Proofpoint (PFPT) 10-K 26 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Feb. 13, 2015	Jun. 30, 2014
Document Information [Abstract]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Entity Registrant Name	PROOFPOINT INC
Entity Central Index Key	1212458
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		38,993,942
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$1,291

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$180,337	$243,786
Short-term investments	34,649	8,015
Accounts receivable, net of allowance for doubtful accounts of $429 and $276 at December 31, 2014 and 2013, respectively	40,912	26,221
Inventory	499	860
Deferred product costs	1,847	1,004
Prepaid expenses and other current assets	7,994	7,963
Total current assets	266,238	287,849
Property and equipment, net	18,718	11,221
Deferred product costs	307	357
Goodwill	107,504	63,764
Intangible assets, net	27,086	22,976
Other assets	4,397	4,392
Total assets	424,250	390,559
Current liabilities:
Accounts payable	9,249	7,281
Accrued liabilities	24,220	19,260
Notes payable and lease obligations	695	1,655
Deferred rent	569	297
Deferred revenue	123,550	89,450
Total current liabilities	158,283	117,943
Convertible senior notes	161,630	152,928
Long-term notes payable and lease obligations	0	695
Long-term deferred rent	2,099	56
Other long-term liabilities	6,640	7,244
Long-term deferred revenue	39,125	34,533
Total liabilities	367,777	313,399
Commitments and contingencies (Note 7)
Stockholders' equity:
Convertible preferred stock, $0.0001 par value; 5,000 shares authorized; no shares issued and outstanding as of December 31, 2014 and 2013	0	0
Common stock, $0.0001 par value; 200,000 shares authorized at December 31, 2014 and 2013; 38,665 and 36,140 shares issued and outstanding at December 31, 2014 and 2013, respectively	4	4
Additional paid-in capital	330,744	287,165
Accumulated other comprehensive loss	-27	0
Accumulated deficit	-274,248	-210,009
Total stockholders' equity	56,473	77,160
Total liabilities and stockholders' equity	$424,250	$390,559

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Allowance for doubtful accounts	$429	$276
Preferred stock:
Preferred stock authorized (in shares)	5,000,000
Number of shares of common stock reserved for future issuance
Par value of common stock (USD per share)	$0.00	$0.00
Common stock authorized (in shares)	200,000,000	200,000,000
Common stock issued (in shares)	38,665,000	36,140,000
Common stock outstanding (in shares)	38,665,000	36,140,000
Convertible preferred stock [Member]
Preferred stock:
Par value of preferred stock (USD per share)	$0.00	$0.00
Preferred stock authorized (in shares)	5,000,000	5,000,000
Preferred stock issued (in shares)	0	0
Preferred stock outstanding (in shares)	0	0

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Revenue:
Subscription	$187,527		$132,062		$101,470
Hardware and services	8,080		5,869		4,825
Total revenue	195,607		137,931		106,295
Cost of revenue:
Subscription	53,136		35,438		28,246
Hardware and services	12,543		6,124		4,867
Total cost of revenue	65,679	[1],[2]	41,562	[1],[2]	33,113	[1],[2]
Gross profit	129,928		96,369		73,182
Operating expense:
Research and development	51,903		34,449		24,827
Sales and marketing	102,455		71,781		55,239
General and administrative	26,679		19,622		12,693
Total operating expense	181,037	[1],[2]	125,852	[1],[2]	92,759	[1],[2]
Operating loss	-51,109		-29,483		-19,577
Interest expense, net	-11,213		-641		-108
Other expense, net	-2,230		-215		-154
Loss before benefit from (provision for) income taxes	-64,552		-30,339		-19,839
Benefit from (provision for) income taxes	313		2,808		-521
Net loss	-64,239		-27,531		-20,360
Net loss per share, basic and diluted (in dollars per share)	($1.72)		($0.79)		($0.85)
Weighted average shares outstanding, basic and diluted (in shares)	37,381		34,874		24,056
Intangible amortization expense	8,790		4,044		3,276
Cost of subscription revenue [Member]
Operating expense:
Stock-based compensation expense	2,404		1,007		657
Intangible amortization expense	4,157		2,220		2,785
Cost of hardware and services revenue [Member]
Operating expense:
Stock-based compensation expense	604		196		70
Research and development [Member]
Operating expense:
Stock-based compensation expense	10,204		3,608		1,869
Intangible amortization expense	93		47		30
Sales and marketing [Member]
Operating expense:
Stock-based compensation expense	10,795		4,270		3,103
Intangible amortization expense	4,494		1,743		461
General and administrative [Member]
Operating expense:
Stock-based compensation expense	6,997		3,002		1,622
Intangible amortization expense	$46		$34		$0
[1]	Includes stock-based compensation expenses as follows:Cost of subscription $2,404, cost of hardware and service revenue $604, research and development $10,204, sales and marketing $10,795 and general and administrative $6,997 for the year ended DecemberB 31, 2014. Cost of subscription $1,007, cost of hardware and service revenue $196, research and development $3,608, sales and marketing $4,270 and general and administrative $3,002 for the year ended DecemberB 31, 2013. Cost of subscription $657, cost of hardware and service revenue $70, research and development $1,869, sales and marketing $3,103 and general and administrative $1,622 for the year ended DecemberB 31, 2012
[2]	Includes intangible amortization expense as follows: Cost of subscription revenue $4,157, research and development $93, sales and marketing $4,494 and general and administrative $46 for the year ended DecemberB 31, 2014. Cost of subscription revenue $2,220, research and development $47, sales and marketing $1,743 and general and administrative $34 for the year ended DecemberB 31, 2013. Cost of subscription revenue $2,785, research and development $30, sales and marketing $461 and general and administrative $0 for the year ended DecemberB 31, 2012.

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Comprehensive Loss (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net loss	($64,239)	($27,531)	($20,360)
Other comprehensive income (loss), net of tax:
Unrealized (losses) gains on investments, net	-27	-3	6
Comprehensive loss	($64,266)	($27,534)	($20,354)

Consolidated_Statements_of_Cha

Consolidated Statements of Changes in Convertible Preferred Stock and Stockholders' Equity (Deficit) (USD $)	Total	Convertible preferred stock [Member]	Convertible Preferred Stock [Member]	Common stock [Member]	Additional paid-in capital [Member]	Accumulated other comprehensive income (loss) [Member]	Accumulated deficit [Member]
In Thousands, except Share data, unless otherwise specified
Beginning balance at Dec. 31, 2011	($137,347)			$1	$24,773	($3)	($162,118)
Convertible preferred stock, beginning balance at Dec. 31, 2011		109,911
Beginning balance (shares) at Dec. 31, 2011				4,961,000
Convertible preferred stock, beginning balance (shares) at Dec. 31, 2011		38,942,000
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of preferred stock into shares of common stock	109,911	-109,911		1	109,910
Conversion of preferred stock into shares of common stock (shares)		38,942,000		19,567,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	-20,360						-20,360
Unrealized gain on short-term investments	6					6
Issuance of common stock as part of the consideration for acquisitions (shares)				21,000
Issuance of common stock in April 2012 initial public offering at $13.00 per share, net of issuance costs of $7,879	68,295			1	68,294
Issuance of common stock in April 2012 initial public offering at $13.00 per share, net of issuance costs of $7,879 (shares)				5,860,000
Stock-based compensation expense	7,321				7,321
Stock options exercised	4,946				4,946
Stock options exercised (shares)				2,543,000
Issuance of common stock under employee stock purchase plan	1,093				1,093
Issuance of common stock under employee stock purchase plan (shares)				99,000
Tax withholding upon vesting of restricted stock awards	-83				-83
Tax withholding upon vesting of restricted stock awards (shares)				-7,000
Vesting of early exercise options	26				26
Ending balance at Dec. 31, 2012	33,808		0	3	216,280	3	-182,478
Ending balance (shares) at Dec. 31, 2012			0	33,044,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	-27,531						-27,531
Unrealized gain on short-term investments	-3					-3
Embedded conversion feature on Convertible Senior Notes	43,293				43,293
Stock-based compensation expense	11,231				11,231
Stock options exercised	13,510			1	13,509
Stock options exercised (shares)	2,879,000			2,879,000
Issuance of common stock under employee stock purchase plan	2,839				2,839
Issuance of common stock under employee stock purchase plan (shares)				217,000
Vesting of early exercise options	13				13
Ending balance at Dec. 31, 2013	77,160		0	4	287,165	0	-210,009
Ending balance (shares) at Dec. 31, 2013			0	36,140,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	-64,239						-64,239
Unrealized gain on short-term investments	-27					-27
Stock-based compensation expense	29,233				29,233
Common stock issued under stock-based compensation plans	18,513				18,513
Common stock issued under stock-based compensation plans (shares)				2,574,000
Tax withholding upon vesting of restricted stock awards	-4,170				-4,170
Tax withholding upon vesting of restricted stock awards (shares)				-105,000
Exercise of warrants				2,000
Issuance of restricted stock (shares)				54,000
Vesting of early exercise options	3				3
Ending balance at Dec. 31, 2014	$56,473		$0	$4	$330,744	($27)	($274,248)
Ending balance (shares) at Dec. 31, 2014			0	38,665,000

Consolidated_Statements_of_Cha1

Consolidated Statements of Changes in Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) (IPO [Member], Common stock [Member], USD $)	0 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Apr. 20, 2012
IPO [Member] | Common stock [Member]
Public offering price (USD per share)	$13
Payments of stock issuance costs	$7,879

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities
Net loss	($64,239)	($27,531)	($20,360)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	17,823	9,967	7,710
Loss on disposal of property and equipment	2	2	0
Amortization of investment premiums, net of accretion of purchase discounts	312	575	520
Provision for allowance for doubtful accounts	175	40	54
Stock-based compensation	31,004	12,083	7,321
Deferred income taxes	-691	-3,458	0
Change in fair value of contingent earn-outs	5	9	0
Amortization of debt issuance costs and accretion of debt discount	8,753	489	0
Changes in assets and liabilities, net of effect of acquisitions:
Accounts receivable	-14,666	-4,500	-2,380
Inventory	328	-223	162
Deferred products costs	-791	149	1,280
Prepaid expenses	-945	636	20
Other current assets	-351	-248	-954
Long-term assets	-23	-316	97
Accounts payable	189	931	-683
Accrued liabilities	3,995	1,883	3,485
Earn-out payment	-13	-1	0
Deferred rent	2,315	-438	-55
Deferred revenue	38,093	22,575	10,619
Net cash provided by operating activities	21,275	12,624	6,836
Cash flows from investing activities
Proceeds from sales and maturities of short-term investments	11,353	59,046	15,264
Purchase of short-term investments	-37,805	-20,376	-60,095
Purchase of property and equipment, net	-14,988	-7,666	-5,904
Acquisitions of business, net of cash acquired	-53,680	-40,972	0
Net cash used in investing activities	-95,120	-9,968	-50,735
Cash flows from financing activities
Proceeds from issuance of common stock, net of repurchases	17,640	16,367	6,143
Withholding taxes related to restricted stock net share settlement	-4,170	0	-83
Proceeds from initial public offering, net of offering costs	0	0	68,295
Proceeds from issuance of convertible senior notes, net of discount and issuance costs	0	195,641	0
Payments of debt issuance costs	-191	0	0
Repayments of notes payable and loans	-1,655	-10,033	-969
Holdback payments for prior acquisitions	-741	0	0
Payment of contingent earn-outs	-487	-99	0
Net cash provided by financing activities	10,396	201,876	73,386
Net (decrease) increase in cash and cash equivalents	-63,449	204,532	29,487
Cash and cash equivalents
Beginning of period	243,786	39,254	9,767
End of period	180,337	243,786	39,254
Supplemental disclosures of cash flow information
Cash paid for interest	2,582	148	49
Cash paid for taxes	491	385	370
Supplemental disclosure of noncash investing and financing activities
Unpaid deferred offering costs	0	195	0
Unpaid purchases of property and equipment	$2,576	$1,039	$659

