27,602		'	'
Cash and cash equivalents, Gross Unrealized Gains	'	'		'	'
Cash and cash equivalents, Fair Value	33,200	27,602		'	'
Money market funds [Member]	'	'		'	'
Schedule of Investments [Line Items]	'	'		'	'
Cash and cash equivalents, Amortized Cost	2,633	3,045		'	'
Cash and cash equivalents, Gross Unrealized Gains	'	'		'	'
Cash and cash equivalents, Fair Value	$2,633	$3,045		'	'

[1]	The Condensed Consolidated Balance Sheet as of December 31, 2012 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.

Cash_Cash_Equivalents_and_Shor3

Cash, Cash Equivalents, and Short-Term Investments - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Short Term Investments [Abstract]	'	'
Short-term investments continuous unrealized loss position twelve months or longer value	$0	$0

Cash_Cash_Equivalents_and_Shor4

Cash, Cash Equivalents, and Short-Term Investments - Summary of Cost and Estimated Fair Value of Short-Term Investments (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Short Term Investments [Abstract]	'	'
Amortized Cost of short-term investments, Due within one year	$17,468	'
Amortized Cost of short-term investments, Due within two years	18,720	'
Short-term investments, Amortized Cost	36,188	42,945
Estimated fair value of short-term investments, Due within one year	17,477	'
Estimated fair value of short-term investments, Due within two years	18,708	'
Short-term investments, Estimated Fair Value	$36,185	$43,126	[1]

[1]	The Condensed Consolidated Balance Sheet as of December 31, 2012 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.

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012
	Sep. 30, 2013	Level II [Member]	Level II [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Fair value transfers between Levels	$0	'	'
Severance pay assets	'	$3,700,000	$3,200,000

Fair_Value_of_Financial_Instru3

Fair Value of Financial Instruments - Assets and Liabilities Subject to Fair Value Measurements on Recurring Basis (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	$73,625	$74,725
Prepaid expenses and other current assets [Member] \| Foreign Exchange Forward Contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Prepaid expenses and other current assets	745	1,226
Cash and cash equivalents [Member] \| Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	24,097	17,745
Cash and cash equivalents [Member] \| Corporate debt obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	'	702
Cash and cash equivalents [Member] \| Bank deposits [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	10,710	10,107
Cash and cash equivalents [Member] \| Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	2,633	3,045
Short-term investments [Member] \| Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	1,000
Short-term investments [Member] \| Corporate debt obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	26,032	29,062
Short-term investments [Member] \| Bank deposits [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	10,153	10,057
Short-term investments [Member] \| US agency securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	1,001
Short-term investments [Member] \| Mutual funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	2,006
Level I [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	2,633	5,051
Level I [Member] \| Prepaid expenses and other current assets [Member] \| Foreign Exchange Forward Contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Prepaid expenses and other current assets	'	'
Level I [Member] \| Cash and cash equivalents [Member] \| Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	'	'
Level I [Member] \| Cash and cash equivalents [Member] \| Bank deposits [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	'	'
Level I [Member] \| Cash and cash equivalents [Member] \| Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	2,633	3,045
Level I [Member] \| Short-term investments [Member] \| Corporate debt obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	'
Level I [Member] \| Short-term investments [Member] \| Bank deposits [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	'
Level I [Member] \| Short-term investments [Member] \| Mutual funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	2,006
Level II [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	70,992	69,674
Level II [Member] \| Prepaid expenses and other current assets [Member] \| Foreign Exchange Forward Contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Prepaid expenses and other current assets	745	1,226
Level II [Member] \| Cash and cash equivalents [Member] \| Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	24,097	17,745
Level II [Member] \| Cash and cash equivalents [Member] \| Corporate debt obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	'	702
Level II [Member] \| Cash and cash equivalents [Member] \| Bank deposits [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	10,710	10,107
Level II [Member] \| Cash and cash equivalents [Member] \| Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	'	'
Level II [Member] \| Short-term investments [Member] \| Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	1,000
Level II [Member] \| Short-term investments [Member] \| Corporate debt obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	26,032	29,062
Level II [Member] \| Short-term investments [Member] \| Bank deposits [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	10,153	10,057
Level II [Member] \| Short-term investments [Member] \| US agency securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	1,001
Level III [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	'
Level III [Member] \| Prepaid expenses and other current assets [Member] \| Foreign Exchange Forward Contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Prepaid expenses and other current assets	'	'
Level III [Member] \| Cash and cash equivalents [Member] \| Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	'	'
Level III [Member] \| Cash and cash equivalents [Member] \| Corporate debt obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	'	'
Level III [Member] \| Cash and cash equivalents [Member] \| Bank deposits [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	'	'
Level III [Member] \| Cash and cash equivalents [Member] \| Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	'	'
Level III [Member] \| Short-term investments [Member] \| Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	'
Level III [Member] \| Short-term investments [Member] \| Corporate debt obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	'
Level III [Member] \| Short-term investments [Member] \| Bank deposits [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	'
Level III [Member] \| Short-term investments [Member] \| US agency securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	'
Level III [Member] \| Short-term investments [Member] \| Mutual funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets	'	'

