Maximum offering period for the employee stock purchase plan.

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- Definition

The percentage increase of common stock outstanding.

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No definition available.

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- Definition

Minimum Percentage Of Combined Voting Power

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- Definition

Number of years at the beginning of which the number of shares reserved will be increased.

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Maximum number of purchases over the offering period.

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- Definition

Aggregate grant-date fair value of stock options.

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No definition available.

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Share Based Compensation Arrangement By Share Based Payment Award Options Nonvested Intrinsic Value

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- Definition

Number of shares of equity interests issued or issuable to acquire entity.

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Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

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Aggregate number of common shares reserved for future issuance.

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The number of new shares issued in the conversion of stock in a noncash (or part noncash) transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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Represents the compensation cost capitalized during the period arising from equity-based compensation arrangements (for example, shares of stock, units, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Aggregate proceeds received by the entity during the annual period from exercises of stock or unit options and conversion of similar instruments granted under equity-based payment arrangements.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Unrecognized cost of unvested options awarded to employees as compensation.

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No definition available.

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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The cash outflow for cost incurred directly with the issuance of an equity security.

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The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

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Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

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Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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The cash inflow from the additional capital contribution to the entity.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Description of award terms as to how many shares or portion of an award are no longer contingent on satisfaction of either a service condition, market condition or a performance condition, thereby giving the employee the legal right to convert the award to shares, to sell the shares, and be entitled to the cash proceeds of such sale. For example, vesting may be expressed as being 25 percent of the shares under option on each anniversary of the grant date.

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- Definition

Discount rate from fair value on offering date that participants pay for shares.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

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- Definition

Number of additional shares authorized for issuance under an established share-based compensation plan.

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No definition available.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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- Definition

Gross number of share options (or share units) granted during the period.

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No definition available.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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The addition or reduction in the number of reserved shares that could potentially be issued under the option plan attributable to reasons other than grants, exercises, forfeitures, and expirations during the reporting period.

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Percentage of vesting of share-based compensation awards.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of non-vested options outstanding.

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Number of options vested.

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Purchase price of common stock expressed as a percentage of its fair value.

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Per share or per unit amount of equity securities issued.

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Number of new stock issued during the period.