The_Company_and_Summary_of_Sig

The Company and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
The Company and Summary of Significant Accounting Policies	The Company and Summary of Significant Accounting Policies
	The Company
	Proofpoint, Inc. (the "Company") was incorporated in Delaware in June 2002 and is headquartered in California.
	Proofpoint is a leading security-as-a-service provider that enables large and mid-sized organizations worldwide to defend, protect, archive and govern their most sensitive data. The Company's security-as-a-service platform is comprised of a number of data protection solutions, including threat protection and incident response, regulatory compliance, archiving, governance and eDiscovery, and secure communication.
	Reverse Stock Split
	On March 30, 2012, the Company's Board of Directors approved a 1-for-2 reverse stock split of the Company's common stock. The reverse stock split became effective on April 2, 2012. Upon the effectiveness of the reverse stock split, (i) every two shares of outstanding common stock was decreased to one share of common stock, (ii) the number of shares of common stock into which each outstanding option to purchase common stock is exercisable was proportionally decreased on a 1-for-2 basis, (iii) the exercise price of each outstanding option to purchase common stock was proportionately increased on a 1-for-2 basis, and (iv) the conversion ratio for each share of preferred stock outstanding was proportionately reduced on a 1-for-2 basis. All of the share numbers, share prices, and exercise prices have been retrospectively adjusted to reflect the reverse stock split.
	Principles of Consolidation
	The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.
	In 2014 and 2013, the Company completed a number of acquisitions which are more fully described in Note 2, "Acquisitions". The consolidated financial statements include the results of operations from these business combinations from their date of acquisition.
	Use of Estimates
	The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of expenses during the reporting period. Actual results could differ materially from those estimates. Significant items subject to such estimates and assumptions include those related to revenue recognition, stock-based compensation expense, fair value of assets acquired and liabilities assumed in business combinations, impairment assessments of goodwill, intangible assets and other long-lived assets, loss contingencies, and the recognition and measurement of current and deferred income taxes.
	Foreign Currency Remeasurement and Transactions
	The functional currency for the Company's wholly-owned foreign subsidiaries is the U.S. dollar. Accordingly, the subsidiaries remeasure monetary assets and liabilities at period-end exchange rates, while nonmonetary items are remeasured at historical rates. Income and expense accounts are remeasured at the average exchange rates in effect during the year. Remeasurement adjustments are recognized in the consolidated statements of operations as transaction gains or losses within other income (expense), net, in the period of occurrence. Aggregate transaction gain losses included in determining net loss were $2,182, $180 and $157 for the years ended December 31, 2014, 2013 and 2012, respectively.
	Cash and Cash Equivalents
	The Company considers currency on hand, demand deposits, time deposits, money market funds and all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash and cash equivalents. Cash and cash equivalents are held in various financial institutions in the United States and internationally.
	Investments
	The Company classifies all its investments as available-for-sale at the time of purchase since it is management's intent that these investments be available for current operations, and as such, includes these investments as short-term investments on its balance sheets. These investments consist of fixed-term deposits, commercial paper and investment-grade corporate debt securities with original maturities longer than three months. Short-term investments classified as available-for-sale are recorded at fair value with the related unrealized gains and losses included in accumulated other comprehensive income (loss), a component of stockholders' equity. Realized gains and losses are recorded in the consolidated statements of operations and comprehensive loss based on specific identification.
	Inventories
	Inventories are stated at lower of cost or market value, with costs computed on a first-in, first-out basis. Cost is determined using standard costs which approximate actual costs. The Company periodically reviews its inventories for excess and obsolete items and adjusts carrying costs to estimated net realizable values when they are determined to be less than cost.
	Inventories held at December 31, 2014 and 2013 consist primarily of finished goods.
	Revenue Recognition
	The Company derives its revenue primarily from two sources: (1) subscription revenue for rights related to the use of the security-as-a-service platform and (2) hardware, training and professional services revenue provided to customers related to their use of the platform. The Company records its revenues net of any value added or sales tax. Subscription revenue is derived from a subscription‑based enterprise licensing model with contract terms typically ranging from one to three years, and consists of (i) subscription fees from the licensing of the security-as-a-service platform, (ii) subscription fees for access to the on-demand elements of the platform and (iii) subscription fees for the right to access the Company’s customer support services.
	Revenue is recognized when all of the following criteria have been met:
	•	Persuasive evidence of an arrangement exists;
	•	Delivery has occurred or services have been rendered;
	•	Sales price is fixed or determinable; and
	•	Collectability is reasonably assured.
	The Company applies industry-specific software revenue recognition guidance to transactions involving the licensing of software, as well as related support, training, and other professional services. The Company has analyzed all of the elements included in its multiple element software arrangements and has determined that it does not have sufficient VSOE of fair value to allocate revenue to its subscription and software license agreements, support, training, and professional services. The Company defers all revenue under the software arrangement until the commencement of the subscription services and any associated professional services. Once the subscription services and the associated professional services have commenced, the entire fee from the arrangement is recognized ratably over the remaining period of the arrangement. If the professional services are essential to the functionality of the subscription, then the revenue recognition does not commence until such services are completed.
	The Company's revenue arrangements typically include subscription services to its security-as-a-service platform. These hosted on demand service arrangements do not provide customers with the right to take possession of the software supporting the hosted services. Certain arrangements also include the sale of hardware appliances. Revenue from hardware appliances containing software components and hardware components that function together to deliver the hardware appliance's essential functionality is excluded from the scope of the industry specific revenue recognition guidance. The Company recognizes revenue from its hosted on demand services in accordance with general revenue recognition accounting guidance. Only revenue derived from the licensing of the software is recognized in accordance with the industry specific revenue guidance.
	When a sales arrangement contains multiple elements, such as hardware appliances, subscription services, customer
	support services, and/or professional services, the Company allocates revenue to each unit of accounting or element based on a selling price hierarchy. An element constitutes a separate unit of accounting when the delivered item has standalone value and delivery of the undelivered element is probable and within the Company's control. When applying the relative selling price method, the Company determines the selling price for each deliverable using vendor-specific objective evidence (“VSOE”) of selling price. If VSOE does not exist, the Company uses third-party evidence (“TPE”) of selling price. If neither VSOE nor TPE of selling price exist for a deliverable, the Company uses its best estimate of selling price ("BESP") for that deliverable. Revenue allocated to each element is then recognized when the basic revenue recognition criteria are met for each element. The Company determines BESP for an individual element within a multiple element revenue arrangement using the same methods utilized to determine the selling price of an element sold on a standalone basis. The Company estimates the selling price for its subscription solutions by considering internal factors such as historical pricing practices and it estimates the selling price of hardware and other services using a cost plus model.
	Hardware appliance revenue is recognized upon shipment. Subscription and support revenue are recognized over the contract period commencing on the start date of the contract. Professional services and training, when sold with hardware appliances or subscription and support services, are accounted for separately when those services have standalone value. In determining whether professional services and training services can be accounted for separately from subscription and support services, the Company considers the following factors: availability of the services from other vendors, the nature of the services, and the dependence of the subscription services on the customer’s decision to buy the professional services. If professional services and training do not qualify for separate accounting, the Company recognizes the professional services and training ratably over the contract term of the subscription services.
	Delivery generally occurs when the hardware appliance is delivered to a common carrier freight on board shipping point by the Company or the hosted service has been activated and communicated to the customer accordingly. The Company’s fees are typically considered to be fixed or determinable at the inception of an arrangement and are negotiated at the outset of an arrangement, generally based on specific products and quantities to be delivered. In the event payment terms are provided that differ significantly from the Company's standard business practices, the fees are deemed to not be fixed or determinable and revenue is recognized as the fees become paid.
	The Company assesses collectability based on a number of factors, including credit worthiness of the customer and past transaction history of the customer. Through December 31, 2014, the Company has not experienced material credit losses.
	Deferred Revenue
	Deferred revenue primarily consists of billings or payments received in advance of revenue recognition from the sale of the Company’s subscription fees, training and professional services. Once the revenue recognition criteria are met, this revenue is recognized ratably over the term of the associated contract.
	Deferred Product Costs
	Deferred product costs are the incremental costs that are directly associated with each noncancellable customer contract or hosting agreement and primarily consist of cost of appliances and royalty payments made to third parties, from whom the Company has obtained licenses to integrate certain software into its products. The costs are deferred and amortized over the noncancellable term of the related customer contract or hosting agreement, which typically range from 12 to 36 months.
	Property and Equipment
	Property and equipment are stated at cost. Depreciation is computed using the straight-line method over the estimated useful life of the related asset. Amortization of leasehold improvements is computed using the straight-line method over the shorter of the lease term or the estimated useful life of the asset or improvement. Cost of maintenance and repairs that do not improve or extend the lives of the respective assets are expensed as incurred. When property and equipment are retired or otherwise disposed of, the cost and related accumulated depreciation are removed from the balance sheet and the resulting gain or loss is included in other (expense) income, net.
	Impairment of Intangible Assets and Other Long-Lived Assets
	The Company evaluates long-lived assets, such as property and equipment, including intangible assets other than goodwill, for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Recoverability of these assets is measured by comparison of the carrying amount of such assets (or asset group) to the future undiscounted cash flows the assets (or asset group) is expected to generate. If the assets are considered to be impaired, the amount of any impairment is measured as the difference between the carrying value and the fair value of the impaired assets. The Company also evaluates the estimated remaining useful lives of intangible assets and other long-lived assets to assess whether a revision to the remaining periods of amortization is required. No assets were determined to be impaired to date.
	Advertising and Promotion Costs
	Expenses related to advertising and promotion of solutions is charged to sales and marketing expense as incurred. The Company did not incur any significant advertising and promotion expenses during the years ended December 31, 2014, 2013 and 2012.
	Goodwill and Intangible Assets
	Goodwill represents the excess of the purchase price of the acquired enterprise over the fair value of identifiable assets acquired and liabilities assumed. The Company performs an annual goodwill impairment test during the fourth quarter of the Company's fiscal year and more frequently if an event or circumstances indicates that impairment may have occurred. For the purposes of impairment testing, the Company has determined that it has one operating segment and one reporting unit. The Company performs a two-step impairment test of goodwill whereby the fair value of the reporting unit is compared to its carrying value. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that unit, goodwill is not considered impaired and further testing is not required. If the carrying value of the net assets assigned to the reporting unit exceeds the fair value of the reporting unit, then the Company must perform the second step of the impairment test in order to determine the implied fair value of the reporting unit’s goodwill. If the carrying value of a reporting unit’s goodwill exceeds its implied fair value, then impairment loss equal to the difference is recorded. The identification and measurement of goodwill impairment involves the estimation of the fair value of the Company. The estimate of fair value of the Company, based on the best information available as of the date of the assessment, is subjective and requires judgment, including management assumptions about expected future revenue forecasts and discount rates, changes in the overall economy, trends in the stock price and other factors. No impairment was identified by the Company as of December 31, 2014.
	Intangible assets consist of developed technology, customer relationships, non-compete arrangements, trademarks and patents, order backlog and in-process research and development asset. The values assigned to intangibles are based on estimates and judgments regarding expectations for success and life cycle of solutions and technologies acquired.
	Intangible assets are amortized on a straight-line basis over their estimated lives, which approximate the pattern in which the economic benefits of the intangible assets are consumed, as follows (in years):
		Low	High
	Patents	4	5
	Developed technology	3	7
	Customer relationships	2	7
	Non-compete agreements	2	4
	Order backlog	2	2
	Tradenames and trademarks	1	5
	In-process research and development asset is not amortized until the associated project is completed.
	Warranty
	The Company provides limited warranties on all sales and provides for the estimated cost of the warranties at the date of sale, to the extent not already provided by its own vendors. The estimated cost of warranties has not been material to date.
	Income Taxes
	The Company accounts for income taxes in accordance with authoritative guidance, which requires use of the asset and liability method. Under this method, deferred income tax assets and liabilities are determined based on the difference between the consolidated financial statements carrying amounts and the tax basis of assets and liabilities and are measured using the enacted tax rates expected to apply to taxable income in the years in which the differences are expected to be reversed.
	The Company records net deferred tax assets to the extent the Company believes these assets will more likely than not be realized. In making such determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax planning strategies and recent financial operations.
	The Company has elected to use the "with and without" approach as described in ASC 740-20, "Intraperiod Tax Allocation" in determining the order in which tax attributes are utilized. As a result, the Company will only recognize a tax benefit from stock-based awards in additional paid-in capital if an incremental tax benefit is realized after all other tax attributes currently available to the Company have been utilized. In addition, the Company has elected to account for the impact of stock-based awards on other tax attributes, such as the research tax credit, within the consolidated statements of operations.
	The Company recognizes interest and penalties related to uncertain tax positions within the income tax expense line in the consolidated statements of operations. Accrued interest and penalties are included within the related tax liability line on the consolidated balance sheets.
	Employee Benefit Plans
The Company sponsors a 401(k) defined contribution plan covering all employees. The Company may make discretionary contributions to the 401(k). To date, no contributions have been made by the Company.
Stock-Based Compensation
The Company issues stock-based compensation awards to employees and directors in the form of stock options, restricted stock units ("RSUs"), performance stock units ("PSUs") and employee stock purchase plan ("ESPP") awards (collectively, "awards").
The Company measures and recognizes compensation expense for all stock-based awards based on the awards' fair value. Stock-based compensation for RSUs and PSUs is measured based on the value of the Company's common stock on the grant date. Stock-based compensation for employee stock options and ESPP awards are measured on the date of grant using a Black-Scholes option pricing model.
Awards vest either on a graded schedule or in a lump sum. The Company determines the fair value of each award as a single award and recognizes the expense on a straight-line basis over the service period of the award, which is generally the vesting period. The exercise price of stock options granted is equal to the fair value of the Company's common stock on the date of grant. Stock options expire ten years from the date of grant.
Stock-based compensation expense for stock options, RSUs, PSUs and the ESPP is based on awards ultimately expected to vest, and the expense is recorded net of estimated forfeitures.
Comprehensive Income (Loss)
Comprehensive income (loss) includes all changes in equity that are not the result of transactions with stockholders. The Company’s comprehensive income (loss) consists of its net loss and changes in unrealized gains (losses) on its available-for-sale investments.
Loss Contingencies
The Company may be involved in various lawsuits, claims and proceedings that arise in the ordinary course of business. The Company records a provision for a liability when it believes that it is both probable that a liability has been incurred and the amount can be reasonably estimated. Significant judgment is required to determine both probability and the estimated amount. The Company reviews these provisions at least quarterly and adjusts these provisions to reflect the impact of negotiations, settlements, rulings, and updated information.
Recent Accounting Policies
In June 2014, the FASB issued ASU 2014-12, Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period, a new accounting standard update that clarifies the accounting for share-based payments when the terms of an award allow for a performance target to be achieved after an employee completes the requisite period. The amendments require that a performance target that affects vesting and that could be achieved after the requisite period be treated as a performance condition. A company should apply existing guidance in Topic 718 as it relates to awards with performance conditions that affect vesting to account for such awards. Compensation cost should be recognized in the period in which it becomes probable that the performance target will be achieved and should represent the compensation cost attribute to the period(s) for which the requisite service has already been rendered. The new guidance will become effective for the Company on January 1, 2016 with early adoption is permitted. The adoption of this guidance is not expected to have material impact on the Company's consolidated financial statements.
In May 2014, the FASB issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers: Topic 606 (ASU 2014-09), to supersede nearly all existing revenue recognition guidance under U.S. GAAP. The core principle of ASU 2014-09 is to recognize revenues when promised goods or services are transferred to customers in an amount that reflects the consideration that is expected to be received for those goods or services. ASU 2014-09 defines a five step process to achieve this core principle and, in doing so, it is possible more judgment and estimates may be required within the revenue recognition process than required under existing U.S. GAAP including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. ASU 2014-09 is effective for the Company starting January 1, 2017 using either of two methods: (i) retrospective to each prior reporting period presented with the option to elect certain practical expedients as defined within ASU 2014-09; or (ii) retrospective with the cumulative effect of initially applying ASU 2014-09 recognized at the date of initial application and providing certain additional disclosures as defined per ASU 2014-09. The Company is currently evaluating the impact of the adoption of ASU 2014-09 on its consolidated financial statements.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Acquisitions	Acquisitions
	In 2014 and 2013, the Company entered into agreements to acquire two and five companies (collectively, the "Acquisitions"), respectively. Each acquisition was accounted for under the purchase method of accounting in which the tangible and identifiable intangible assets and liabilities of each acquired company were recorded at their respective fair values as of each acquisition date, including an amount for goodwill representing the difference between the respective acquisition consideration and fair values of identifiable assets acquired and liabilities assumed. The Company believes the combined entities will achieve savings in corporate overhead costs and opportunities for growth through expanded geographic and customer segment diversity with the ability to leverage additional products and capabilities. These factors, among others, contributed to a purchase price in excess of the estimated fair value of each acquired company's net identifiable assets acquired and, as a result, goodwill was recorded in connection with each acquisition. Goodwill related to each acquisition, other than eDynamics LLC, is not deductible for tax purposes.
	For each of the acquisitions, the Company disclosed material revenue amounts in the acquisition year, but due to the continued integration of the combined businesses, it was impractical to determine the earnings.
	Nexgate, Inc.
	On October 31, 2014 (the "Nexgate Acquisition Date"), pursuant to the terms of an Agreement and Plan of Merger, a wholly-owned subsidiary of the Company merged with and into Nexgate, Inc. ("Nexgate"), with Nexgate surviving as a wholly-owned subsidiary of the Company. Formerly based in Burlingame, California, Nexgate provides cloud-based brand protection and compliance for enterprise social media accounts. With this acquisition, the Company's customers can effectively protect their online brand presence and social media communication infrastructure. Nexgate technology identifies and remediates fraudulent social media accounts, account hacks, and content that contains malware, spam and abusive language. In addition, the Nexgate solution enforces policy on authorized accounts and posts for compliance with a wide-range of social media regulatory requirements.
	The Company has provisionally estimated the fair values for the acquired tangible and identifiable intangible assets and liabilities assumed at the Nexgate Acquisition Date. The amounts reported were considered provisional as the Company was completing the valuation work to determine the fair value of certain assets acquired and liabilities assumed.
	The results of operations and the provisional fair values of the acquired assets and liabilities assumed have been included in the accompanying consolidated financial statements since the Nexgate Acquisition Date. Revenue from Nexgate was not material for the year ended December 31, 2014.
	At the Nexgate Acquisition Date, the Company paid $31,771 in cash consideration, net of cash acquired of $1,032. Of the cash consideration paid, $5,250 was held in escrow to secure indemnification obligations, which has not been released as of the filing date of this Annual Report on Form 10-K. The Company incurred $231 in acquisition-related costs which were recorded within operating expenses for the year ended December 31, 2014.
	Fair value of acquired assets and liabilities assumed
	The determination of the fair values of the assets acquired and liabilities assumed has been prepared on a provisional basis and changes to that determination may occur as additional information becomes available. The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
		Estimated			Estimated
		Fair Value in USD			Useful Life (in years)
	Current assets acquired	$	1,340		N/A
	Fixed assets acquired	15			N/A
	Liabilities assumed	(88		)	N/A
	Deferred revenue assumed	(600		)	N/A
	Customer relationships	3,000			7
	Order backlog	200			2
	Core/developed technology	3,200			4
	In-process research and development	900			N/A
	Deferred tax liability, net	(792		)	N/A
	Goodwill	25,628			Indefinite
		$	32,803
	NetCitadel, Inc.
	On May 13, 2014 (the "NetCitadel Acquisition Date"), pursuant to the terms of an Agreement and Plan of Merger, a wholly-owned subsidiary of the Company merged with and into NetCitadel, Inc. ("NetCitadel"), with NetCitadel surviving as a wholly-owned subsidiary of the Company. Formerly based in Mountain View, California, NetCitadel is a pioneer in the field of automated security incident response. The acquisition extends the reach and capabilities of the Company's existing advanced threat solutions, adding additional threat verification and containment capabilities via an open platform that unifies products from the Company and other vendors.
	The Company has provisionally estimated fair values for the acquired tangible and identifiable intangible assets and liabilities assumed at the NetCitadel Acquisition Date. The amounts reported were considered provisional as the Company was completing the valuation work to determine the fair value of certain assets acquired and liabilities assumed.
	The results of operations and the provisional fair values of the acquired assets and liabilities assumed have been included in the accompanying consolidated financial statements since the NetCitadel Acquisition Date. Revenue from NetCitadel was not material for the year ended December 31, 2014.
	At the NetCitadel Acquisition Date, the Company paid $22,731. Of the cash consideration paid, $3,369 was held in escrow to secure indemnification obligations, which has not been released as of the filing date of this Form 10-K. The Company incurred $345 in acquisition-related costs which were recorded within operating expenses for the year ended December 31, 2014.
	Fair value of acquired assets and liabilities assumed
	The determination of the fair values of the assets acquired and liabilities assumed has been prepared on a provisional basis and changes to that determination may occur as additional information becomes available. The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
		Estimated			Estimated
		Fair Value in USD			Useful Life
	Tangible assets acquired	$	14		N/A
	Liabilities assumed	(1,267		)	N/A
	Customer relationships	100			5
	Core/developed technology	5,500			5
	Goodwill	18,384			Indefinite
		$	22,731
	Sendmail, Inc.
	On October 1, 2013 (the "Sendmail Acquisition Date"), pursuant to the terms of an Agreement and Plan of Merger, a wholly-owned subsidiary of the Company merged with and into Sendmail, Inc. ("Sendmail"), with Sendmail surviving as a wholly-owned subsidiary of the Company. Formerly based in Emeryville, California, Sendmail is a leading provider of messaging infrastructure solutions to enterprises whose solutions ensure global email connectivity, routing and message delivery between people, systems and applications located on-premise, in-cloud or on mobile devices. The acquisition of Sendmail allows the Company access to its Sentrion Email Platform business, customers, core engineering and professional teams which have demonstrated a sustained level of expertise in messaging infrastructure.
	During the quarter ended December 31, 2013, the Company completed the valuation of the estimated fair values of the acquired tangible and identifiable intangible assets and liabilities assumed at the Sendmail Acquisition Date, and the results of operations and the fair values of the acquired assets and liabilities assumed have been included in the consolidated financial statements since the Sendmail Acquisition Date. The Company recorded 2,975 in revenue from Sendmail for the year ended December 31, 2013.
	At the Sendmail Acquisition Date, the Company paid $12,463 in cash consideration, net of cash acquired of $1,117. Of the cash consideration paid, $3,422 was held in escrow to secure indemnification obligations, of which $719 was recovered from indemnification claims in 2014. As part of the acquisition, the Company assumed and paid off $7,933 in long-term debt on the Sendmail Acquisition Date. The Company incurred $1,877 in acquisition-related costs which were recorded within operating expenses for the year ended December 31, 2013.
	Fair value of acquired assets and liabilities assumed
	The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
		Fair Value in USD			Estimated
					Useful Life (in years)
	Tangible assets acquired	$	5,202		N/A
	Liabilities assumed	(5,162		)	N/A
	Deferred revenue assumed	(14,549		)	N/A
	Long-term debt assumed	(7,933		)	N/A
	Trade name	400			5
	Customer relationships	8,000			3
	Patents	300			5
	Core/developed technology	3,000			3
	Goodwill	24,322			Indefinite
		$	13,580
	Armorize Technologies, Inc.
	On September 5, 2013 (the "Armorize Acquisition Date"), pursuant to the terms of an Agreement and Plan of Merger, a wholly-owned subsidiary of the Company merged with and into Armorize Technologies, Inc. ("Armorize"), with Armorize surviving as a wholly-owned subsidiary of the Company. Based in Taiwan, Armorize develops and markets leading cloud-based SaaS anti-malware products and will add real-time dynamic detection of next generation threats and malware to the Company's existing capabilities.
	During the quarter ended September 30, 2013, the Company completed the valuation of the estimated fair values of the acquired tangible and identifiable intangible assets and liabilities assumed at the Armorize Acquisition Date, and the results of operations and the fair values of the acquired assets and liabilities assumed have been included in the consolidated financial statements since the Armorize Acquisition Date. The Company recorded $781 in revenue from Armorize for the year ended December 31, 2013.
	At the Armorize Acquisition Date, the Company paid $24,215 in cash consideration, net of cash acquired of $1,746. Of the cash consideration paid, $3,750 was held in escrow to secure indemnification obligations, which has not been released as of the filing date of this Annual Report on Form 10-K. The Company incurred $747 in acquisition-related costs which were recorded within operating expenses for the year ended December 31, 2013.
	Fair value of acquired assets and liabilities assumed
	The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
		Fair Value in USD			Estimated
					Useful Life (in years)
Tangible assets acquired	$	2,754		N/A
Liabilities assumed	(1,234		)	N/A
Customer relationships	1,300			2
Non-compete agreements	500			3
Core/developed technology	3,850			5
Goodwill	18,791			Indefinite
	$	25,961
Abaca Technology Corporation
On July 19, 2013 (the "Abaca Technology Acquisition Date"), pursuant to the terms of an Agreement and Plan of Merger, a wholly-owned subsidiary of the Company merged with and into Abaca Technology Corporation ("Abaca Technology"), with Abaca Technology surviving as a wholly-owned subsidiary of the Company. Abaca Technology specializes in email filtering and protection algorithms and their cloud-based, in-memory threat scoring technologies are expected to complement the Company's continued investment in anti-spam and threat detection capabilities.
During the quarter ended September 30, 2013, the Company completed the valuation of the estimated fair values of the acquired tangible and identifiable intangible assets and liabilities at the Abaca Technology Acquisition Date, and the results of operations and the fair values of the acquired assets and liabilities assumed have been included in the consolidated financial statements since the Abaca Technology Acquisition Date. The Company recorded $311 in revenue from Abaca Technology for the year ended December 31, 2013.
At the Abaca Technology Acquisition Date, the Company paid $23 in cash consideration, net of cash acquired of $3. The purchase consideration included an additional amount of $1,520 which was held back to secure contingent liabilities related to indemnification obligations. The initial fair values of the contingent liabilities of $1,397 were recorded in other long-term liabilities in the consolidated balance sheet. The indemnification obligations have not been released as of the filing date of this Annual Report on Form 10-K. The Company incurred $218 in acquisition-related costs which were recorded within operating expenses for the year ended December 31, 2013.
Fair value of acquired assets and liabilities assumed
The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
	Fair Value in USD			Estimated
				Useful Life (in years)
Tangible assets acquired	$	311		N/A
Liabilities assumed	(962		)	N/A
Customer relationships	40			3
Core/developed technology	1,770			5
Goodwill	264			Indefinite
	$	1,423
eDynamics, LLC
On July 10, 2013 (the "eDynamics Acquisition Date"), pursuant to the terms of an Asset Purchase Agreement. the Company purchased substantially all of the business intellectual property and assumed certain liabilities of eDynamics, LLC ("eDynamics"). eDynamics is a social media archiving company and is expected to be an integral part of the Company's broader effort in rolling out a comprehensive social media archiving platform for customers.
During the quarter ended September 30, 2013, the Company completed the valuation of the estimated fair values of the acquired tangible and identifiable intangible assets and liabilities assumed at the eDynamics Acquisition Date, and the results of operations and the fair values of the acquired assets and liabilities assumed have been included in the consolidated financial statements since the eDynamics Acquisition Date. Revenue from eDynamics was not material for the year ended December 31, 2013.
At the eDynamics Acquisition Date, the Company paid $500 in cash consideration. The Company also agreed to pay earn-out consideration ("Acquisition-related contingent earn-out liability") of up to $600 through April 2014, such liability being contingent upon the achievement of specified product development milestones. The initial fair value of the contingent earn-out liability of $586 was recorded as part of the purchase consideration. The purchase consideration also included an additional amount of $100, which was held back to secure any claims that may arise in the 12-month period after the eDynamics Acquisition Date. The initial fair value of such amount withheld of $72 as well as the Acquisition-related contingent earn-out liability were recorded in accrued liabilities on the consolidated balance sheet. The Company paid $100 of the contingent earn-out liability during the year ended December 31, 2013, the remaining earn-out consideration and holdback amount were paid in full in year ended December 31, 2014. The Company incurred $6 in acquisition-related costs which were recorded within operating expenses for the year ended December 31, 2013.
Fair value of acquired assets and liabilities assumed
The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
	Fair Value in USD			Estimated
				Useful Life (in years)
Customer relationships	$	243		3.5
Non-compete agreements	75			2
Core/developed technology	733			3.5
Goodwill	107			Indefinite
	$	1,158
Mail Distiller Limited
On April 5, 2013 (the "Mail Distiller Acquisition Date"), pursuant to the terms of a share transfer agreement, the Company purchased all of the outstanding share capital of Mail Distiller Limited, a Northern Ireland Company ("Mail Distiller"). Mail Distiller is a European-based provider of the SaaS email security solutions. Mail Distiller allowed the Company to create the Proofpoint Essentials product line, a suite of SaaS security and compliance solutions specifically designed for distribution across managed service providers and dedicated security resellers.
During the quarter ended June 30, 2013, the Company completed the valuation of the estimated fair values of the acquired tangible and identifiable intangible assets and liabilities assumed at the Mail Distiller Acquisition Date, and the results of operations and the fair values of the acquired assets and liabilities assumed have been included in the consolidated financial statements since the Mail Distiller Acquisition Date. The Company recognized $216 in revenue from Mail Distiller for the year ended December 31, 2013.
At the Mail Distiller Acquisition Date, the Company paid $3,771 in cash consideration, net of cash acquired of $60. The purchase consideration included an additional amount of $669 held back to secure indemnification obligations, which was recorded in accrued liabilities on the consolidated balance sheet as of December 31, 2013. The indemnification obligations has been released in year ended December 31, 2014. The Company incurred $258 in acquisition-related costs which were recorded within operating expenses for the year ended December 31, 2013.
Fair value of acquired assets and liabilities assumed
The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
	Fair Value in USD			Estimated
				Useful Life (in years)
Tangible assets acquired	$	204		N/A
Liabilities assumed	(1,052		)	N/A
Trade name	7			1
Customer relationships	1,291			2
Non-compete agreements	123			2
Core/developed technology	2,475			7
Goodwill	1,452			Indefinite
	$	4,500
Pro Forma Financial Information
The following unaudited pro forma financial information presents the combined results of operations for the years ended December 31, 2014, 2013 and 2012 as though the acquisitions that occurred during the reporting periods had occurred as of the beginning of the comparable prior annual reporting periods, with adjustments to give effect to pro forma events that are directly attributable to the acquisitions such as amortization expense of acquired intangible assets, stock-based compensation directly attributable to the acquisitions and acquisition-related transaction costs. The unaudited pro forma results do not reflect any operating efficiencies or potential cost savings which may result from the consolidation of the operations of the Company and acquisitions. Accordingly, these unaudited pro formas results are presented for informational purposes only and are not necessarily indicative of what the actual results of operations of the combined company would have been if the acquisitions had occurred at the beginning of the period presented, nor are they indicative of future results of operations:
	Twelve Months Ended December 31,
	2014				2013			2012
Total revenue	$	196,701			$	166,577		$	150,934
Net loss	(70,871		)		(46,090		)	(28,229		)
Basic and diluted net loss per share	$	(1.90	)		$	(1.32	)	$	(1.17	)
The unaudited pro forma financial information includes acquisition-related transaction costs of $576 for the year ended year ended December 31, 2014.