Derivative_Instruments_Additio

Derivative Instruments - Additional Information (Detail)	9 Months Ended
Derivative Instruments - Additional Information (Detail)	Sep. 30, 2013
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Forward exchange contract maturity	'12 months

Derivative_Instruments_Derivat

Derivative Instruments - Derivative Instruments Measured at Fair Value (Detail) (Foreign Exchange Forward Contracts [Member], Prepaid expenses and other current assets [Member], USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]	'	'
Derivative Fair Value	$745	$1,226
Designated as Hedging Instrument [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Notional Amount	5,076	20,513
Derivative Fair Value	692	1,117
Not Designated as Hedging Instrument [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Notional Amount	677	2,296
Derivative Fair Value	$53	$109

Derivative_Instruments_Gains_L

Derivative Instruments - Gains (Losses) on Derivative Instruments and Classification on Condensed Consolidated Statement of Operations (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Designated as Hedging Instrument [Member]	'	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'	'
Gains recognized in OCI	$240	$223	$726	$223
Losses recognized in OCI	-7	-115	-7	-225
Gains reclassified from accumulated OCI into net loss	561	'	1,144	'
Losses reclassified from accumulated OCI into net loss	'	-283	'	-464
Losses recognized in net loss	'	'	'	-5
Not Designated as Hedging Instrument [Member]	'	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'	'
Gains recognized in net loss	40	47	25	117
Losses recognized in net loss	'	'	($15)	($17)

Derivative_Instruments_Gains_L1

Derivative Instruments - Gains (Losses) on Derivative Instruments and Classification on Condensed Consolidated Statement of Operations (Parenthetical) (Detail) (Unrealized gain (loss) on cash flow hedges [Member], Designated as Hedging Instrument [Member], USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Operating expenses [Member]	'	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'	'
Cash flow hedge loss reclassified	$36	($17)	$75	($31)
Cost of revenues [Member]	'	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'	'
Cash flow hedge loss reclassified	$525	($266)	$1,069	($433)

Revolving_Credit_Facility_Addi

Revolving Credit Facility - Additional Information (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Credit Facilities [Line Items]	'	'
Maximum credit facility	$6	'
Outstanding credit facility	0	0
Credit facility expiration date	1-May-14	'
Minimum cash and cash equivalents	$3	'
Percentage in payment of unused line fee	0.25%	'
Line of Credit [Member]	'	'
Credit Facilities [Line Items]	'	'
Variable interest rate basis, description	'LIBOR	'
LIBOR plus interest rate	2.75%	'

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012		Dec. 31, 2010
Loss Contingencies [Line Items]	'	'	'		'
Operating lease expiration year start	'2015	'	'		'
Operating lease expiration year end	'2018	'	'		'
Restricted cash	$1,252,000	'	$753,000	[1]	'
Operating Lease Expense [Member]	'	'	'		'
Loss Contingencies [Line Items]	'	'	'		'
Rent expense	2,500,000	1,500,000	'		'
Tenant improvement allowance	'	'	336,000		639,000
Restricted cash	1,300,000	'	'		'
Cancelable Lease Agreement [Member]	'	'	'		'
Loss Contingencies [Line Items]	'	'	'		'
Penalties	85,000	'	'		'
Motor vehicle lease expenses	1,800,000	1,500,000	'		'
Purchase Commitments [Member]	'	'	'		'
Loss Contingencies [Line Items]	'	'	'		'
Commitments purchased	$4,600,000	'	$3,200,000		'
Period of purchase commitment of inventory from specified date	'9 months	'	'		'

[1]	The Condensed Consolidated Balance Sheet as of December 31, 2012 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.