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Capital Stock - Additional Information (Detail)		1 Months Ended							12 Months Ended
Capital Stock - Additional Information (Detail)	Feb. 07, 2014 $ / shares shares	Oct. 31, 2015 shares	Mar. 31, 2015 USD ($) $ / shares shares	Aug. 31, 2014 shares	Mar. 31, 2014 shares	Nov. 30, 2013 shares	Jan. 31, 2012	Sep. 30, 2011 Period shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares	Dec. 31, 2010 $ / shares shares	Mar. 31, 2010 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, shares authorized									5,000,000	5,000,000
Preferred stock, shares outstanding									0	0
Preferred stock, shares issued									0	0
Reserve of common stock for future issuance									5,547,165	6,585,454
Performance-based restricted stock units granted									911,734	1,368,761
Number of stock option outstanding, granted									696,971	1,256,559	631,775
Weighted-average grant date fair value \| $ / shares									$ 23.75	$ 19.36	$ 16.48
Aggregate grant date fair value, stock options granted \| $									$ 16,600,000	$ 24,300,000	$ 7,300,000
Aggregate grant date fair value, stock options vested \| $									11,700,000	7,200,000	4,600,000
Intrinsic value of options exercised \| $									21,600,000	14,700,000	23,200,000
Compensation cost related to unvested stock-based awards granted, but not yet recognized \| $									$ 92,600,000
Nonvested awards, compensation cost not yet recognized, period for recognition									2 years 7 months 6 days
Net cash proceeds from the exercise of stock options \| $									$ 12,100,000	8,500,000	6,300,000
Capitalized stock-based compensation cost \| $									0	0	0
Recognized stock-based compensation tax benefits \| $									$ 165,000	$ 385,000	$ 0
Weighted-average grant date fair value \| $ / shares									$ 53.02	$ 41.66
Issuance in connection with restricted stock units outstanding									1,898,025	2,279,081	1,044,651
Assumed common stock options in acquisitions										72,607
Aggregate net proceeds from sale of common stock, net of underwriting discounts, commissions and offering costs \| $									$ 23,524,000	$ 10,546,000	$ 7,568,000
Follow-On Public Offering [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock, shares			3,450,000
Sale of common stock, price per share \| $ / shares			$ 39.00
Aggregate net proceeds from sale of common stock, net of underwriting discounts, commissions and offering costs \| $			$ 127,900,000
Underwriting discounts, commissions and other offering expenses \| $			$ 6,700,000
Incapsula Acquisition [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Business acquisition purchase price, shares issued					124,088
Skyfence Networks Ltd. [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested awards, compensation cost not yet recognized, period for recognition	4 years
Common stock, shares vested									236,537	0
Business acquisition purchase price, shares issued	884,422
Closing price of stock \| $ / shares	$ 59.08
Skyfence Networks Ltd. [Member] \| Incapsula [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Assumed common stock options in acquisitions									72,607
Stock options [Member] \| Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested shares									0	6,667	45,000
Unvested shares, value \| $										$ 71,000	$ 400,000
Restricted Stock Units for Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Restricted Stock Units Vested in Period \| $									$ 31,400,000	$ 8,300,000	$ 6,000,000
Restricted Stock Units for Common Stock [Member] \| Incapsula [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issuable, as-converted to common stock-basis						198,825
Restricted Stock Units And Options Outstanding [Member] \| Incapsula [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issuable, as-converted to common stock-basis									247,184
Restricted Shares of Common Stock Subject to Repurchase [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-based restricted stock units granted									0	0	0	843,819
Weighted-average grant date fair value \| $ / shares												$ 1.94
Common stock, shares vested									843,819
Issuance in connection with restricted stock units outstanding										210,954
Restricted Shares of Common Stock Subject to Repurchase [Member] \| Skyfence Networks Ltd. [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Business acquisition purchase price, shares issued	532,262
Maximum [Member] \| Restricted Shares of Common Stock Subject to Repurchase [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period									60 months
Minimum [Member] \| Restricted Shares of Common Stock Subject to Repurchase [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period									48 months
2003 Stock Plan [Member] \| Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum percentage of fair value of common stock on grant date									85.00%
2003 Stock Plan [Member] \| Maximum [Member] \| Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period									10 years
2003 Stock Plan [Member] \| Minimum [Member] \| Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period									4 years
2011 Stock Option and Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserve of common stock for future issuance								1,000,000
Increase percentage of common stock outstanding									4.00%
Shares available for grant									1,166,742
Increase in reserve share									1,075,819
2011 Stock Option and Incentive Plan [Member] \| Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum percentage of fair value of common stock on grant date									100.00%
Expiration period									10 years
2011 Stock Option and Incentive Plan [Member] \| Restricted Stock Units for Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period									4 years
Description of vesting terms									The Company began granting RSUs in February 2012, which generally vest either over 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.
2011 Stock Option and Incentive Plan [Member] \| Restricted Stock Units for Common Stock [Member] \| Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage at the end of period									25.00%
2011 Stock Option and Incentive Plan [Member] \| Restricted Stock Units for Common Stock [Member] \| Incapsula Acquisition [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-based restricted stock units granted									264,878
2011 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserve of common stock for future issuance								500,000
Increase percentage of common stock outstanding							1.00%
Increase in reserve share										268,955
Percentage in payroll of deduction base salary to acquire shares of common stock								15.00%
Offering period								24 months
Percentage of fair value of common stock on offering period								85.00%
Number of years, shares reserved for issuance will increase							8 years
2011 Employee Stock Purchase Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserve of common stock for future issuance								20,000,000
Number of purchase periods for offering \| Period								5
Inducement Stock Option Plan And Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Description of vesting terms									In accordance with the terms of the Inducement Option Plans, the Company issued options to purchase up to 290,000 shares of the Company’s common stock at an exercise price equal to the fair market value of a share of the Company’s common stock on the dates of grant of the options. The options, which will have a ten-year term, will vest at the rate of 25% of the shares on each of the first anniversary of the vesting commencement date with an additional 6.25% of the shares subject to the option vesting each quarter thereafter so long as the participant has not been terminated.
Number of stock option outstanding, granted				290,000
Inducement Stock Option Plan And Agreement [Member] \| Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage at the end of period				25.00%
Inducement Stock Option Plan And Agreement [Member] \| Quarterly Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage at the end of period				6.25%
Inducement Restricted Stock Unit Plan and Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant				290,000
Description of vesting terms									In accordance with the terms of the Inducement RSU Plans, the Company issued RSUs representing a total of 290,000 shares of the Company’s common stock. The RSUs, which will expire following settlement, will vest at the rate of 25% of the shares on each of the first anniversary of the vesting commencement date with an additional 6.25% of the shares subject to the RSU vesting each quarter thereafter so long as the participant has not been terminated.
Inducement Restricted Stock Unit Plan and Agreement [Member] \| Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage at the end of period				25.00%
Inducement Restricted Stock Unit Plan and Agreement [Member] \| Quarterly Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage at the end of period				6.25%
2015 Equity Inducement Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserve of common stock for future issuance		100,000
2015 Equity Inducement Plan [Member] \| Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum percentage of fair value of common stock on grant date		100.00%
Expiration period		10 years
Incapsula 2010 Share Incentive Plan [Member] \| Restricted Stock Units for Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-based restricted stock units granted						7,095,461
Incapsula 2010 Share Incentive Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserve of common stock for future issuance													4,733,333
Greater 10% Ownership [Member] \| 2003 Stock Plan [Member] \| Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum percentage of fair value of common stock on grant date									110.00%
Minimum percentage of combined voting power									10.00%