Concentration_of_Risks

Concentration of Risks	12 Months Ended
	Dec. 31, 2014
Risks and Uncertainties [Abstract]
Concentration of Risks	Concentration of Risks
	Financial instruments that potentially subject the Company to credit risk consist principally of cash and cash equivalents, short-term investments and accounts receivable.
	The Company limits its concentration of risk in cash equivalents and short-term investments by diversifying its investments among a variety of industries and issuers and by limiting the average maturity to one year or less. The Company's professional portfolio managers adhere to this investment policy as approved by the Company's Board of Directors.
	The Company's investment policy is to invest only in fixed income investments denominated and payable in U.S. dollars. Investment in obligations of the U.S. government and its agencies, money market instruments, commercial paper, certificates of deposit, bankers' acceptances, corporate bonds of U.S. companies, municipal securities and asset backed securities are allowed. The Company does not invest in auction rate securities, futures contracts, or hedging instruments.
	The Company's accounts receivables are derived from revenue earned from customers primarily located in the United States of America. The Company performs periodic evaluations of its customers' financial condition and generally does not require its customers to provide collateral or other security to support accounts receivable, and maintains an allowance for doubtful accounts. Credit losses historically have not been significant.
	During the year ended December 31, 2014, one customer accounted for 12% of total revenue. One customer accounted for 14% of total revenue in the years ended December 31, 2013 and 2012.
	At years ended December 31, 2014 and 2013, there were no customers that accounted for more than 10% of total accounts receivable.

Balance_Sheet_Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Components	Balance Sheet Components
	Allowance for doubtful accounts activity and balances are presented below:
		Balance at				Additions				Write			Balance at
		Beginning of				to Costs and				Offs			End of
		Period				Expenses							Period
	Year ended December 31, 2012	$	233			$	54			$	(100	)	$	187
	Year ended December 31, 2013	$	187			$	91			$	(2	)	$	276
	Year ended December 31, 2014	$	276			$	158			$	(5	)	$	429
	Property and equipment at December 31, 2014 and 2013 consist of the following:
		Useful Life		December 31,
		(in years)		2014				2013
	Computer equipment	2 to 3		$	42,933			$	31,305
	Software	2		1,850				1,782
	Furniture	5		170				76
	Office equipment	2 to 5		582				397
	Leasehold improvements	5 years, or lease term, if shorter		4,341				1,298
	Other	2		59				59
	Construction in progress			643				339
				50,578				35,256
	Less: Accumulated depreciation			(31,860		)		(24,035		)
				$	18,718			$	11,221
	Property and equipment acquired under capital leases:
		December 31,
		2014				2013
	Computer equipment	$	346			$	346
	Less: Accumulated depreciation	(336		)		(317		)
		$	10			$	29
	Depreciation expense for the years ended December 31, 2014, 2013 and 2012, was approximately $9,033, $5,923, and $4,434, respectively. This included depreciation expense for assets under capital leases of $19, $48 and $42 for the years ended December 31, 2014, 2013 and 2012, respectively.
	The Company capitalized software development costs of $400 in the year ended December 31, 2011. Amortization of capitalized software development costs was approximately $159 and $200 for the years ended December 31, 2013 and 2012, respectively. Capitalized software development costs were fully amortized as of December 31, 2014 and 2013.
	Accrued liabilities at December 31, 2014 and 2013 consisted of the following:
		December 31,
		2014				2013
	Accrued compensation	$	15,206			$	8,886
	Customer deposits	1,484				2,098
	Accrued royalties	706				766
	Other	6,824				7,510
		$	24,220			$	19,260

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets
	The goodwill activity and balances are presented below:
		December 31,
		2014			2013
	Opening balance	$	63,764		$	18,557
	Add: Goodwill from acquisitions	44,015			45,207
	Less: Other adjustments to Goodwill	(275		)	—
	Closing balance	$	107,504		$	63,764
	The goodwill balance as of December 31, 2014 was the result of the acquisitions of Fortiva, Inc., Secure Data in Motion, Inc., Everyone.net, Inc., Spam and Open Relay Blocking System from GFI Software Ltd., NextPage, Inc., Mail Distiller, eDynamics, Abaca, Armorize, Sendmail and the Acquisitions completed during the year ended December 31, 2014 (see Note 2, "Acquisitions").
	Intangible Assets
	Intangible assets excluding goodwill consisted of the following:
		31-Dec-14								31-Dec-13
		Gross			Accumulated			Net		Gross		Accumulated			Net
		Carrying			Amortization			Carrying		Carrying		Amortization			Carrying
		Amount						Amount		Amount					Amount
	Developed technology	$	38,168		$	(21,538	)	$	16,630	$	29,468	$	(17,383	)	$	12,085
	Customer relationships	16,382			(7,893		)	8,489		13,282		(3,726		)	9,556
	Non-compete agreements	804			(462		)	342		804		(170		)	634
	Trademark and patents	806			(264		)	542		806		(105		)	701
	Order backlog	200			(17		)	183		—		—			—
	In-process research and development	900			—			900		—		—			—
		$	57,260		$	(30,174	)	$	27,086	$	44,360	$	(21,384	)	$	22,976
	Amortization expense of intangibles totaled $8,790, $4,044 and $3,276 during the years ended December 31, 2014, 2013 and 2012, respectively.
	Future estimated amortization costs of intangible assets as of December 31, 2014 are presented below:
	Year Ended December 31,
	2015	$	9,717
	2016	7,424
	2017	4,195
	2018	3,616
	2019	1,252
	Thereafter	882
		$	27,086

Fair_Value_Measurements_and_In

Fair Value Measurements and Investments	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements and Investments	Fair Value Measurements and Investments
	Fair Value Measurements
	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (i.e., the “exit price”) in an orderly transaction between market participants at the measurement date. A hierarchy for inputs used in measuring fair value has been defined to minimize the use of unobservable inputs by requiring the use of observable market data when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on active market data. Unobservable inputs are inputs that reflect the Company’s assumptions about the assumptions market participants would use in pricing the asset or liability based on the best information available in the circumstances.
	The fair value hierarchy prioritizes the inputs into three broad levels:
	•	Level 1: Quoted (unadjusted) prices in active markets for identical assets or liabilities.
	The Company’s Level 1 assets generally consist of money market funds.
	•	Level 2: Observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar assets or liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the asset or liability.
	The Company’s Level 2 assets and liabilities generally consist of corporate debt securities, commercial papers, certificates of deposit and convertible senior notes.
	•	Level 3: Unobservable inputs to the valuation methodology that are supported by little or no market activity and that are significant to the measurement of the fair value of the assets or liabilities. Level 3 assets and liabilities include those whose fair value measurements are determined using pricing models, discounted cash flow methodologies or similar valuation techniques, as well as significant management judgment or estimation.
	In connection with the acquisition of eDynamics in 2013, a liability was recognized on the eDynamics Acquisition Date for the estimate of the fair value of the Company's contingent earn-out payments related to eDynamics. The Company determined the fair value of the Acquisition-related contingent earn-out liability based on the probability-based attainment of product development milestones. The fair value measurements were based on significant inputs not observable in the market and thus represent Level 3 measurements, which reflected the Company's own assumptions concerning achievement of the product development milestones of eDynamics, in measuring the fair value of the contingent earn-out liability related to the acquisition of eDynamics. This contingent earn-out liability was extinguished during the year-ended December 31, 2014.
	The following tables summarize, for each category of assets or liabilities carried at fair value, the respective fair value as of December 31, 2014 and 2013 and the classification by level of input within the fair value hierarchy:
		Balance as of				Quoted Prices		Significant			Unobservable
		December 31,				in Active		Other			Inputs
		2014				Markets for		Observable			(Level 3)
						Identical		Inputs
						Assets		(Level 2)
						(Level 1)
	Assets
	Cash equivalents:
	Money market funds	$	139,644			$	139,644	$	—		$	—
	Short-term investments:
	Corporate debt securities	31,651				—		31,651			—
	Commercial papers	2,998				—		2,998			—
	Total financial assets	$	174,293			$	139,644	$	34,649		$	—
		Balance as of				Quoted Prices		Significant			Unobservable
		December 31,				in Active		Other			Inputs
		2013				Markets for		Observable			(Level 3)
						Identical		Inputs
						Assets		(Level 2)
						(Level 1)
	Assets
	Cash equivalents:
	Money market funds	$	215,094			$	215,094	$	—		$	—
	Short-term investments:
	Corporate debt securities	6,015				—		6,015			—
	Certificates of deposit	2,000				—		2,000			—
	Total financial assets	$	223,109			$	215,094	$	8,015		$	—
	Liabilities
	Acquisition-related contingent earn-out liability	$	495			$	—	$	—		$	495
	Based on quoted market prices as of December 31, 2014, the fair value of the Senior Convertible Notes (Note 8) was approximately $277,725, determined using Level 2 inputs as they are not actively traded in markets.
	The following table represents a reconciliation of the Acquisition-related contingent earn-out liability measured at fair value on a recurring basis, using significant unobservable inputs (Level 3) for the year ended December 31, 2014:
			Fair Value Measurements Using Significant Unobservable Inputs
			(Level 3)
	Balance at December 31, 2013		$	495
	Payments during the period		(500		)
	Adjustments to fair value during the period recorded in General and Administrative expenses		5
	Balance at December 31, 2014		$	—
	The carrying amounts of the Company's cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate their fair values due to their short maturities. Based on borrowing rates that are available to the Company for loans with similar terms and consideration of the Company's credit risk, the carrying value of the notes payable approximates their fair values using Level 2 inputs.
	Investments
	The cost and fair value of the Company’s cash and available-for-sale investments as of December 31, 2014 and 2013 were as follows:
		December 31, 2014
		Amortized Cost				Unrealized		Unrealized			Fair
						Gains		Losses			Value
	Cash and cash equivalents:
	Cash	$	40,693			$	—	$	—		$	40,693
	Money market funds	139,644				—		—			139,644
	Total	$	180,337			$	—	$	—		$	180,337
	Short-term investments:
	Corporate debt securities	$	31,678			$	—	$	(27	)	$	31,651
	Commercial paper	2,998				—		—			2,998
	Total	$	34,676			$	—	$	(27	)	$	34,649
		December 31, 2013
		Amortized Cost				Unrealized		Unrealized			Fair
						Gains		Losses			Value
Cash and cash equivalents:
Cash	$	28,692			$	—	$	—		$	28,692
Money market funds	215,094				—		—			215,094
Total	$	243,786			$	—	$	—		$	243,786
Short-term investments:
Corporate debt securities	$	6,015			$	—	$	—		$	6,015
Certificate of deposit	2,000				—		—			2,000
Total	$	8,015			$	—	$	—		$	8,015
As of December 31, 2014 and 2013, all investments mature in less than one year. Estimated fair values for marketable securities are based on quoted market prices for the same or similar instruments.
The Company reviews its investments on a quarterly basis to identify and evaluate investments that have an indication of possible impairment and has determined that no other-than-temporary impairments associated with credit losses were required to be recognized during the year ended December 31, 2014.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Operating Leases
	The Company leases certain of its facilities under noncancellable operating leases with various expiration dates through February 2020.
	Premises rent expense was $3,283, $1,774 and $1,520 for the years ended December 31, 2014, 2013 and 2012, respectively.
	Capital Leases
	In July 2012, the Company entered into two lease agreements to lease certain office equipment with expiration dates in July and October 2015. The leases bear an annual interest rate of 4.50% and are secured by fixed assets used in the Company's office locations.
	At December 31, 2014, future annual minimum lease payments under noncancellable operating and capital leases were as follows:
		Capital			Operating
		Leases			Leases
	2015	$	11		$	7,961
	2016	—			6,949
	2017	—			3,762
	2018	—			3,628
	2019	—			3,515
	Thereafter	—			125
	Total minimum lease payments	11			$	25,940
	Less: Amount representing interest	—
	Present value of capital lease obligations	11
	Less: Current portion	(11		)
	Long-term portion of capital lease obligations	$	—
	Contingencies
	Under the indemnification provisions of the Company's customer agreements, the Company agrees to indemnify and defend and hold harmless its customers against, among other things, infringement of any patent, trademark or copyright under any country's laws or the misappropriation of any trade secret arising from the customers' legal use of the Company's solutions. The exposure to the Company under these indemnification provisions is generally limited to the total amount paid by the customers under the applicable customer agreement. However, certain indemnification provisions potentially expose the Company to losses in excess of the aggregate amount paid to the Company by the customer under the applicable customer agreement. To date, there have been no claims against the Company or its customers pursuant to these indemnification provisions.
	Legal Contingencies
	From time to time, the Company may be involved in legal proceedings and subject to claims in the ordinary course of business. On December 16, 2013, Finjan, Inc. sued the Company and its wholly-owned subsidiary, Armorize Technologies, Inc., in the United States District Court, Northern District of California for alleged patent infringement of a variety of its patents, demanding preliminary and permanent injunctive relief, and unspecified damages. The Company and Armorize filed an answer to the complaint on February 10, 2014. On April 15, 2014, Finjan’s initial disclosures in the lawsuit alleged approximately $13,500 in damages, but provide no basis or facts in support of this sum. On June 12, 2014, at the mandatory case management conference, the court ordered that the claims construction hearing be held in May 2015 and trial be set for January 2016, subject to later adjustment or delay. On November 14, 2014 by court order the court scheduled a summary judgment hearing for December 2015 and moved the trial date to March 2016. Based on the early stage of the claims and evaluation of the facts available at this time, the amount or range of reasonable possible losses to which the Company or Armorize is exposed cannot be estimated and the ultimate resolution of this matter and the associated financial impact, if any, remains uncertain at this time. The Company and Armorize intend to vigorously defend the lawsuit. Intellectual property litigation is subject to inherent uncertainties, and there can be no assurance that the expenses associated with defending any litigation or the resolution of this dispute would not have a material adverse impact on the Company's results of operations or cash flows. Regardless of the outcome, such proceedings and claims can have an adverse impact on the Company because of defense and settlement costs, diversion of resources and other factors, and there can be no assurances that favorable outcomes will be obtained.