Commitments_and_Contingencies_2

Commitments and Contingencies - Future Minimum Payments Under Operating Leases and Minimum Rentals to be Received Under Non-Cancellable Subleases (Detail) (USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified	Sep. 30, 2013
Commitments And Contingencies Disclosure [Abstract]	'
2013 (remaining 3 months)	$181
2014	578
2015	240
2016	80
2017	0
Thereafter	0
Total	1,079
2013 (remaining 3 months)	1,047
2014	4,621
2015	2,323
2016	2,357
2017	1,615
Thereafter	279
Total	$12,242

Stock_Plans_Additional_Informa

Stock Plans - Additional Information (Detail) (USD $)

9 Months Ended

12 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

In Millions, except Share data, unless otherwise specified

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Sep. 30, 2013

Jan. 31, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 09, 2011

Sep. 30, 2013

Feb. 29, 2012

Jan. 31, 2013

Jan. 31, 2012

Sep. 30, 2011

Sep. 09, 2011

Sep. 30, 2011

Sep. 30, 2013

Sep. 30, 2012

Mar. 31, 2010

Sep. 30, 2013

Restricted stock units for common stock [Member]

Restricted shares of common stock subject to repurchase [Member]

Maximum [Member]

Minimum [Member]

2003 Stock Plan [Member]

2011 Stock Option and Incentive Plan [Member]

2011 Employee Stock Purchase Plan [Member]

Incapsula 2010 Share Incentive Plan [Member]

Early Exercise of Stock Options [Member]

Restricted shares of common stock subject to repurchase [Member]

Stock options to purchase common stock [Member]

Restricted stock units for common stock [Member]

Maximum [Member]

Period

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Maximum percentage of fair value of common stock on grant date

85.00%

Minimum percentage of combined voting power

10.00%

Maximum percentage of option price of fair value

110.00%

Vesting period

'60 months

'48 months

'4 years

Expiration period

'10 years

Reserve of common stock issuance

1,000,000

500,000

20,000,000

4,733,333

Increase percentage of common stock outstanding

4.00%

1.00%

Shares available for grant

1,967,336

Increase in reserve share

971,843

242,961

Maximum percentage of fair value of common stock on grant date

100.00%

85.00%

Vesting period of RSUs

'4 years

Vesting percentage at each year

25.00%

Remaining vesting period of RSUs

'3 years

Percentage in payroll of deduction base salary to acquire shares of common stock

15.00%

Offering period

'24 months

Number of purchase period for offering

Number of years, shares reserved for issuance will increase

'8 years

Intrinsic value of options exercised

$20

Market value of common stock

$42.02

Compensation cost related to unvested stock-based awards granted, but not yet recognized