Convertible_Senior_Notes

Convertible Senior Notes	12 Months Ended
	Dec. 31, 2014
Senior Notes [Abstract]
Convertible Senior Notes	Convertible Senior Notes
	On December 11, 2013, the Company issued $175,000 principal amount of 1.25% Convertible Senior Notes (the "Notes") due 2018 in a private offering to qualified institutional buyers ("Holders") pursuant to Rule 144A under the Securities Act of 1944 (the "Exchange Act"), as amended. The initial Holders of the Notes also had an option to purchase an additional$26,250 in principal amount which was exercised in full. The net proceeds after discount and issuance costs of $5,803 from the Notes offering were approximately $195,446. The Company uses the net proceeds for working capital and general corporate purposes, which may include funding the Company's operations, capital expenditures, potential acquisitions of businesses, products or technologies believed to be of strategic importance. The Notes bear interest at 1.25% per year, payable semi-annually in arrears every June 15 and December 15, beginning on June 15, 2014.
	The Notes are unsecured and rank senior in right of payment to any indebtedness expressly subordinated in right of payment to the Notes. They rank equally with the Company's other existing and future unsecured indebtedness that is not subordinated and are structurally subordinated to any current or future secured indebtedness to the extent of the value of the assets securing the indebtedness and other liabilities of the Company's subsidiaries.
	The initial conversion rate is 25.6271 shares of the Company’s common stock per $1 principal amount of notes which equates to 5,158 shares of common stock, or a conversion price equivalent of $39.02 per share of common stock. Throughout the term of the Notes, the conversion rate may be adjusted upon the occurrence of certain events. The Notes mature on December 15, 2018, unless repurchased, redeemed or converted in accordance with their terms prior to such date.
	At the Company's option, on or after December 20, 2016, the Company will be able redeem all or a portion of the Notes at 100% of the principal amount, plus any accrued and unpaid interest, under certain conditions. The Company may redeem the Notes in shares of the Company’s common stock, cash, or some combination of each.
	Prior to June 15, 2018, the Notes will be convertible at the option of the Holders only upon the satisfaction of certain conditions and during certain periods if any of the following events occur:
	•	during the calendar quarter commencing after March 31, 2014, if the last reported sale price of the Company's common stock is greater than or equal to 130% of the applicable conversion price on each such trading day for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on the last trading day of the preceding calendar quarter;
	•	during the 5 business day period after any 5 consecutive trading day period in which the trading price, as defined, per $1 principal amount of Notes for each trading day of such measurement period was less than 98% of the product of the last reported sale price of the Company's common stock and the applicable conversion rate on each such trading day;
	•	upon a notice of redemption by the Company; or
	•	upon the occurrence of specified corporate transactions.
	Subsequent to June 15, 2018, Holders may convert their Notes at the applicable conversion rate at any time prior to the close of business on the second scheduled trading day immediately preceding the maturity date.
	Holders of the Notes also have the right to require the Company to repurchase all or a portion of the Notes at 100% of the principal amount, plus accrued and unpaid special interest, if any, upon the occurrence of certain fundamental changes to the Company.
	In accordance with the authoritative accounting guidance, the Company allocated the total amount of the Notes into liability and equity components. The carrying value of the liability component at issuance was calculated as the present value of its cash flows using a discount rate of 6.5% based on the a blended rate between the yield rate for a Moody's B1-rating and the average debt rate for comparable convertible transactions from similar companies. The difference between the Notes principal and the carrying value of the liability component, representing the value of conversion premium assigned to the equity component, was recorded as an increase to additional paid in capital and as a debt discount on the issuance date. The equity component is being accreted using the effective interest rate method over the period from the issuance date through December 15, 2018 as a non-cash charge to interest expense. The amount recorded to additional paid in capital is not remeasured as long as it continues to meet the conditions for equity classification. Upon issuance of the Notes, the Company recorded $156,672 as debt and $44,578 as additional paid in capital within stockholders' equity.
	Additionally, the Notes holders' discount and issuance costs were bifurcated into debt issuance costs (attributable to the liability component) and equity issuance costs (attributable to the equity component) based on their relative fair values. The debt issuance costs were capitalized and recorded as deferred offering costs in other noncurrent assets and are being amortized to interest expense using the effective interest rate method from the issuance date through December 15, 2018. The equity issuance costs were recorded as a decrease to additional paid-in capital at the issuance date.
	At December 31, 2014, the net carrying amount of the liability component of the Notes consists of:
	Liability component:
	Principal	$	201,250
	Less: debt discount, net of amortization	(39,620		)
	Net carrying amount	$	161,630
	Equity component (1)	$	43,293
	(1) Recorded in the consolidated balance sheets as additional paid-in capital, net of the $1,285 issuance costs in equity
	For the years ended December 31, 2014 and 2013, the Company incurred the interest expense related to the Notes:
		2014			2013
	1.25% coupon	$	2,511		$	138
	Amortization of debt discount	8,702			486
	Amortization of debt issuance costs	51			3
	Total	$	11,264		$	627

Debt

Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt	Debt
	Equipment Financing Loans
	The Company entered into an equipment loan agreement with Silicon Valley Bank in April 2011 for an aggregate loan principal amount of $6,000. Interest on the advances is equal to prime rate plus 0.50%. As of December 31, 2014, the interest on the outstanding advances was 4.50%. The Company had the ability to draw down on this equipment line through April 19, 2012. Each drawn amount is due 48 months after funding. Borrowings outstanding under the equipment loan at December 31, 2014 were $684 payable in 2015. Equipment financed under this loan arrangement is collateralized by the respective assets underlying the loan. The terms of the loan restrict the Company’s ability to pay dividends. The loan includes a covenant that requires the Company to maintain cash and cash equivalents plus net accounts receivable of at least two times the amount of all outstanding indebtedness, excluding the impact from the Notes. As of December 31, 2014 the Company was in compliance with the covenant.
	Interest expense for equipment financing loans for the years ended December 31, 2014, 2013 and 2012 was $65, $140 and $211, respectively.

Common_Stock

Common Stock	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Common Stock	Common Stock
	Initial Public Offering
	In April 2012, the Company completed its initial public offering of its common stock to the public (“IPO”) whereby 5,859 shares of common stock sold by the Company (inclusive of 729 shares of common stock from the partial exercise of the overallotment option granted to the underwriters) and 1,370 shares of common stock sold by the selling shareholders (inclusive of 171 shares of common stock from the partial exercise of the overallotment option granted to the underwriters). The public offering price of the shares sold in the offering was $13.00 per share. The Company did not receive any proceeds from the sales of shares by the selling stockholders. The total gross proceeds from the offering to the Company were $76,200. After deducting underwriters’ discounts and commissions and offering expenses, the aggregate net proceeds received by the Company totaled approximately $68,300. Immediately prior to the closing of the IPO, all shares of the Company’s outstanding redeemable convertible preferred stock automatically converted into 19,567 shares of common stock. As a result, following the IPO, the Company has two classes of authorized stock: common stock and preferred stock.
	As of December 31, 2014, the Company is authorized to issue two classes of stock totaling 205,000 shares, of which 5,000 are designated as preferred stock and 200,000 are designated common stock, each with a par value of $0.0001 per share.
	On March 30, 2012, the Company's Board of Directors approved a 1-for-2 reverse stock split of the Company's common stock. The reverse stock split became effective on April 2, 2012. All of the share numbers, share prices, and exercise prices have been retrospectively adjusted to reflect the reverse stock split.
	Number of shares of common stock reserved for future issuance was as follows:
		December 31,
		2014	2013
	Shares available for future grant under the stock plans	4,330	4,584
	Options outstanding under stock plans	5,288	7,223
	Shares available for future issuance under ESPP	926	759
	Common stock issuable upon exercise of warrant and settlement of outstanding restricted stock units	2,934	1,216
	Common stock issuable upon conversion of the convertible senior notes	5,158	5,158
	Total shares reserved	18,636	18,940

Stock_Option_Plans

Stock Option Plans	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option Plans	Stock Option Plans
	Stock-Based Compensation Plans
	On March 30, 2012, the Board of Directors and the Company’s stockholders approved the 2012 Equity Incentive Plan (the "2012 Plan"), which became effective in April 2012. The Company has two equity incentive plans: the Company’s 2002 stock option plan (the “2002 Plan”) and the 2012 Plan. Upon the IPO, all shares that were reserved under the 2002 Plan but not issued, and shares issued but subsequently returned to the plan through forfeitures, cancellations and repurchases became part of the 2012 Plan and no further shares will be granted pursuant to the 2002 Plan. All outstanding stock awards under the 2002 and 2012 Plans will continue to be governed by their existing terms. Under the 2012 Plan, the Company has the ability to issue incentive stock options (“ISOs”), nonstatutory stock options (“NSOs”), restricted stock awards, stock bonus awards, stock appreciation rights ("SARs"), restricted stock units, and performance shares. The 2012 Plan also allows direct issuance of common stock to employees, outside directors and consultants at prices equal to the fair market value at the date of grant of options or issuance of common stock. Additionally, the 2012 Plan provides for the grant of performance cash awards to employees, directors and consultants. The Company has the right to repurchase any unvested shares (at the option exercise price) of common stock issued directly or under option exercises. The right of repurchase generally expires over the vesting period.
	Stock bonus awards are accounted for as liability-classified awards, because the obligations are based predominantly on fixed monetary amounts that are generally known at the inception of the obligation, to be settled with a variable number of shares of the Company's common stock.
	Under the 2002 and 2012 Plans, the term of an option grant shall not exceed ten years from the date of its grant and options generally vest over a three to four-year period, with vesting on a monthly or annual interval. Under the 2012 Plan, 20,316 shares of common stock are reserved for issuance to eligible participants. As of December 31, 2014, 4,330 shares were available for future grant. Restricted stock awards generally vest over a four-year period. The number of shares available for grant and issuance under the 2012 Plan will be increased automatically on each January 1 of 2013 through 2016 by an amount equal to 5% of the Company's shares outstanding on the immediately preceding December 31, but not to exceed 3,724 shares, unless the Board of Directors, in its discretion, determines to make a smaller increase.
	Stock Options
	The fair value of options granted is estimated on the grant date using the Black-Scholes option valuation model. This valuation model for stock-based compensation expense requires the Company to make assumptions and judgments about the variables used in the calculation, including the expected term (weighted-average period of time that the options granted are expected to be outstanding), the volatility of the common stock price and the assumed risk-free interest rate. The Company recognizes stock-based compensation expense for only those shares expected to vest over the requisite service period of the award. The Company determines its estimated forfeiture rate based on an analysis of its actual forfeitures and will continue to evaluate the appropriateness of the forfeiture rate based on recent forfeiture activity and expected future employee turnover, if any. Changes in the estimated forfeiture rate can have a significant effect on reported stock-based compensation expense, as the cumulative effect of adjusting the rate for all expense is recognized in the period the forfeiture estimate is changed. No compensation cost is recorded for options that do not vest and the compensation cost from vested options, whether forfeited or not, is not reversed.
	Prior to the Company's IPO, the Board of Directors, in good faith, determined the fair market values of the Company's common stock, based on the best information available to the Board and the Company's management at the time of grant. The Company performed its analysis in accordance with applicable elements of the practice aid issued by the American Institute of Certified Public Accountants entitled Valuation of Privately Held Company Equity Securities Issued as Compensation. The procedures performed to determine the fair value of the Company's common stock were based on a probability‑weighted expected return method to estimate the aggregate equity value of the Company.
	The weighted average fair value of stock options granted to employees during the years ended December 31, 2014, 2013 and 2012, was $20.25, $9.50 and $5.65, respectively. The fair values were estimated on the grant dates using the Black-Scholes option-pricing model with the following weighted-average assumptions:
		Year Ended December 31,
		2014		2013		2012
	Expected life (in years)	5.31-6.08		5.31 - 6.08		5.50 - 6.08
	Volatility	54% - 58%		57% - 61%		59% - 60%
	Risk-free interest rate	1.79% - 1.93%		0.9% - 1.8%		0.9% - 1.2%
	Dividend yield	—%		—%		—%
	The estimate for expected life of options granted reflects the midpoint of the vesting term and the contractual life computed utilizing the simplified method as allowed by the SEC staff. The Company does not have significant historical share option exercise experience and hence considers the expected term assumption calculated using the simplified method to be reasonable. Since the Company's stock has been publicly traded for a limited time, the stock volatility assumptions represent an estimate of the historical volatilities of the common stock of a group of publicly-traded peer companies that operate in a similar industry. The estimate was determined based on the average historical volatilities of these peer companies. The risk-free interest rate used was the Federal Reserve Bank's constant maturities interest rate commensurate with the expected life of the options in effect at the time of the grant. The expected dividend yield was zero, as the Company does not anticipate paying a dividend within the relevant time frame.
	The Company realized no income tax benefit from stock option exercises in each of the periods presented due to recurring losses and valuation allowances.
	Stock option activity under the Plan is as follows:
		Shares subject to
		Options Outstanding
		Number of			Weighted		Weighted	Aggregate
		Shares			Average		Average	Intrinsic
					Exercise		Remaining	Value
					Price		Contractual
							Term
							(in years)
	Balance at December 31, 2011	10,705			$	3.83	6.77	$	44,466
	Options granted	2,243			10.29
	Options exercised	(2,543	)		1.95
	Options forfeited and canceled	(769	)		6.26
	Balance at December 31, 2012	9,636			5.63		7.33	64,719
	Options granted	1,618			17.46
	Options exercised	(2,879	)		4.69
	Options forfeited and canceled	(1,152	)		8.65
	Balance at December 31, 2013	7,223			8.17		6.82	180,543
	Options granted	563			36.91
	Options exercised	(1,984	)		6.56
	Options forfeited and canceled	(514	)		16.25
	Balance at December 31, 2014	5,288			$	11.06	6.31	$	196,608
	Exercisable, December 31, 2014	3,599			$	6.54	5.43	$	150,011
	Vested and expected to vest, December 31, 2014	5,095			$	10.58	6.23	$	191,882
	The total intrinsic value of options exercised was $64,455, $45,454 and $18,950, for the years ended December 31, 2014, 2013 and 2012, respectively. Total cash proceeds from such option exercises were $13,007, $13,509 and $4,966 for the years ended December 31, 2014, 2013 and 2012, respectively.
	The grant date fair value of options that vested was $10,755, $8,206 and $5,736 during the years ended December 31, 2014, 2013 and 2012, respectively.
	As of December 31, 2014, the Company had unrecognized stock-based compensation expense of $14,777 related to stock options that will be recognized net of forfeitures over the average remaining vesting term of the options of 2.09 years.
	Restricted Stock Units
	A following table summarized the activity of RSUs, PSUs and stock-bonus awards:
		RSUs and PSUs
		Outstanding
		Number of			Granted
		Shares			Fair
					Value
					Per
					Unit
	Awarded and unvested at December 31, 2011	8			$	7.98
	Awards granted	—			—
	Awards vested	(6	)		7.98
	Awards forfeited	(1	)		7.98
	Awarded and unvested at December 31, 2012	1			7.98
	Awards granted	1,236			28.94
	Awards vested	(1	)		24.15
	Awards forfeited	(22	)		24.61
	Awarded and unvested at December 31, 2013	1,214			29.57
	Awards granted	2,362			39.77
	Awards vested	(396	)		30.79
Awards forfeited	(246	)		31.59
Awarded and unvested at December 31, 2014	2,934			$	37.45
As of December 31, 2014, there was $77,695 of unamortized stock-based compensation expense related to unvested RSUs and PSUs, which are expected to be recognized over a weighted average period of 3.22 years.
Performance Stock Units
During 2014, the Compensation Committee approved the grant of 121 PSUs to certain key employees. The PSU vesting conditions were based on individual performance targets. The Company recognized $267 of share-based compensation expense, net of estimated forfeitures, related to PSUs during 2014. Unamortized expense was $852 as of December 31, 2014, net of estimated forfeitures.
Stock Bonus Awards
The total accrued liability for the stock bonus awards was $1,771 and $852 as of December 31, 2014 and 2013, respectively. 22 shares of common stock earned under the stock bonus program were issued during the year ended December 31, 2014. Approximately 37 shares are expected to be issued during the first three months of the year ending December 31, 2015. Stock based compensation expense related to stock bonus program were $1,771 and $852 for the years ended December 31, 2014 and 2013.
Employee Stock Purchase Plan
On March 30, 2012, the Board of Directors and the Company’s stockholders approved the 2012 Employee Stock Purchase Plan (the "ESPP"), which became effective in April 2012. A total of 745 shares of the Company's common stock was initially reserved 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 with 2013 by the number of shares equal to 1% of the Company's shares outstanding on the immediately preceding December 31, but not to exceed 1,490 shares, unless the Board of Directors, in its discretion, determines to make a smaller increase. As of December 31, 2014, there were 926 shares of the Company's common stock available for future issuance under the ESPP.
The fair value of the option component of the ESPP shares was estimated at the grant date using the Black-Scholes option pricing model with the following weighted average assumptions:
	Year ended December 31,		Year ended December 31,
	2014		2013		2012*
Expected life (in years)	0.5		0.50 - 0.54		0.50 - 0.53
Volatility	45% - 52%		38% - 40%		46% - 51%
Risk-free interest rate	0.05% - 0.07%		0.08%		0.13% - 0.15%
Dividend yield	—%		—%		—%
* Employee participation in the ESPP did not begin until the second quarter of 2012.
The Company issued 194 shares and 217 shares under the ESPP in 2014 and 2013, respectively, at a weighted average exercise price per share of $23.94 and $13.07, respectively. As of December 31, 2014, the Company expects to recognize $803 of the total unamortized compensation cost related to employee purchases under the ESPP over a weighted average period of 0.37 years.
Restricted Stock
The Company granted 54 shares of restricted stock in the fourth quarter of 2014 to certain key employees with the total fair value of $2,357 and two-year cliff vesting in 2016. As of December 31, 2014, there was $2,161 of unamortized stock-based compensation expense related to the unvested shares of restricted stock. The shares of restricted stock are subject to forfeiture if employment terminates prior to the lapse of the restrictions, and are expensed over the vesting period. They are considered issued and outstanding shares of the Company at the grant date and have the same rights as other shares of common stock.