29.8

Nonvested awards, compensation cost not yet recognized, period for recognition

'2 years 7 months 6 days

Capitalized stock-based compensation cost

Restricted common stock granted

539,589

843,819

Weighted-average grant date fair value

$1.94

Unvested shares

898,119

446,915

329,616

54,375

Stock_Plans_Option_Activity_Un

Stock Plans - Option Activity Under Incapsula Plan (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Weighted Average Exercise Price, Outstanding - January 1, 2013	$14.08
Weighted Average Exercise Price, Granted	$36.25
Weighted Average Exercise Price, Exercised	$6.15
Weighted Average Exercise Price, Forfeited	$23.22
Weighted Average Exercise Price, Outstanding - September 30, 2013	$22.96
Number of Stock Options Outstanding, Outstanding - January 1, 2013	1,989,237
Number of Stock Options Outstanding, Granted	598,283
Number of Stock Options Outstanding, Exercised	-580,972
Number of Stock Options Outstanding, Forfeited	-180,017
Number of Stock Options Outstanding, Outstanding - September 30, 2013	1,826,531
Incapsula Plan [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Weighted Average Exercise Price, Outstanding - January 1, 2013	$0.10
Weighted Average Exercise Price, Granted	$0.40
Weighted Average Exercise Price, Exercised	$0.02
Weighted Average Exercise Price, Forfeited	$0.22
Weighted Average Exercise Price, Outstanding - September 30, 2013	$0.30
Number of Stock Options Outstanding, Outstanding - January 1, 2013	1,836,500
Number of Stock Options Outstanding, Granted	397,500
Number of Stock Options Outstanding, Exercised	-1,123,750
Number of Stock Options Outstanding, Forfeited	-129,375
Number of Stock Options Outstanding, Outstanding - September 30, 2013	980,875
Shares Available for Grant, Outstanding - January 1, 2013	2,753,708
Shares Available for Grant, Granted	-397,500
Shares Available for Grant, Exercised	'
Shares Available for Grant, Forfeited	129,375
Shares Available for Grant, Outstanding - September 30, 2013	2,485,583

Stock_Plans_StockBased_Compens

Stock Plans - Stock-Based Compensation Expense (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Total stock-based compensation expense	$3,413	$1,762	$9,858	$3,596
Cost of revenues [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Total stock-based compensation expense	254	143	722	302
Research and development [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Total stock-based compensation expense	747	372	2,133	759
Sales and marketing [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Total stock-based compensation expense	1,620	665	4,596	1,365
General and administrative [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Total stock-based compensation expense	$792	$582	$2,407	$1,170

Stock_Plans_Weighted_Average_A

Stock Plans - Weighted Average Assumptions for Fair Value of Stock Options Granted to Employees (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Stock options to purchase common stock [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Dividend rate	0.00%	0.00%	0.00%	0.00%
Risk-free interest rate	1.80%	0.80%	1.20%	1.00%
Expected term (in years)	'6 years 1 month 6 days	'6 years 1 month 6 days	'6 years 1 month 6 days	'6 years
Expected volatility	47.00%	46.00%	46.00%	48.00%
ESPP [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Dividend rate	'	'	0.00%	0.00%
Risk-free interest rate	'	'	0.10%	0.20%
Expected term (in years)	'	'	'6 months	'6 months
Expected volatility	'	'	31.00%	38.00%

Stock_Plans_Summary_of_Option_

Stock Plans - Summary of Option Activity Under 2003 Plan and 2011 Plan and Related Information (Detail) (USD $)	9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Aggregate Intrinsic Value, Balances - January 1, 2013	$35,513
Aggregate Intrinsic Value, Balances - September 30, 2013	35,052
Options exercisable, Aggregate Intrinsic Value	$14,380
Weighted Average Remaining Contractual Life (in years), Balances - January 1, 2013	'8 years 1 month 2 days
Weighted Average Remaining Contractual Life (in years), Balances - September 30, 2013	'8 years 2 months 16 days
Options exercisable, Weighted Average Remaining Contractual Life (Years)	'6 years 11 months 19 days
Weighted Average Exercise Price, Outstanding - January 1, 2013	$14.08
Weighted Average Exercise Price, Granted	$36.25
Weighted Average Exercise Price, Exercised	$6.15
Weighted Average Exercise Price, Cancelled or forfeited	$23.22
Weighted Average Exercise Price, Outstanding - September 30, 2013	$22.96
Weighted Average Exercise Price, Options exercisable	$11.90
Number of Stock Options Outstanding, Outstanding - January 1, 2013	1,989,237
Number of Stock Options Outstanding, Granted	598,283
Number of Stock Options Outstanding, Exercised	-580,972
Number of Stock Options Outstanding, Cancelled or forfeited	-180,017
Number of Stock Options Outstanding, Outstanding - September 30, 2013	1,826,531
Number of Shares, Options exercisable	477,469

Stock_Plans_Summary_of_RSU_Act

Stock Plans - Summary of RSU Activity Under 2003 Plan and 2011 Plan Outstanding and Weighted Average Grant Date Fair Value (Detail) (Restricted stock units for common stock [Member], USD $)	9 Months Ended
	Sep. 30, 2013
Restricted stock units for common stock [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of Restricted Stock Units Outstanding, Beginning Balance	446,915
Number of Restricted Stock Units Outstanding, Granted	539,589
Number of Restricted Stock Units Outstanding, Released	-27,536
Number of Restricted Stock Units Outstanding, Cancelled or expired	-60,849
Number of Restricted Stock Units Outstanding, Ending Balance	898,119
Weighted-Average Grant Date Fair Value, Beginning Balance	$31.20
Weighted-Average Grant Date Fair Value, Granted	$36.56
Weighted-Average Grant Date Fair Value, Released	$34.13
Weighted-Average Grant Date Fair Value, Cancelled or expired	$33.53
Weighted-Average Grant Date Fair Value, Ending Balance	$34.30

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income - Changes in Balances of Accumulated Other Comprehensive Income (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'		'
Beginning Balance	$556	($510)	$861	[1]	($616)
Other comprehensive income (loss) before reclassifications	302	231	742		131
Amounts reclassified to net loss	-605	311	-1,350		517
Other comprehensive income (loss)	-303	542	-608		648
Ending Balance	253	32	253		32
Unrealized gain (loss) on cash flow hedges [Member]	'	'	'		'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'		'
Beginning Balance	593	-488	690		-559
Other comprehensive income (loss) before reclassifications	233	108	719		-2
Amounts reclassified to net loss	-561	283	-1,144		464
Other comprehensive income (loss)	-328	391	-425		462
Ending Balance	265	-97	265		-97
Unrealized gain (loss) on investments [Member]	'	'	'		'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'		'
Beginning Balance	-37	-22	171		-57
Other comprehensive income (loss) before reclassifications	69	123	23		133
Amounts reclassified to net loss	-44	28	-206		53
Other comprehensive income (loss)	25	151	-183		186
Ending Balance	($12)	$129	($12)		$129

[1]	The Condensed Consolidated Balance Sheet as of December 31, 2012 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.

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Income - Summary of Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Current period unrealized gain (loss) on cash flow hedges, Pre-Tax Amount	$233	$108	$719	($2)
Reclassification adjustments on cash flow hedges, Pre-Tax Amount	-561	283	-1,144	464
Unrealized gains (losses) on cash flow hedges, net, Pre-Tax Amount	-328	391	-425	462
Current period unrealized gain (loss) on investments, Pre-Tax Amount	69	123	23	133
Reclassification adjustments on investments, Pre-Tax Amount	-44	28	-206	53
Unrealized gains (losses) on investments, net, Pre-Tax Amount	25	151	-183	186
Other comprehensive income/(loss), Pre-Tax Amount	-303	542	-608	648
Current period unrealized gain (loss) on cash flow hedges, Tax Expense (Benefit)	'	'	'	'
Reclassification adjustments on cash flow hedges, Tax Expense (Benefit)	'	'	'	'
Unrealized gains (losses) on cash flow hedges, net, Tax Expense (Benefit)	'	'	'	'
Current period unrealized gain (loss) on investments, Tax Expense (Benefit)	'	'	'	'
Reclassification adjustments on investments, Tax Expense (Benefit)	'	'	'	'
Unrealized gains (losses) on investments, net, Tax Expense (Benefit)	'	'	'	'
Other comprehensive income/(loss), Tax Expense (Benefit)	'	'	'	'
Current period unrealized gain (loss) on cash flow hedges, After-Tax Amount	233	108	719	-2
Reclassification adjustments on cash flow hedges, After-Tax Amount	-561	283	-1,144	464
Unrealized gains (losses) on cash flow hedges, net, After-Tax Amount	-328	391	-425	462
Current period unrealized gain (loss) on investments, After-Tax Amount	69	123	23	133
Reclassification adjustments on investments, After-Tax Amount	-44	28	-206	53
Unrealized gains (losses) on investments, net), After-Tax Amount	25	151	-183	186
Other comprehensive income/(loss), After-Tax Amount	($303)	$542	($608)	$648

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]	'	'	'	'
Income tax expense	$0.30	$0.30	$0.70	$0.60

Segment_Information_Additional

Segment Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2013
	Segment
Segment Reporting [Abstract]	'
Number of operating segments	2