Net_Loss_per_Share

Net Loss per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share
	Basic net loss per share of common stock is calculated by dividing the net loss by the weighted‑average number of shares of common stock outstanding for the period. The weighted‑average number of shares of common stock used to calculate our basic net loss per share of common stock excludes those shares subject to repurchase related to stock options that were exercised prior to vesting and restricted shares issued to certain employees as these shares are not deemed to be issued for accounting purposes until they vest. Diluted net loss per share of common stock is computed by dividing the net loss using the weighted‑average number of shares of common stock, excluding common stock subject to repurchase, and, if dilutive, potential shares of common stock outstanding during the period. Basic and diluted net loss per common share was the same for all periods presented as the impact of all potentially dilutive securities outstanding was anti-dilutive.
	The following table presents the calculation of basic and diluted net loss per share:
		Years Ended December 31,
		2014				2013			2012
	Numerator:
	Net loss	$	(64,239	)		$	(27,531	)	$	(20,360	)
	Denominator:
	Weighted average number of common shares used in computing basic and diluted net loss per share	37,381				34,874			24,056
	Net loss per common share
	Basic and diluted net loss per share	$	(1.72	)		$	(0.79	)	$	(0.85	)
	The following table presents the potentially dilutive common shares outstanding that were excluded from the computation of diluted net loss per share of common stock for the periods presented because including them would have been anti-dilutive:
		December 31,
		2014			2013			2012
	Stock options to purchase common stock	5,288			7,223			9,636
	Restricted stock units	2,934			1,214			1
	Employee stock purchase plan	90			89			133
	Common stock subject to repurchase	54			1			4
	Bonus shares	37			22			—
	Common stock warrants	—			2			2
	Convertible senior notes	5,158			5,158			—
	Total	13,561			13,709			9,776

Segment_Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting
	Operating segments are reported in a manner consistent with the internal reporting supported and defined by the components of an enterprise about which separate financial information is available, provided and is evaluated regularly by the chief operating decision maker, or decision making group, in deciding how to allocate resources and in assessing performance. The Company's chief operating decision maker is its Chief Executive Officer. The Company's Chief Executive Officer reviews financial information presented on a consolidated basis and as a result, the Company concluded that it has only one operating and reportable segment.
	The following set forth total revenue by solutions offered by the Company and geographic area. Revenue by geographic area is based upon the billing address of the customer:
		Year Ended December 31,
		2014		2013		2012
	Total revenue by solution:
	Privacy, Protection and Security	$	151,291	$	101,083	$	78,979
	Archiving and Governance	44,316		36,848		27,316
	Total revenue	$	195,607	$	137,931	$	106,295
		Year Ended December 31,
		2014		2013		2012
	Total revenue by geographic area:
	United States	$	157,593	$	113,819	$	86,661
	Rest of world	38,014		24,112		19,634
	Total revenue	$	195,607	$	137,931	$	106,295
	The following sets forth long-lived tangible assets by geographic area:
		December 31,
		2014		2013
	Long-lived assets:
	United States	$	15,974	$	9,425
	Rest of world	2,744		1,796
	Total long-lived assets	$	18,718	$	11,221

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	The domestic and foreign components of loss before benefit from (provision for) income taxes were as follows for the years ended December 31, 2014, 2013 and 2012:
		Year Ended December 31,
		2014			2013			2012
	Domestic	$	(69,555	)	$	(34,284	)	$	(23,506	)
	Foreign	5,003			3,945			3,667
	Loss before benefit from (provision for) income taxes	$	(64,552	)	$	(30,339	)	$	(19,839	)
	The benefit from (provision for) income taxes is comprised of:
		Year Ended
		December 31,
		2014			2013			2012
	Current tax expense:
	Federal	$	—		$	—		$	—
	State	121			70			30
	Foreign	530			641			491
	Total current	651			711			521
	Deferred tax expense:
	Federal	(792		)	—			—
	State	—			—			—
	Foreign	(172		)	(3,519		)	—
	Total deferred	(964		)	(3,519		)	—
	(Benefit from) provision for income taxes	$	(313	)	$	(2,808	)	$	521
	The reconciliation of income tax expense at the statutory federal income tax rate of 34% to the income tax provision included in the consolidated statements of operations for the years ended December 31, 2014, 2013 and 2012 is as follows:
		Year Ended December 31,
		2014			2013			2012
	Tax at federal statutory rate	$	(21,948	)	$	(10,315	)	$	(6,745	)
	Foreign income tax rate differential	(600		)	(232		)	(262		)
	State, net of federal benefit	(1,692		)	(1,130		)	(822		)
	Stock compensation charges	1,304			636			1,256
	SubPart F and other permanent items	2,579			1,583			1,204
	Provision to return and other	3,621			937			1,074
	Research and development credits	(2,052		)	(2,112		)	(1,061		)
	Uncertain tax positions	391			617			301
	Valuation allowance	18,084			7,208			5,576
	(Benefit from) provision for income taxes	$	(313	)	$	(2,808	)	$	521
	Deferred tax assets and liabilities reflect the net tax effects of net operating loss and tax credit carryovers and the temporary differences between the carrying amount of assets and liabilities for financial reporting and the amounts used for income tax purposes. Significant components of the Company's deferred tax assets were as follows for the years ended December 31, 2014 and 2013:
		Year Ended
		December 31,
		2014			2013
	Deferred tax assets:
	Net operating loss carryforwards	$	75,376		$	60,280
	Tax credit carryforwards	9,566			8,228
	Research expenditures	2,494			3,314
	Deferred revenue	11,078			13,292
	Stock compensation	7,228			3,696
	Fixed assets	1,516			1,262
	Accruals and other	8,505			7,250
	Gross deferred tax assets	115,763			97,322
	Valuation allowance	(90,929		)	(71,052		)
	Total deferred tax assets	24,834			26,270
	Deferred tax liabilities:
	Intangible assets and other	(9,613		)	(7,769		)
	Interest expense on the Notes	(12,911		)	(16,090		)
	Total deferred tax liabilities	(22,524		)	(23,859		)
	Total net deferred tax assets	$	2,310		$	2,411
	Current deferred income tax assets (included in other current assets)	$	3,903		$	4,166
	Non-current deferred income tax liabilities (included in long-term liabilities)	$	1,593		$	1,755
	The Company records net deferred tax assets to the extent that Company believes these assets will more likely than not be realized. In making such determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax planning strategies and recent financial operations.
	Realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. The valuation allowance increased by approximately $19,877, $2,400 and $3,700 during the years ended December 31, 2014, 2013 and 2012, respectively. The total valuation allowance increase of $19,877 for the year ended December 31, 2014 included a reduction of $792 resulting from the acquisition of Nexgate, and an increase of $2,023 related to the Company's acquisition of NetCitadel.
	As of December 31, 2014 and 2013, the Company had net operating loss carry-forwards for federal income tax purposes of $284,974 and $187,700, respectively. The amount of federal net-operating loss carry-forwards at December 31, 2014 and 2013 for which a benefit will be recorded in APIC when realized is approximately $84,125 and $34,500, respectively. The federal net operating losses will begin to expire in 2018. As of December 31, 2014 and 2013, the Company had federal research credit carry-forwards of $5,071 and $4,200 respectively. The federal research and development credits will begin to expire in 2022.
	As of December 31, 2014 and 2013, the Company had net operating loss carry-forwards for state income tax purposes of approximately $183,913 and $146,400, respectively. The amount of state net-operating loss carry-forwards at December 31, 2014 and 2013 for which a benefit will be recorded in APIC when realized is approximately $44,407 and $11,700, respectively. The state net operating losses will expire between 2015 and 2034. As of December 31, 2014 and 2013, the Company had research and development credit carry-forwards for state income tax purpose of $7,080 and $5,900, respectively. The state research and development credits have no expiration period.
	As of December 31, 2013, the Company had net operating losses carry-forwards in its non-U.S. locations of approximately $3,900, there were no operating losses carry-forwards as of December 31, 2014. In addition, as of December 31, 2014 and 2013, the Company had research and development credit carry-forwards in its non-U.S. locations of approximately $2,878 and $2,700, respectively. The non-U.S. research and development credits will begin to expire in 2028.
	Utilization of the federal and state net operating losses may be subject to substantial annual limitation due to the ownership change limitations provided by the Internal Revenue Code and similar state provisions. Analyses have been conducted to determine whether an ownership change had occurred since inception. The analyses have indicated that although an ownership change occurred in a prior year, the net operating losses and research and development credits would not expire before utilization as a result of the ownership change. In the event the Company has subsequent changes in ownership, net operating losses and research and development credit carryovers could be limited and may expire unutilized as a result of the subsequent ownership change.
	The Company recognizes interest and penalties related to uncertain tax positions within the income tax expense line in the consolidated statements of operations. Accrued interest and penalties are included within the related tax liability line in the consolidated balance sheets. During the year ended December 31, 2014, the Company accrued interest and penalties of $9 as a component of income tax expense related to tax contingencies and has $242 of interest and penalties recorded as a long-term income tax liability as of December 31, 2014. During the year ended year ended December 31, 2013, the Company accrued interest and penalties of $8 as a component of income tax expense related to tax contingencies and had $233 of interest and penalties recorded as a long-term income tax liability.
As of December 31, 2014, the Company had recorded unrecognized tax benefits of $1,432 that if recognized, would benefit the Company's effective tax rate. As of December 31, 2013, the Company had recorded unrecognized tax benefits of $1,541 that if recognized, would benefit the Company's effective tax rate.
The Company does not anticipate that the amount of unrecognized tax benefits relating to tax positions existing at December 31, 2014 will significantly increase or decrease within the next twelve months.
Because of net operating loss and credit carry-forwards, all of the Company's tax years dating to inception in 2002 remain open to tax examination in all major tax jurisdictions. The Company is not currently under audit in any material jurisdictions.
The aggregate changes in the balance of gross unrecognized tax benefits were as follows:
Ending balance as of December 31, 2011	$	2,526
Increase in balances related to tax positions taken during the current period	357
Decrease in balances related to tax positions taken during the prior period	(135		)
Decrease in balances related to statute expirations during the current period	(8		)
Ending balance as of December 31, 2012	2,740
Increase in balances related to tax positions taken during the current period	618
Increase in balances related to tax positions taken during the prior period	517
Decrease in balances related to tax positions taken during the prior period	(40		)
Decrease in balances related to statute expirations during the current period	(12		)
Ending balance as of December 31, 2013	3,823
Increase in balances related to tax positions taken during the current period	524
Increase in balances related to tax positions taken during the prior period	—
Decrease in balances related to tax positions taken during the prior period	(87		)
Decrease in balances related to statute expirations during the current period	(31		)
Ending balance as of December 31, 2014	$	4,229
As of December 31, 2014, $200 of foreign withholding taxes associated with the repatriation of earning of foreign subsidiaries had been provided on $4,000 of undistributed earnings for certain foreign subsidiaries. The Company intends to reinvest the remainder of its undistributed earnings indefinitely outside the United States. As of December 31, 2014, the Company estimated that no material additional U.S. income taxes would have to be provided if all of the undistributed earnings of the foreign subsidiaries were repatriated back to the United States as substantially all earnings from its foreign subsidiaries are previously taxed income. As of December 31, 2014, the Company estimated that approximately $550 of additional foreign withholding tax would have to be provided if all of the undistributed earnings of the Company's foreign subsidiaries were repatriated back to the United States.