Segment_Information_Summary_of

Segment Information - Summary of Company's Operating Segments (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]	'	'	'	'	'
Net revenue	$35,102	$26,344	$95,026	$72,416	'
Operating loss	-3,745	-1,662	-15,468	-6,262	'
Provision for income tax	288	262	703	642	'
Net loss	-3,775	-1,859	-15,749	-6,663	'
Depreciation and amortization	'	'	1,935	1,312	'
Stock-based compensation	'	'	9,858	3,596	'
Total assets	160,298	'	160,298	'	153,957	[1]
Imperva [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Net revenue	34,259	26,122	93,147	71,941	'
Operating loss	-2,848	-957	-12,718	-4,238	'
Provision for income tax	263	224	674	597	'
Net loss	-3,022	-1,134	-13,552	-4,783	'
Depreciation and amortization	576	427	1,682	1,237	'
Stock-based compensation	3,387	1,755	9,816	3,575	'
Total assets	158,158	136,401	158,158	136,401	'
Incapsula [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Net revenue	843	222	1,879	475	'
Operating loss	-897	-705	-2,750	-2,024	'
Provision for income tax	25	38	29	45	'
Net loss	-898	-857	-2,608	-2,247	'
Depreciation and amortization	89	35	253	75	'
Stock-based compensation	26	7	42	21	'
Total assets	$2,140	$4,378	$2,140	$4,378	'

[1]	The Condensed Consolidated Balance Sheet as of December 31, 2012 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.

Segment_Information_Components

Segment Information - Components of Net Services Revenue (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total net services revenue	$16,924	$11,667	$47,023	$31,643
Maintenance and support [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total net services revenue	11,139	8,582	31,926	24,072
Professional services and training [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total net services revenue	2,724	1,749	7,495	4,589
Subscriptions [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total net services revenue	$3,061	$1,336	$7,602	$2,982

Segment_Information_Companys_N

Segment Information - Company's Net Revenue by Geographic Region, Based on Customer's Location (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total net revenue	$35,102	$26,344	$95,026	$72,416
Americas [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total net revenue	19,941	16,226	58,168	43,341
EMEA [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total net revenue	9,737	5,623	22,239	16,412
APAC [Member]	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Total net revenue	$5,424	$4,495	$14,619	$12,663

Segment_Information_LongLived_

Segment Information - Long-Lived Assets by Location (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Total long-lived assets	$5,333	$5,515
United States [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Total long-lived assets	2,914	2,851
Israel [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Total long-lived assets	2,409	2,642
Other [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Total long-lived assets	$10	$22

Net_Loss_per_Share_Antidilutiv

Net Loss per Share - Antidilutive Securities Excluded from Computation of Diluted Net Loss Per Share of Common Stock (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Stock options to purchase common stock [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive securities excluded from computation of earnings per share	1,826,531	2,213,529	1,826,531	2,213,529
Restricted stock units for common stock [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive securities excluded from computation of earnings per share	898,119	380,393	898,119	380,393
Restricted shares of common stock subject to repurchase [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive securities excluded from computation of earnings per share	383,991	579,708	383,991	579,708
Common stock warrants [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive securities excluded from computation of earnings per share	'	8,333	'	8,333

Related_Party_Transaction_Addi

Related Party Transaction - Additional Information (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2012
Related Party Transactions [Abstract]	'
Net revenues recorded from indirect sales	$0.30

Subsequent_Event_Additional_In

Subsequent Event - Additional Information (Detail) (Subsequent Event [Member], USD $)	1 Months Ended
In Millions, except Share data, unless otherwise specified	Oct. 31, 2013
Incapsula [Member]	'
Subsequent Event [Line Items]	'
Loaned to subsidiaries	$1.10
Interest rate on loans	2.00%
Maturity of loans	31-Dec-14
Incapsula [Member] \| Restricted stock units for common stock [Member]	'
Subsequent Event [Line Items]	'
Shares issuable, as-converted to common stock-basis	204,820
Imperva [Member] \| Restricted stock units for common stock [Member]	'
Subsequent Event [Line Items]	'
Business acquisition, shares issuable	264,878