The_Company_and_Summary_of_Sig1

The Company and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Reverse Stock Split	Reverse Stock Split
	On March 30, 2012, the Company's Board of Directors approved a 1-for-2 reverse stock split of the Company's common stock. The reverse stock split became effective on April 2, 2012. Upon the effectiveness of the reverse stock split, (i) every two shares of outstanding common stock was decreased to one share of common stock, (ii) the number of shares of common stock into which each outstanding option to purchase common stock is exercisable was proportionally decreased on a 1-for-2 basis, (iii) the exercise price of each outstanding option to purchase common stock was proportionately increased on a 1-for-2 basis, and (iv) the conversion ratio for each share of preferred stock outstanding was proportionately reduced on a 1-for-2 basis. All of the share numbers, share prices, and exercise prices have been retrospectively adjusted to reflect the reverse stock split.
Principles of Consolidation	Principles of Consolidation
	The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.
	In 2014 and 2013, the Company completed a number of acquisitions which are more fully described in Note 2, "Acquisitions". The consolidated financial statements include the results of operations from these business combinations from their date of acquisition.
Use of Estimates	Use of Estimates
	The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of expenses during the reporting period. Actual results could differ materially from those estimates. Significant items subject to such estimates and assumptions include those related to revenue recognition, stock-based compensation expense, fair value of assets acquired and liabilities assumed in business combinations, impairment assessments of goodwill, intangible assets and other long-lived assets, loss contingencies, and the recognition and measurement of current and deferred income taxes.
Foreign Currency Remeasurement and Transactions	Foreign Currency Remeasurement and Transactions
	The functional currency for the Company's wholly-owned foreign subsidiaries is the U.S. dollar. Accordingly, the subsidiaries remeasure monetary assets and liabilities at period-end exchange rates, while nonmonetary items are remeasured at historical rates. Income and expense accounts are remeasured at the average exchange rates in effect during the year. Remeasurement adjustments are recognized in the consolidated statements of operations as transaction gains or losses within other income (expense), net, in the period of occurrence.
Cash and Cash Equivalents	Cash and Cash Equivalents
	The Company considers currency on hand, demand deposits, time deposits, money market funds and all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash and cash equivalents. Cash and cash equivalents are held in various financial institutions in the United States and internationally.
Investments	Investments
	The Company classifies all its investments as available-for-sale at the time of purchase since it is management's intent that these investments be available for current operations, and as such, includes these investments as short-term investments on its balance sheets. These investments consist of fixed-term deposits, commercial paper and investment-grade corporate debt securities with original maturities longer than three months. Short-term investments classified as available-for-sale are recorded at fair value with the related unrealized gains and losses included in accumulated other comprehensive income (loss), a component of stockholders' equity. Realized gains and losses are recorded in the consolidated statements of operations and comprehensive loss based on specific identification.
Inventories	Inventories
	Inventories are stated at lower of cost or market value, with costs computed on a first-in, first-out basis. Cost is determined using standard costs which approximate actual costs. The Company periodically reviews its inventories for excess and obsolete items and adjusts carrying costs to estimated net realizable values when they are determined to be less than cost.
	Inventories held at December 31, 2014 and 2013 consist primarily of finished goods.
Revenue Recognition	Revenue Recognition
	The Company derives its revenue primarily from two sources: (1) subscription revenue for rights related to the use of the security-as-a-service platform and (2) hardware, training and professional services revenue provided to customers related to their use of the platform. The Company records its revenues net of any value added or sales tax. Subscription revenue is derived from a subscription‑based enterprise licensing model with contract terms typically ranging from one to three years, and consists of (i) subscription fees from the licensing of the security-as-a-service platform, (ii) subscription fees for access to the on-demand elements of the platform and (iii) subscription fees for the right to access the Company’s customer support services.
	Revenue is recognized when all of the following criteria have been met:
	•	Persuasive evidence of an arrangement exists;
	•	Delivery has occurred or services have been rendered;
	•	Sales price is fixed or determinable; and
	•	Collectability is reasonably assured.
	The Company applies industry-specific software revenue recognition guidance to transactions involving the licensing of software, as well as related support, training, and other professional services. The Company has analyzed all of the elements included in its multiple element software arrangements and has determined that it does not have sufficient VSOE of fair value to allocate revenue to its subscription and software license agreements, support, training, and professional services. The Company defers all revenue under the software arrangement until the commencement of the subscription services and any associated professional services. Once the subscription services and the associated professional services have commenced, the entire fee from the arrangement is recognized ratably over the remaining period of the arrangement. If the professional services are essential to the functionality of the subscription, then the revenue recognition does not commence until such services are completed.
	The Company's revenue arrangements typically include subscription services to its security-as-a-service platform. These hosted on demand service arrangements do not provide customers with the right to take possession of the software supporting the hosted services. Certain arrangements also include the sale of hardware appliances. Revenue from hardware appliances containing software components and hardware components that function together to deliver the hardware appliance's essential functionality is excluded from the scope of the industry specific revenue recognition guidance. The Company recognizes revenue from its hosted on demand services in accordance with general revenue recognition accounting guidance. Only revenue derived from the licensing of the software is recognized in accordance with the industry specific revenue guidance.
	When a sales arrangement contains multiple elements, such as hardware appliances, subscription services, customer
	support services, and/or professional services, the Company allocates revenue to each unit of accounting or element based on a selling price hierarchy. An element constitutes a separate unit of accounting when the delivered item has standalone value and delivery of the undelivered element is probable and within the Company's control. When applying the relative selling price method, the Company determines the selling price for each deliverable using vendor-specific objective evidence (“VSOE”) of selling price. If VSOE does not exist, the Company uses third-party evidence (“TPE”) of selling price. If neither VSOE nor TPE of selling price exist for a deliverable, the Company uses its best estimate of selling price ("BESP") for that deliverable. Revenue allocated to each element is then recognized when the basic revenue recognition criteria are met for each element. The Company determines BESP for an individual element within a multiple element revenue arrangement using the same methods utilized to determine the selling price of an element sold on a standalone basis. The Company estimates the selling price for its subscription solutions by considering internal factors such as historical pricing practices and it estimates the selling price of hardware and other services using a cost plus model.
	Hardware appliance revenue is recognized upon shipment. Subscription and support revenue are recognized over the contract period commencing on the start date of the contract. Professional services and training, when sold with hardware appliances or subscription and support services, are accounted for separately when those services have standalone value. In determining whether professional services and training services can be accounted for separately from subscription and support services, the Company considers the following factors: availability of the services from other vendors, the nature of the services, and the dependence of the subscription services on the customer’s decision to buy the professional services. If professional services and training do not qualify for separate accounting, the Company recognizes the professional services and training ratably over the contract term of the subscription services.
	Delivery generally occurs when the hardware appliance is delivered to a common carrier freight on board shipping point by the Company or the hosted service has been activated and communicated to the customer accordingly. The Company’s fees are typically considered to be fixed or determinable at the inception of an arrangement and are negotiated at the outset of an arrangement, generally based on specific products and quantities to be delivered. In the event payment terms are provided that differ significantly from the Company's standard business practices, the fees are deemed to not be fixed or determinable and revenue is recognized as the fees become paid.
	The Company assesses collectability based on a number of factors, including credit worthiness of the customer and past transaction history of the customer. Through December 31, 2014, the Company has not experienced material credit losses.
Deferred Revenue	Deferred Revenue
	Deferred revenue primarily consists of billings or payments received in advance of revenue recognition from the sale of the Company’s subscription fees, training and professional services. Once the revenue recognition criteria are met, this revenue is recognized ratably over the term of the associated contract.
Deferred Product Costs	Deferred Product Costs
	Deferred product costs are the incremental costs that are directly associated with each noncancellable customer contract or hosting agreement and primarily consist of cost of appliances and royalty payments made to third parties, from whom the Company has obtained licenses to integrate certain software into its products. The costs are deferred and amortized over the noncancellable term of the related customer contract or hosting agreement, which typically range from 12 to 36 months.
Property and Equipment	Property and Equipment
	Property and equipment are stated at cost. Depreciation is computed using the straight-line method over the estimated useful life of the related asset. Amortization of leasehold improvements is computed using the straight-line method over the shorter of the lease term or the estimated useful life of the asset or improvement. Cost of maintenance and repairs that do not improve or extend the lives of the respective assets are expensed as incurred. When property and equipment are retired or otherwise disposed of, the cost and related accumulated depreciation are removed from the balance sheet and the resulting gain or loss is included in other (expense) income, net.
Impairment of Intangible Assets and Other Long-Lived Assets	Impairment of Intangible Assets and Other Long-Lived Assets
	The Company evaluates long-lived assets, such as property and equipment, including intangible assets other than goodwill, for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Recoverability of these assets is measured by comparison of the carrying amount of such assets (or asset group) to the future undiscounted cash flows the assets (or asset group) is expected to generate. If the assets are considered to be impaired, the amount of any impairment is measured as the difference between the carrying value and the fair value of the impaired assets. The Company also evaluates the estimated remaining useful lives of intangible assets and other long-lived assets to assess whether a revision to the remaining periods of amortization is required. No assets were determined to be impaired to date.
Advertising and Promotion Costs	Advertising and Promotion Costs
	Expenses related to advertising and promotion of solutions is charged to sales and marketing expense as incurred. The Company did not incur any significant advertising and promotion expenses during the years ended December 31, 2014, 2013 and 2012.
Goodwill and Intangible Assets	Goodwill and Intangible Assets
	Goodwill represents the excess of the purchase price of the acquired enterprise over the fair value of identifiable assets acquired and liabilities assumed. The Company performs an annual goodwill impairment test during the fourth quarter of the Company's fiscal year and more frequently if an event or circumstances indicates that impairment may have occurred. For the purposes of impairment testing, the Company has determined that it has one operating segment and one reporting unit. The Company performs a two-step impairment test of goodwill whereby the fair value of the reporting unit is compared to its carrying value. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that unit, goodwill is not considered impaired and further testing is not required. If the carrying value of the net assets assigned to the reporting unit exceeds the fair value of the reporting unit, then the Company must perform the second step of the impairment test in order to determine the implied fair value of the reporting unit’s goodwill. If the carrying value of a reporting unit’s goodwill exceeds its implied fair value, then impairment loss equal to the difference is recorded. The identification and measurement of goodwill impairment involves the estimation of the fair value of the Company. The estimate of fair value of the Company, based on the best information available as of the date of the assessment, is subjective and requires judgment, including management assumptions about expected future revenue forecasts and discount rates, changes in the overall economy, trends in the stock price and other factors. No impairment was identified by the Company as of December 31, 2014.
	Intangible assets consist of developed technology, customer relationships, non-compete arrangements, trademarks and patents, order backlog and in-process research and development asset. The values assigned to intangibles are based on estimates and judgments regarding expectations for success and life cycle of solutions and technologies acquired.
Warranty	Warranty
	The Company provides limited warranties on all sales and provides for the estimated cost of the warranties at the date of sale, to the extent not already provided by its own vendors.
Income Taxes	Income Taxes
	The Company accounts for income taxes in accordance with authoritative guidance, which requires use of the asset and liability method. Under this method, deferred income tax assets and liabilities are determined based on the difference between the consolidated financial statements carrying amounts and the tax basis of assets and liabilities and are measured using the enacted tax rates expected to apply to taxable income in the years in which the differences are expected to be reversed.
	The Company records net deferred tax assets to the extent the Company believes these assets will more likely than not be realized. In making such determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax planning strategies and recent financial operations.
	The Company has elected to use the "with and without" approach as described in ASC 740-20, "Intraperiod Tax Allocation" in determining the order in which tax attributes are utilized. As a result, the Company will only recognize a tax benefit from stock-based awards in additional paid-in capital if an incremental tax benefit is realized after all other tax attributes currently available to the Company have been utilized. In addition, the Company has elected to account for the impact of stock-based awards on other tax attributes, such as the research tax credit, within the consolidated statements of operations.
	The Company recognizes interest and penalties related to uncertain tax positions within the income tax expense line in the consolidated statements of operations. Accrued interest and penalties are included within the related tax liability line on the consolidated balance sheets.
Employee Benefit Plans	Employee Benefit Plans
	The Company sponsors a 401(k) defined contribution plan covering all employees. The Company may make discretionary contributions to the 401(k). To date, no contributions have been made by the Company.
Stock-Based Compensation	Stock-Based Compensation
	The Company issues stock-based compensation awards to employees and directors in the form of stock options, restricted stock units ("RSUs"), performance stock units ("PSUs") and employee stock purchase plan ("ESPP") awards (collectively, "awards").
	The Company measures and recognizes compensation expense for all stock-based awards based on the awards' fair value. Stock-based compensation for RSUs and PSUs is measured based on the value of the Company's common stock on the grant date. Stock-based compensation for employee stock options and ESPP awards are measured on the date of grant using a Black-Scholes option pricing model.
	Awards vest either on a graded schedule or in a lump sum. The Company determines the fair value of each award as a single award and recognizes the expense on a straight-line basis over the service period of the award, which is generally the vesting period. The exercise price of stock options granted is equal to the fair value of the Company's common stock on the date of grant. Stock options expire ten years from the date of grant.
	Stock-based compensation expense for stock options, RSUs, PSUs and the ESPP is based on awards ultimately expected to vest, and the expense is recorded net of estimated forfeitures.
Comprehensive Income (Loss)	Comprehensive Income (Loss)
	Comprehensive income (loss) includes all changes in equity that are not the result of transactions with stockholders. The Company’s comprehensive income (loss) consists of its net loss and changes in unrealized gains (losses) on its available-for-sale investments.
Loss Contingencies	Loss Contingencies
	The Company may be involved in various lawsuits, claims and proceedings that arise in the ordinary course of business. The Company records a provision for a liability when it believes that it is both probable that a liability has been incurred and the amount can be reasonably estimated. Significant judgment is required to determine both probability and the estimated amount. The Company reviews these provisions at least quarterly and adjusts these provisions to reflect the impact of negotiations, settlements, rulings, and updated information.
Recent Accounting Pronouncements	Recent Accounting Policies
	In June 2014, the FASB issued ASU 2014-12, Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period, a new accounting standard update that clarifies the accounting for share-based payments when the terms of an award allow for a performance target to be achieved after an employee completes the requisite period. The amendments require that a performance target that affects vesting and that could be achieved after the requisite period be treated as a performance condition. A company should apply existing guidance in Topic 718 as it relates to awards with performance conditions that affect vesting to account for such awards. Compensation cost should be recognized in the period in which it becomes probable that the performance target will be achieved and should represent the compensation cost attribute to the period(s) for which the requisite service has already been rendered. The new guidance will become effective for the Company on January 1, 2016 with early adoption is permitted. The adoption of this guidance is not expected to have material impact on the Company's consolidated financial statements.
	In May 2014, the FASB issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers: Topic 606 (ASU 2014-09), to supersede nearly all existing revenue recognition guidance under U.S. GAAP. The core principle of ASU 2014-09 is to recognize revenues when promised goods or services are transferred to customers in an amount that reflects the consideration that is expected to be received for those goods or services. ASU 2014-09 defines a five step process to achieve this core principle and, in doing so, it is possible more judgment and estimates may be required within the revenue recognition process than required under existing U.S. GAAP including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. ASU 2014-09 is effective for the Company starting January 1, 2017 using either of two methods: (i) retrospective to each prior reporting period presented with the option to elect certain practical expedients as defined within ASU 2014-09; or (ii) retrospective with the cumulative effect of initially applying ASU 2014-09 recognized at the date of initial application and providing certain additional disclosures as defined per ASU 2014-09. The Company is currently evaluating the impact of the adoption of ASU 2014-09 on its consolidated financial statements.

The_Company_and_Summary_of_Sig2

The Company and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Schedule of useful lives intangible assets	Intangible assets are amortized on a straight-line basis over their estimated lives, which approximate the pattern in which the economic benefits of the intangible assets are consumed, as follows (in years):
		Low	High
	Patents	4	5
	Developed technology	3	7
	Customer relationships	2	7
	Non-compete agreements	2	4
	Order backlog	2	2
	Tradenames and trademarks	1	5

Acquisitions_Tables

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2014
Business Acquisition [Line Items]
Schedule of pro forma information	Accordingly, these unaudited pro formas results are presented for informational purposes only and are not necessarily indicative of what the actual results of operations of the combined company would have been if the acquisitions had occurred at the beginning of the period presented, nor are they indicative of future results of operations:
		Twelve Months Ended December 31,
		2014				2013			2012
	Total revenue	$	196,701			$	166,577		$	150,934
	Net loss	(70,871		)		(46,090		)	(28,229		)
	Basic and diluted net loss per share	$	(1.90	)		$	(1.32	)	$	(1.17	)
Nexgate [Member]
Business Acquisition [Line Items]
Schedule of purchase price	The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
		Estimated			Estimated
		Fair Value in USD			Useful Life (in years)
	Current assets acquired	$	1,340		N/A
	Fixed assets acquired	15			N/A
	Liabilities assumed	(88		)	N/A
	Deferred revenue assumed	(600		)	N/A
	Customer relationships	3,000			7
	Order backlog	200			2
	Core/developed technology	3,200			4
	In-process research and development	900			N/A
	Deferred tax liability, net	(792		)	N/A
	Goodwill	25,628			Indefinite
		$	32,803
NetCitadel [Member]
Business Acquisition [Line Items]
Schedule of purchase price	The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
		Estimated			Estimated
		Fair Value in USD			Useful Life
	Tangible assets acquired	$	14		N/A
	Liabilities assumed	(1,267		)	N/A
	Customer relationships	100			5
	Core/developed technology	5,500			5
	Goodwill	18,384			Indefinite
		$	22,731
Sendmail [Member]
Business Acquisition [Line Items]
Schedule of purchase price	The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
		Fair Value in USD			Estimated
					Useful Life (in years)
	Tangible assets acquired	$	5,202		N/A
	Liabilities assumed	(5,162		)	N/A
	Deferred revenue assumed	(14,549		)	N/A
	Long-term debt assumed	(7,933		)	N/A
	Trade name	400			5
	Customer relationships	8,000			3
	Patents	300			5
	Core/developed technology	3,000			3
	Goodwill	24,322			Indefinite
		$	13,580
Armorize [Member]
Business Acquisition [Line Items]
Schedule of purchase price	The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
		Fair Value in USD			Estimated
					Useful Life (in years)
	Tangible assets acquired	$	2,754		N/A
	Liabilities assumed	(1,234		)	N/A
	Customer relationships	1,300			2
	Non-compete agreements	500			3
	Core/developed technology	3,850			5
	Goodwill	18,791			Indefinite
		$	25,961
Abaca Technologies [Member]
Business Acquisition [Line Items]
Schedule of purchase price	The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
		Fair Value in USD			Estimated
					Useful Life (in years)
	Tangible assets acquired	$	311		N/A
	Liabilities assumed	(962		)	N/A
	Customer relationships	40			3
	Core/developed technology	1,770			5
	Goodwill	264			Indefinite
		$	1,423
eDynamics [Member]
Business Acquisition [Line Items]
Schedule of purchase price	The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
		Fair Value in USD			Estimated
					Useful Life (in years)
	Customer relationships	$	243		3.5
	Non-compete agreements	75			2
	Core/developed technology	733			3.5
	Goodwill	107			Indefinite
		$	1,158
Mail Distiller [Member]
Business Acquisition [Line Items]
Schedule of purchase price	The following table summarizes the fair values of tangible assets acquired, liabilities assumed, intangible assets and goodwill:
		Fair Value in USD			Estimated
					Useful Life (in years)
	Tangible assets acquired	$	204		N/A
	Liabilities assumed	(1,052		)	N/A
	Trade name	7			1
	Customer relationships	1,291			2
	Non-compete agreements	123			2
	Core/developed technology	2,475			7
	Goodwill	1,452			Indefinite
		$	4,500

Balance_Sheet_Components_Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of allowance for doubtful accounts	Allowance for doubtful accounts activity and balances are presented below:
		Balance at				Additions				Write			Balance at
		Beginning of				to Costs and				Offs			End of
		Period				Expenses							Period
	Year ended December 31, 2012	$	233			$	54			$	(100	)	$	187
	Year ended December 31, 2013	$	187			$	91			$	(2	)	$	276
	Year ended December 31, 2014	$	276			$	158			$	(5	)	$	429
Schedule of property and equipment	Property and equipment at December 31, 2014 and 2013 consist of the following:
		Useful Life		December 31,
		(in years)		2014				2013
	Computer equipment	2 to 3		$	42,933			$	31,305
	Software	2		1,850				1,782
	Furniture	5		170				76
	Office equipment	2 to 5		582				397
	Leasehold improvements	5 years, or lease term, if shorter		4,341				1,298
	Other	2		59				59
	Construction in progress			643				339
				50,578				35,256
	Less: Accumulated depreciation			(31,860		)		(24,035		)
				$	18,718			$	11,221
Schedule of property and equipment acquired under capital leases	Property and equipment acquired under capital leases:
		December 31,
		2014				2013
	Computer equipment	$	346			$	346
	Less: Accumulated depreciation	(336		)		(317		)
		$	10			$	29
Schedule of accrued liabilities	Accrued liabilities at December 31, 2014 and 2013 consisted of the following:
		December 31,
		2014				2013
	Accrued compensation	$	15,206			$	8,886
	Customer deposits	1,484				2,098
	Accrued royalties	706				766
	Other	6,824				7,510
		$	24,220			$	19,260

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Components of intangible assets excluding goodwill	The goodwill activity and balances are presented below:
		December 31,
		2014			2013
	Opening balance	$	63,764		$	18,557
	Add: Goodwill from acquisitions	44,015			45,207
	Less: Other adjustments to Goodwill	(275		)	—
	Closing balance	$	107,504		$	63,764
Intangible assets excluding goodwill	Intangible assets excluding goodwill consisted of the following:
		31-Dec-14								31-Dec-13
		Gross			Accumulated			Net		Gross		Accumulated			Net
		Carrying			Amortization			Carrying		Carrying		Amortization			Carrying
		Amount						Amount		Amount					Amount
	Developed technology	$	38,168		$	(21,538	)	$	16,630	$	29,468	$	(17,383	)	$	12,085
	Customer relationships	16,382			(7,893		)	8,489		13,282		(3,726		)	9,556
	Non-compete agreements	804			(462		)	342		804		(170		)	634
	Trademark and patents	806			(264		)	542		806		(105		)	701
	Order backlog	200			(17		)	183		—		—			—
	In-process research and development	900			—			900		—		—			—
		$	57,260		$	(30,174	)	$	27,086	$	44,360	$	(21,384	)	$	22,976
Future estimated amortization costs of intangible assets	Future estimated amortization costs of intangible assets as of December 31, 2014 are presented below:
	Year Ended December 31,
	2015	$	9,717
	2016	7,424
	2017	4,195
	2018	3,616
	2019	1,252
	Thereafter	882
		$	27,086

Fair_Value_Measurements_and_In1

Fair Value Measurements and Investments (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair value, by balance sheet grouping	The following tables summarize, for each category of assets or liabilities carried at fair value, the respective fair value as of December 31, 2014 and 2013 and the classification by level of input within the fair value hierarchy:
		Balance as of				Quoted Prices		Significant			Unobservable
		December 31,				in Active		Other			Inputs
		2014				Markets for		Observable			(Level 3)
						Identical		Inputs
						Assets		(Level 2)
						(Level 1)
	Assets
	Cash equivalents:
	Money market funds	$	139,644			$	139,644	$	—		$	—
	Short-term investments:
	Corporate debt securities	31,651				—		31,651			—
	Commercial papers	2,998				—		2,998			—
	Total financial assets	$	174,293			$	139,644	$	34,649		$	—
		Balance as of				Quoted Prices		Significant			Unobservable
		December 31,				in Active		Other			Inputs
		2013				Markets for		Observable			(Level 3)
						Identical		Inputs
						Assets		(Level 2)
						(Level 1)
	Assets
	Cash equivalents:
	Money market funds	$	215,094			$	215,094	$	—		$	—
	Short-term investments:
	Corporate debt securities	6,015				—		6,015			—
	Certificates of deposit	2,000				—		2,000			—
	Total financial assets	$	223,109			$	215,094	$	8,015		$	—
	Liabilities
	Acquisition-related contingent earn-out liability	$	495			$	—	$	—		$	495
Fair value, liabilities measured on recurring basis, unobservable input reconciliation	The following table represents a reconciliation of the Acquisition-related contingent earn-out liability measured at fair value on a recurring basis, using significant unobservable inputs (Level 3) for the year ended December 31, 2014:
			Fair Value Measurements Using Significant Unobservable Inputs
			(Level 3)
	Balance at December 31, 2013		$	495
	Payments during the period		(500		)
	Adjustments to fair value during the period recorded in General and Administrative expenses		5
	Balance at December 31, 2014		$	—
Fair value of cash and cash equivalents, and investments	The cost and fair value of the Company’s cash and available-for-sale investments as of December 31, 2014 and 2013 were as follows:
		December 31, 2014
		Amortized Cost				Unrealized		Unrealized			Fair
						Gains		Losses			Value
	Cash and cash equivalents:
	Cash	$	40,693			$	—	$	—		$	40,693
	Money market funds	139,644				—		—			139,644
	Total	$	180,337			$	—	$	—		$	180,337
	Short-term investments:
	Corporate debt securities	$	31,678			$	—	$	(27	)	$	31,651
	Commercial paper	2,998				—		—			2,998
	Total	$	34,676			$	—	$	(27	)	$	34,649
		December 31, 2013
		Amortized Cost				Unrealized		Unrealized			Fair
						Gains		Losses			Value
	Cash and cash equivalents:
	Cash	$	28,692			$	—	$	—		$	28,692
	Money market funds	215,094				—		—			215,094
	Total	$	243,786			$	—	$	—		$	243,786
	Short-term investments:
	Corporate debt securities	$	6,015			$	—	$	—		$	6,015
	Certificate of deposit	2,000				—		—			2,000
	Total	$	8,015			$	—	$	—		$	8,015

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Future annual minimum lease payments under noncancellable operating and capital leases	At December 31, 2014, future annual minimum lease payments under noncancellable operating and capital leases were as follows:
		Capital			Operating
		Leases			Leases
	2015	$	11		$	7,961
	2016	—			6,949
	2017	—			3,762
	2018	—			3,628
	2019	—			3,515
	Thereafter	—			125
	Total minimum lease payments	11			$	25,940
	Less: Amount representing interest	—
	Present value of capital lease obligations	11
	Less: Current portion	(11		)
	Long-term portion of capital lease obligations	$	—

Convertible_Senior_Notes_Table

Convertible Senior Notes (Tables)	12 Months Ended
	Dec. 31, 2014
Senior Notes [Abstract]
Schedule of liability and equity components of convertible debt	At December 31, 2014, the net carrying amount of the liability component of the Notes consists of:
	Liability component:
	Principal	$	201,250
	Less: debt discount, net of amortization	(39,620		)
	Net carrying amount	$	161,630
	Equity component (1)	$	43,293
	(1) Recorded in the consolidated balance sheets as additional paid-in capital, net of the $1,285 issuance costs in equity
Schedule of convertible senior notes interest and accretion	For the years ended December 31, 2014 and 2013, the Company incurred the interest expense related to the Notes:
		2014			2013
	1.25% coupon	$	2,511		$	138
	Amortization of debt discount	8,702			486
	Amortization of debt issuance costs	51			3
	Total	$	11,264		$	627

Common_Stock_Tables

Common Stock (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Number of shares of common stock reserved for future issuance	Number of shares of common stock reserved for future issuance was as follows:
		December 31,
		2014	2013
	Shares available for future grant under the stock plans	4,330	4,584
	Options outstanding under stock plans	5,288	7,223
	Shares available for future issuance under ESPP	926	759
	Common stock issuable upon exercise of warrant and settlement of outstanding restricted stock units	2,934	1,216
	Common stock issuable upon conversion of the convertible senior notes	5,158	5,158
	Total shares reserved	18,636	18,940

Stock_Option_Plans_Tables

Stock Option Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Valuation assumptions	The weighted average fair value of stock options granted to employees during the years ended December 31, 2014, 2013 and 2012, was $20.25, $9.50 and $5.65, respectively. The fair values were estimated on the grant dates using the Black-Scholes option-pricing model with the following weighted-average assumptions:
		Year Ended December 31,
		2014		2013		2012
	Expected life (in years)	5.31-6.08		5.31 - 6.08		5.50 - 6.08
	Volatility	54% - 58%		57% - 61%		59% - 60%
	Risk-free interest rate	1.79% - 1.93%		0.9% - 1.8%		0.9% - 1.2%
	Dividend yield	—%		—%		—%
Activity under stock option plan	Stock option activity under the Plan is as follows:
		Shares subject to
		Options Outstanding
		Number of			Weighted		Weighted	Aggregate
		Shares			Average		Average	Intrinsic
					Exercise		Remaining	Value
					Price		Contractual
							Term
							(in years)
	Balance at December 31, 2011	10,705			$	3.83	6.77	$	44,466
	Options granted	2,243			10.29
	Options exercised	(2,543	)		1.95
	Options forfeited and canceled	(769	)		6.26
	Balance at December 31, 2012	9,636			5.63		7.33	64,719
	Options granted	1,618			17.46
	Options exercised	(2,879	)		4.69
	Options forfeited and canceled	(1,152	)		8.65
	Balance at December 31, 2013	7,223			8.17		6.82	180,543
	Options granted	563			36.91
	Options exercised	(1,984	)		6.56
	Options forfeited and canceled	(514	)		16.25
	Balance at December 31, 2014	5,288			$	11.06	6.31	$	196,608
	Exercisable, December 31, 2014	3,599			$	6.54	5.43	$	150,011
	Vested and expected to vest, December 31, 2014	5,095			$	10.58	6.23	$	191,882
Summary of RSUs awarded and unvested under stock option plan	A following table summarized the activity of RSUs, PSUs and stock-bonus awards:
		RSUs and PSUs
		Outstanding
		Number of			Granted
		Shares			Fair
					Value
					Per
					Unit
	Awarded and unvested at December 31, 2011	8			$	7.98
	Awards granted	—			—
	Awards vested	(6	)		7.98
	Awards forfeited	(1	)		7.98
	Awarded and unvested at December 31, 2012	1			7.98
	Awards granted	1,236			28.94
	Awards vested	(1	)		24.15
	Awards forfeited	(22	)		24.61
	Awarded and unvested at December 31, 2013	1,214			29.57
	Awards granted	2,362			39.77
	Awards vested	(396	)		30.79
	Awards forfeited	(246	)		31.59
	Awarded and unvested at December 31, 2014	2,934			$	37.45
ESPP 2012 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Valuation assumptions	The fair value of the option component of the ESPP shares was estimated at the grant date using the Black-Scholes option pricing model with the following weighted average assumptions:
		Year ended December 31,		Year ended December 31,
		2014		2013		2012*
	Expected life (in years)	0.5		0.50 - 0.54		0.50 - 0.53
	Volatility	45% - 52%		38% - 40%		46% - 51%
	Risk-free interest rate	0.05% - 0.07%		0.08%		0.13% - 0.15%
	Dividend yield	—%		—%		—%
	* Employee participation in the ESPP did not begin until the second quarter of 2012.

Net_Loss_per_Share_Tables

Net Loss per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Schedule of earnings per share, basic and diluted	The following table presents the calculation of basic and diluted net loss per share:
		Years Ended December 31,
		2014				2013			2012
	Numerator:
	Net loss	$	(64,239	)		$	(27,531	)	$	(20,360	)
	Denominator:
	Weighted average number of common shares used in computing basic and diluted net loss per share	37,381				34,874			24,056
	Net loss per common share
	Basic and diluted net loss per share	$	(1.72	)		$	(0.79	)	$	(0.85	)
Schedule of antidilutive securities excluded from computation of earnings per share	The following table presents the potentially dilutive common shares outstanding that were excluded from the computation of diluted net loss per share of common stock for the periods presented because including them would have been anti-dilutive:
		December 31,
		2014			2013			2012
	Stock options to purchase common stock	5,288			7,223			9,636
	Restricted stock units	2,934			1,214			1
	Employee stock purchase plan	90			89			133
	Common stock subject to repurchase	54			1			4
	Bonus shares	37			22			—
	Common stock warrants	—			2			2
	Convertible senior notes	5,158			5,158			—
	Total	13,561			13,709			9,776

Segment_Reporting_Tables

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Revenue from external customers by products and services
		Year Ended December 31,
		2014		2013		2012
	Total revenue by solution:
	Privacy, Protection and Security	$	151,291	$	101,083	$	78,979
	Archiving and Governance	44,316		36,848		27,316
	Total revenue	$	195,607	$	137,931	$	106,295
Total revenue and long-lived assets by geographic area
		Year Ended December 31,
		2014		2013		2012
	Total revenue by geographic area:
	United States	$	157,593	$	113,819	$	86,661
	Rest of world	38,014		24,112		19,634
	Total revenue	$	195,607	$	137,931	$	106,295
	The following sets forth long-lived tangible assets by geographic area:
		December 31,
		2014		2013
	Long-lived assets:
	United States	$	15,974	$	9,425
	Rest of world	2,744		1,796
	Total long-lived assets	$	18,718	$	11,221

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of domestic and foreign components of loss before benefit from (provision for) income taxes	The domestic and foreign components of loss before benefit from (provision for) income taxes were as follows for the years ended December 31, 2014, 2013 and 2012:
		Year Ended December 31,
		2014			2013			2012
	Domestic	$	(69,555	)	$	(34,284	)	$	(23,506	)
	Foreign	5,003			3,945			3,667
	Loss before benefit from (provision for) income taxes	$	(64,552	)	$	(30,339	)	$	(19,839	)
Schedule of components of income tax expense	The benefit from (provision for) income taxes is comprised of:
		Year Ended
		December 31,
		2014			2013			2012
	Current tax expense:
	Federal	$	—		$	—		$	—
	State	121			70			30
	Foreign	530			641			491
	Total current	651			711			521
	Deferred tax expense:
	Federal	(792		)	—			—
	State	—			—			—
	Foreign	(172		)	(3,519		)	—
	Total deferred	(964		)	(3,519		)	—
	(Benefit from) provision for income taxes	$	(313	)	$	(2,808	)	$	521
Schedule of reconciliation of income tax expense	The reconciliation of income tax expense at the statutory federal income tax rate of 34% to the income tax provision included in the consolidated statements of operations for the years ended December 31, 2014, 2013 and 2012 is as follows:
		Year Ended December 31,
		2014			2013			2012
	Tax at federal statutory rate	$	(21,948	)	$	(10,315	)	$	(6,745	)
	Foreign income tax rate differential	(600		)	(232		)	(262		)
	State, net of federal benefit	(1,692		)	(1,130		)	(822		)
	Stock compensation charges	1,304			636			1,256
	SubPart F and other permanent items	2,579			1,583			1,204
	Provision to return and other	3,621			937			1,074
	Research and development credits	(2,052		)	(2,112		)	(1,061		)
	Uncertain tax positions	391			617			301
	Valuation allowance	18,084			7,208			5,576
	(Benefit from) provision for income taxes	$	(313	)	$	(2,808	)	$	521
Schedule of deferred tax assets and liabilities	Significant components of the Company's deferred tax assets were as follows for the years ended December 31, 2014 and 2013:
		Year Ended
		December 31,
		2014			2013
	Deferred tax assets:
	Net operating loss carryforwards	$	75,376		$	60,280
	Tax credit carryforwards	9,566			8,228
	Research expenditures	2,494			3,314
	Deferred revenue	11,078			13,292
	Stock compensation	7,228			3,696
	Fixed assets	1,516			1,262
	Accruals and other	8,505			7,250
	Gross deferred tax assets	115,763			97,322
	Valuation allowance	(90,929		)	(71,052		)
	Total deferred tax assets	24,834			26,270
	Deferred tax liabilities:
	Intangible assets and other	(9,613		)	(7,769		)
	Interest expense on the Notes	(12,911		)	(16,090		)
	Total deferred tax liabilities	(22,524		)	(23,859		)
	Total net deferred tax assets	$	2,310		$	2,411
	Current deferred income tax assets (included in other current assets)	$	3,903		$	4,166
	Non-current deferred income tax liabilities (included in long-term liabilities)	$	1,593		$	1,755
Schedule of unrecognized tax benefits	The aggregate changes in the balance of gross unrecognized tax benefits were as follows:
	Ending balance as of December 31, 2011	$	2,526
	Increase in balances related to tax positions taken during the current period	357
	Decrease in balances related to tax positions taken during the prior period	(135		)
	Decrease in balances related to statute expirations during the current period	(8		)
	Ending balance as of December 31, 2012	2,740
	Increase in balances related to tax positions taken during the current period	618
	Increase in balances related to tax positions taken during the prior period	517
	Decrease in balances related to tax positions taken during the prior period	(40		)
	Decrease in balances related to statute expirations during the current period	(12		)
	Ending balance as of December 31, 2013	3,823
	Increase in balances related to tax positions taken during the current period	524
	Increase in balances related to tax positions taken during the prior period	—
	Decrease in balances related to tax positions taken during the prior period	(87		)
	Decrease in balances related to statute expirations during the current period	(31		)
	Ending balance as of December 31, 2014	$	4,229

The_Company_and_Summary_of_Sig3

The Company and Summary of Significant Accounting Policies - Narrative (Details) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reverse stock split:
Reverse stock split	0.5
Foreign currency remeasurement and transactions:
Aggregate foreign currency transaction gains (losses)		($2,182)	($180)	($157)
Minimum [Member]
Deferred product costs:
Number of months deferred product costs are recognized		12 months
Maximum [Member]
Deferred product costs:
Number of months deferred product costs are recognized		36 months

The_Company_and_Summary_of_Sig4

The Company and Summary of Significant Accounting Policies - Goodwill and Intangible Assets (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
Intangible assets:
Goodwill, impairment loss	$0
Minimum [Member] | Patents [Member]
Intangible assets:
Estimated life of intangible assets	4 years
Minimum [Member] | Developed technology rights [Member]
Intangible assets:
Estimated life of intangible assets	3 years
Minimum [Member] | Customer relationships [Member]
Intangible assets:
Estimated life of intangible assets	2 years
Minimum [Member] | Noncompete agreements [Member]
Intangible assets:
Estimated life of intangible assets	2 years
Minimum [Member] | Order Backlog [Member]
Intangible assets:
Estimated life of intangible assets	2 years
Minimum [Member] | Trademarks and trade names [Member]
Intangible assets:
Estimated life of intangible assets	1 year
Maximum [Member] | Patents [Member]
Intangible assets:
Estimated life of intangible assets	5 years
Maximum [Member] | Developed technology rights [Member]
Intangible assets:
Estimated life of intangible assets	7 years
Maximum [Member] | Customer relationships [Member]
Intangible assets:
Estimated life of intangible assets	7 years
Maximum [Member] | Noncompete agreements [Member]
Intangible assets:
Estimated life of intangible assets	4 years
Maximum [Member] | Order Backlog [Member]
Intangible assets:
Estimated life of intangible assets	2 years
Maximum [Member] | Trademarks and trade names [Member]
Intangible assets:
Estimated life of intangible assets	5 years

Acquisitions_2014_Acquisitions

Acquisitions - 2014 Acquisitions (Details) (USD $)	12 Months Ended			0 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 31, 2014	13-May-14
Business Acquisition [Line Items]
Payments to acquire businesses, net of cash acquired	$53,680	$40,972	$0
Acquisition-related costs	576
Goodwill	107,504	63,764	18,557
Nexgate [Member]
Business Acquisition [Line Items]
Payments to acquire businesses, net of cash acquired				31,771
Cash acquired from acquisitions				1,032
Acquisition-related costs	231
Contingent consideration arrangements, range of outcomes, value, high				5,250
Current assets acquired				1,340
Fixed assets acquired				15
Liabilities assumed				-88
Deferred revenue assumed				-600
Deferred tax liability, net				-792
Goodwill				25,628
Recognized identifiable assets acquired and liabilities assumed, net				32,803
Nexgate [Member] | Customer relationships [Member]
Business Acquisition [Line Items]
Intangible assets				3,000
Acquired finite-lived intangible assets, weighted average useful life				7 years
Nexgate [Member] | Order Backlog [Member]
Business Acquisition [Line Items]
Intangible assets				200
Acquired finite-lived intangible assets, weighted average useful life				2 years
Nexgate [Member] | Core/developed technology [Member]
Business Acquisition [Line Items]
Intangible assets				3,200
Acquired finite-lived intangible assets, weighted average useful life				4 years
Nexgate [Member] | In Process Research and Development [Member]
Business Acquisition [Line Items]
Intangible assets				900
NetCitadel [Member]
Business Acquisition [Line Items]
Acquisition-related costs	345
Cash consideration for acquisition					22,731
Contingent consideration arrangements, range of outcomes, value, high					3,369
Fixed assets acquired					14
Liabilities assumed					-1,267
Goodwill					18,384
Recognized identifiable assets acquired and liabilities assumed, net					22,731
NetCitadel [Member] | Customer relationships [Member]
Business Acquisition [Line Items]
Intangible assets					100
Acquired finite-lived intangible assets, weighted average useful life					5 years
NetCitadel [Member] | Core/developed technology [Member]
Business Acquisition [Line Items]
Intangible assets					$5,500
Acquired finite-lived intangible assets, weighted average useful life					5 years

Acquisitions_2013_Acquisitions

Acquisitions - 2013 Acquisitions(Details) (USD $)	12 Months Ended			0 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 01, 2013	Sep. 05, 2013	Jul. 19, 2013	Jul. 10, 2013	Apr. 05, 2013
	business	business
Business Acquisition [Line Items]
Number of businesses acquired	2	5
Revenue	$195,607	$137,931	$106,295
Payments to acquire businesses, net of cash acquired	53,680	40,972	0
Liabilities arising from contingencies, amount recognized		495
Payment of contingent earn-out	487	99	0
Acquisition-related costs	576
Goodwill	107,504	63,764	18,557
Sendmail [Member]
Business Acquisition [Line Items]
Revenue		2,975
Payments to acquire businesses, net of cash acquired				12,463
Cash acquired from acquisitions				1,117
Contingent consideration arrangements, range of outcomes, value, high				3,422
Amount of indemnification obligation recovery	719
Acquisition-related costs		1,877
Tangible assets acquired				5,202
Liabilities assumed				-5,162
Deferred revenue assumed				-14,549
Long-term debt assumed				-7,933
Goodwill				24,322
Recognized identifiable assets acquired and liabilities assumed, net				13,580
Armorize [Member]
Business Acquisition [Line Items]
Revenue		781
Payments to acquire businesses, net of cash acquired					24,215
Cash acquired from acquisitions					1,746
Contingent consideration arrangements, range of outcomes, value, high					3,750
Acquisition-related costs		747
Tangible assets acquired					2,754
Liabilities assumed					-1,234
Goodwill					18,791
Recognized identifiable assets acquired and liabilities assumed, net					25,961
Abaca Technologies [Member]
Business Acquisition [Line Items]
Revenue		311
Payments to acquire businesses, net of cash acquired						23
Cash acquired from acquisitions						3
Contingent consideration arrangements, range of outcomes, value, high						1,520
Liabilities arising from contingencies, amount recognized						1,397
Acquisition-related costs		218
Tangible assets acquired						311
Liabilities assumed						-962
Goodwill						264
Recognized identifiable assets acquired and liabilities assumed, net						1,423
eDynamics [Member]
Business Acquisition [Line Items]
Cash consideration for acquisition							500
Acquisition-related costs		6
Goodwill							107
Recognized identifiable assets acquired and liabilities assumed, net							1,158
Mail Distiller [Member]
Business Acquisition [Line Items]
Revenue		216
Payments to acquire businesses, net of cash acquired								3,771
Cash acquired from acquisitions								60
Contingent consideration arrangements, range of outcomes, value, high		669
Acquisition-related costs		258
Tangible assets acquired								204
Liabilities assumed								-1,052
Goodwill								1,452
Recognized identifiable assets acquired and liabilities assumed, net								4,500
Trademarks and trade names [Member] | Sendmail [Member]
Business Acquisition [Line Items]
Finite lived intangible assets				400
Acquired finite-lived intangible assets, weighted average useful life				5 years
Trademarks and trade names [Member] | Mail Distiller [Member]
Business Acquisition [Line Items]
Finite lived intangible assets								7
Acquired finite-lived intangible assets, weighted average useful life								1 year
Customer relationships [Member] | Sendmail [Member]
Business Acquisition [Line Items]
Finite lived intangible assets				8,000
Acquired finite-lived intangible assets, weighted average useful life				3 years
Customer relationships [Member] | Armorize [Member]
Business Acquisition [Line Items]
Finite lived intangible assets					1,300
Acquired finite-lived intangible assets, weighted average useful life					2 years
Customer relationships [Member] | Abaca Technologies [Member]
Business Acquisition [Line Items]
Finite lived intangible assets						40
Acquired finite-lived intangible assets, weighted average useful life						3 years
Customer relationships [Member] | eDynamics [Member]
Business Acquisition [Line Items]
Finite lived intangible assets							243
Acquired finite-lived intangible assets, weighted average useful life							3 years 6 months
Customer relationships [Member] | Mail Distiller [Member]
Business Acquisition [Line Items]
Finite lived intangible assets								1,291
Acquired finite-lived intangible assets, weighted average useful life								2 years
Patents [Member] | Sendmail [Member]
Business Acquisition [Line Items]
Finite lived intangible assets				300
Acquired finite-lived intangible assets, weighted average useful life				5 years
Patents [Member] | Mail Distiller [Member]
Business Acquisition [Line Items]
Finite lived intangible assets								123
Acquired finite-lived intangible assets, weighted average useful life								2 years
Noncompete agreements [Member] | Armorize [Member]
Business Acquisition [Line Items]
Finite lived intangible assets					500
Acquired finite-lived intangible assets, weighted average useful life					3 years
Noncompete agreements [Member] | eDynamics [Member]
Business Acquisition [Line Items]
Finite lived intangible assets							75
Acquired finite-lived intangible assets, weighted average useful life							2 years
Core/developed technology [Member] | Sendmail [Member]
Business Acquisition [Line Items]
Finite lived intangible assets				3,000
Acquired finite-lived intangible assets, weighted average useful life				3 years
Core/developed technology [Member] | Armorize [Member]
Business Acquisition [Line Items]
Finite lived intangible assets					3,850
Acquired finite-lived intangible assets, weighted average useful life					5 years
Core/developed technology [Member] | Abaca Technologies [Member]
Business Acquisition [Line Items]
Finite lived intangible assets						1,770
Acquired finite-lived intangible assets, weighted average useful life						5 years
Core/developed technology [Member] | eDynamics [Member]
Business Acquisition [Line Items]
Finite lived intangible assets							733
Acquired finite-lived intangible assets, weighted average useful life							3 years 6 months
Core/developed technology [Member] | Mail Distiller [Member]
Business Acquisition [Line Items]
Finite lived intangible assets								2,475
Acquired finite-lived intangible assets, weighted average useful life								7 years
Earn-out consideration [Member] | eDynamics [Member]
Business Acquisition [Line Items]
Contingent consideration arrangements, range of outcomes, value, high							600
Liabilities arising from contingencies, amount recognized							586
Payment of contingent earn-out		100
Indemnification obligations [Member] | eDynamics [Member]
Business Acquisition [Line Items]
Contingent consideration arrangements, range of outcomes, value, high							100
Liabilities arising from contingencies, amount recognized							$72

Acquisitions_Pro_Forma_Financi

Acquisitions - Pro Forma Financial Information (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Combinations [Abstract]
Total revenue	$196,701	$166,577	$150,934
Net loss	-70,871	-46,090	-28,229
Basic net loss per share (in dollars per share)	($1.90)	($1.32)	($1.17)
Diluted net loss per share (in dollars per share)	($1.90)	($1.32)	($1.17)
Acquisition-related costs	$576

Concentration_of_Risks_Details

Concentration of Risks (Details) (Total revenue [Member], Major Customer [Member])	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	customer	customer	customer
Total revenue [Member] | Major Customer [Member]
Concentration Risk [Line Items]
Number of customers	1	1	1
Concentration risk percentage	12.00%	14.00%	14.00%

Balance_Sheet_Components_Allow

Balance Sheet Components - Allowance for Doubtful Accounts (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at Beginning of Period	$276	$187	$233
Additions to Costs and Expenses	158	91	54
Write Offs	-5	-2	-100
Balance at End of Period	$429	$276	$187

Balance_Sheet_Components_Prope

Balance Sheet Components - Property and Equipment (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property and Equipment
Property and equipment, gross	$50,578	$35,256
Less: Accumulated depreciation	-31,860	-24,035
Property and equipment, net	18,718	11,221
Computer equipment [Member]
Property and Equipment
Property and equipment, gross	42,933	31,305
Computer equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life	2 years
Computer equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life	3 years
Software [Member]
Property, Plant and Equipment [Line Items]
Useful life	2 years
Property and Equipment
Property and equipment, gross	1,850	1,782
Furniture [Member]
Property, Plant and Equipment [Line Items]
Useful life	5 years
Property and Equipment
Property and equipment, gross	170	76
Office equipment [Member]
Property and Equipment
Property and equipment, gross	582	397
Office equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life	2 years
Office equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life	5 years
Leasehold improvements [Member]
Property and Equipment
Property and equipment, gross	4,341	1,298
Leasehold improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life	5 years
Other [Member]
Property, Plant and Equipment [Line Items]
Useful life	2 years
Property and Equipment
Property and equipment, gross	59	59
Construction in progress [Member]
Property and Equipment
Property and equipment, gross	$643	$339

Balance_Sheet_Components_Prope1

Balance Sheet Components - Property and Equipment, Other Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property and equipment acquired under capital leases
Depreciation expense	$9,033	$5,923	$4,434
Capitalized software development costs				400
Amortization of capitalized software development costs		159	200
Computer equipment [Member]
Property and equipment acquired under capital leases
Capital leased assets, gross	346	346
Less: Accumulated depreciation	-336	-317
Capital leased assets, net	10	29
Capital leases [Member]
Property and equipment acquired under capital leases
Depreciation expense	$19	$48	$42

Balance_Sheet_Components_Accru

Balance Sheet Components - Accrued Liabilities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued compensation	$15,206	$8,886
Customer deposits	1,484	2,098
Accrued royalties	706	766
Other	6,824	7,510
Total accrued liabilities	$24,220	$19,260

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets - Goodwill (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Goodwill activity and balances
Opening balance	$63,764	$18,557
Add: Goodwill from acquisitions	44,015	45,207
Less: Other adjustments to Goodwill	-275	0
Closing balance	$107,504	$63,764

Goodwill_and_Intangible_Assets3

Goodwill and Intangible Assets - Intangible Assets (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Intangible assets excluding goodwill:
Gross Carrying Amount	$57,260	$44,360
Accumulated Amortization	-30,174	-21,384
Net Carrying Amount	27,086	22,976
Intangible amortization expense	8,790	4,044	3,276
Future estimated amortization costs of intangible assets:
2015	9,717
2016	7,424
2017	4,195
2018	3,616
2019	1,252
Thereafter	882
Net Carrying Amount	27,086	22,976
Developed technology rights [Member]
Intangible assets excluding goodwill:
Gross Carrying Amount	38,168	29,468
Accumulated Amortization	-21,538	-17,383
Net Carrying Amount	16,630	12,085
Future estimated amortization costs of intangible assets:
Net Carrying Amount	16,630	12,085
Customer relationships [Member]
Intangible assets excluding goodwill:
Gross Carrying Amount	16,382	13,282
Accumulated Amortization	-7,893	-3,726
Net Carrying Amount	8,489	9,556
Future estimated amortization costs of intangible assets:
Net Carrying Amount	8,489	9,556
Noncompete agreements [Member]
Intangible assets excluding goodwill:
Gross Carrying Amount	804	804
Accumulated Amortization	-462	-170
Net Carrying Amount	342	634
Future estimated amortization costs of intangible assets:
Net Carrying Amount	342	634
Trademark and patents [Member]
Intangible assets excluding goodwill:
Gross Carrying Amount	806	806
Accumulated Amortization	-264	-105
Net Carrying Amount	542	701
Future estimated amortization costs of intangible assets:
Net Carrying Amount	542	701
Order Backlog [Member]
Intangible assets excluding goodwill:
Gross Carrying Amount	200	0
Accumulated Amortization	-17	0
Net Carrying Amount	183	0
Future estimated amortization costs of intangible assets:
Net Carrying Amount	183	0
In Process Research and Development [Member]
Intangible assets excluding goodwill:
Gross Carrying Amount	900	0
Accumulated Amortization	0	0
Net Carrying Amount	900	0
Future estimated amortization costs of intangible assets:
Net Carrying Amount	$900	$0

Fair_Value_Measurements_and_In2

Fair Value Measurements and Investments - Fair Value Measurements (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair value measurements and investments:
Cash and cash equivalents, fair value disclosure	$180,337	$243,786
Short-term investments, fair value disclosure	34,649	8,015
Assets, fair value disclosure	174,293	223,109
Liabilities arising from contingencies, amount recognized		495
Money market funds [Member]
Fair value measurements and investments:
Cash and cash equivalents, fair value disclosure	139,644	215,094
Corporate debt securities [Member]
Fair value measurements and investments:
Short-term investments, fair value disclosure	31,651	6,015
Commercial paper [Member]
Fair value measurements and investments:
Short-term investments, fair value disclosure	2,998
Certificates of deposit [Member]
Fair value measurements and investments:
Short-term investments, fair value disclosure		2,000
Quoted prices in active markets for indentical assets (Level 1)
Fair value measurements and investments:
Assets, fair value disclosure	139,644	215,094
Quoted prices in active markets for indentical assets (Level 1) | Money market funds [Member]
Fair value measurements and investments:
Cash and cash equivalents, fair value disclosure	139,644	215,094
Significant other observable inputs (Level 2)
Fair value measurements and investments:
Assets, fair value disclosure	34,649	8,015
Convertible debt, fair value disclosures	277,725
Significant other observable inputs (Level 2) | Corporate debt securities [Member]
Fair value measurements and investments:
Short-term investments, fair value disclosure	31,651	6,015
Significant other observable inputs (Level 2) | Commercial paper [Member]
Fair value measurements and investments:
Short-term investments, fair value disclosure	2,998
Significant other observable inputs (Level 2) | Certificates of deposit [Member]
Fair value measurements and investments:
Short-term investments, fair value disclosure		2,000
Unobservable inputs (Level 3)
Fair value measurements and investments:
Liabilities arising from contingencies, amount recognized		495
Unobservable inputs (Level 3) | Earn-out consideration [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liability Value, Beginning Balance	495
Fair value, measurement with unobservable inputs reconciliation, recurring basis, liability, settlements	-500
Fair value, measurement with unobservable inputs reconciliation, recurring basis, liability, gain (loss) included in earnings	5
Liability Value, Ending Balance	$0

Fair_Value_Measurements_and_In3

Fair Value Measurements and Investments - Investments (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Cash and Cash Equivalents, and Investments [Line Items]
Cash and cash equivalents, at carrying value	$180,337	$243,786	$39,254	$9,767
Cash and cash equivalents, fair value disclosure	180,337	243,786
Short-term investments, amortized cost basis	34,676	8,015
Short-term investments, gross unrealized gains	0	0
Short-term investments, gross unrealized losses	-27	0
Short-term investments, fair value disclosure	34,649	8,015
Maximum investment maturity term	1 year	1 year
Cash [Member]
Schedule of Cash and Cash Equivalents, and Investments [Line Items]
Cash and cash equivalents, at carrying value	40,693	28,692
Cash and cash equivalents, fair value disclosure	40,693	28,692
Money market funds [Member]
Schedule of Cash and Cash Equivalents, and Investments [Line Items]
Cash and cash equivalents, at carrying value	139,644	215,094
Cash and cash equivalents, fair value disclosure	139,644	215,094
Corporate debt securities [Member]
Schedule of Cash and Cash Equivalents, and Investments [Line Items]
Short-term investments, amortized cost basis	31,678	6,015
Short-term investments, gross unrealized gains	0	0
Short-term investments, gross unrealized losses	-27	0
Short-term investments, fair value disclosure	31,651	6,015
Commercial paper [Member]
Schedule of Cash and Cash Equivalents, and Investments [Line Items]
Short-term investments, amortized cost basis	2,998
Short-term investments, gross unrealized gains	0
Short-term investments, gross unrealized losses	0
Short-term investments, fair value disclosure	2,998
Certificates of deposit [Member]
Schedule of Cash and Cash Equivalents, and Investments [Line Items]
Short-term investments, amortized cost basis		2,000
Short-term investments, gross unrealized gains		0
Short-term investments, gross unrealized losses		0
Short-term investments, fair value disclosure		$2,000

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	0 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Apr. 15, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 31, 2012
Commitments and Contingencies Disclosure [Abstract]
Operating leases rent expense		$3,283	$1,774	$1,520
Capital Leases
2015		11
2016		0
2017		0
2018		0
2019		0
Thereafter		0
Total minimum capital lease payments		11
Less: Amount representing interest		0
Present value of capital lease obligations		11
Less: Current portion		-11
Long-term portion of capital lease obligations		0
Operating Leases
2015		7,961
2016		6,949
2017		3,762
2018		3,628
2019		3,515
Thereafter		125
Total minimum operating lease payments		25,940
Commitments and contingencies:
Damages sought, value	$13,500
Capital leases
Commitments and contingencies:
Interest rate, stated percentage					4.50%

Convertible_Senior_Notes_Detai

Convertible Senior Notes (Details) (USD $)	12 Months Ended		0 Months Ended	3 Months Ended
Share data in Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 11, 2013	Mar. 31, 2014
				D
Liability component:
Net carrying amount	$161,630,000	$152,928,000
Interest Expense, Debt
Interest expense, 1.25% coupon	2,511,000	138,000
Amortization of debt discount	8,702,000	486,000
Amortization of debt issuance costs	51,000	3,000
Interest expense, total	11,264,000	627,000
1.25% Convertible Senior Notes [Member] | Senior Notes [Member]
Debt:
Face amount, optional			26,250,000
Debt issuance cost			5,803,000
Proceeds from convertible debt			195,446,000
Debt interest rate			1.25%
Threshold percentage of stock price trigger				130.00%
Threshold trading days				20
Threshold consecutive trading days	5 days			30 days
Number of consecutive business days following consecutive trading day period	5 days
Trading price as percentage of closing price of common stock	98.00%
Effective rate used to amortization debt discount			6.50%
Carrying amount of the equity component net			44,578,000
Liability component:
Principal	201,250,000		175,000,000
Less: debt discount, net of amortization	-39,620,000
Net carrying amount	161,630,000		156,672,000
Equity component	43,293,000
Issuance costs allocated to equity portion	$1,285,000
Common stock [Member] | 1.25% Convertible Senior Notes [Member] | Senior Notes [Member]
Debt:
Conversion ratio, initial			25.6271
Number of shares convertible, initial rate			5,158
Conversion price per share, initial			$39.02

Debt_Details

Debt (Details) (Loans payable [Member], USD $)	0 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Apr. 30, 2011	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt:
Long-term Debt	$6,000
Interest rate at period end		4.50%
Duration until repayment date after a loan amount is drawn	48 months
Interest expense		65	140	211
New equipment loan arrangement [Member]
Debt:
Borrowings outstanding and payable in 2015		$684
Prime Rate [Member]
Debt:
Basis spread on variable rate	0.50%

Common_Stock_Details

Common Stock (Details) (USD $)	3 Months Ended	1 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Apr. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stockholders' Equity:
Reverse stock split	0.5
Total shares authorized (in shares)			205,000,000
Preferred stock authorized (in shares)			5,000,000
Common stock authorized (in shares)			200,000,000	200,000,000
Par value of common stock (USD per share)			$0.00	$0.00
Number of shares of common stock reserved for future issuance
Total shares reserved			18,636,000	18,940,000
Employee stock option [Member]
Number of shares of common stock reserved for future issuance
Shares available for future grant under the stock plans			4,330,000	4,584,000
Options outstanding under stock plans				7,223,000
Restricted stock units (RSUs) [Member]
Number of shares of common stock reserved for future issuance
Common stock issuable upon exercise of warrant and settlement of outstanding restricted stock units			2,934,000	1,216,000
Convertible debt [Member]
Number of shares of common stock reserved for future issuance
Common stock issuable upon conversion of the convertible senior notes			5,158,000	5,158,000
Common stock [Member]
Stockholders' Equity:
Stock issued from conversion of convertible securities (in shares)		19,567,000
IPO [Member] | Common stock [Member]
Stockholders' Equity:
Stock issued during period (in shares)		5,859,000
Stock issued sold by selling shareholders (in shares)		1,370,000
Public offering price (USD per share)		13
Proceeds from issuance, before deducting underwriter discounts and offering expenses		76,200
Proceeds from issuance of common stock		68,300
Underwriters overallotment [Member] | Common stock from the exercise of the overallotment option of shares granted to the underwriters [Member]
Stockholders' Equity:
Stock issued during period (in shares)		729,000
Stock issued sold by selling shareholders (in shares)		171,000
2012 Equity Incentive Plan [Member] | Employee stock option [Member]
Number of shares of common stock reserved for future issuance
Options outstanding under stock plans			5,288,000	7,223,000	9,636,000	10,705,000
ESPP 2012 Plan [Member]
Number of shares of common stock reserved for future issuance
Shares available for future issuance under ESPP			926,000	759,000

Stock_Option_Plans_StockBased_

Stock Option Plans - Stock-Based Compensation Plans (Details)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
	plan
Stock-based compensation:
Equity incentive plans held by the Company (number of plans)	2
Employee stock option [Member]
Stock-based compensation:
Options available for future grant under the stock plans	4,330	4,584
2012 Equity Incentive Plan [Member]
Stock-based compensation:
Shares authorized for issuance (in shares)	20,316
Annual percentage increase in number of shares authorized	5.00%
Maximum number of additional shares to be authorized	3,724
2012 Equity Incentive Plan [Member] | Employee stock option [Member] | Maximum [Member]
Stock-based compensation:
Term until award expiration	10 years
Award vesting period	4 years
2012 Equity Incentive Plan [Member] | Employee stock option [Member] | Minimum [Member]
Stock-based compensation:
Award vesting period	3 years
2012 Equity Incentive Plan [Member] | Restricted stock [Member]
Stock-based compensation:
Award vesting period	4 years

Stock_Option_Plans_Stock_Optio

Stock Option Plans - Stock Option Activity (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock option activity under the Plan:
Options granted (in shares)		1,618
Options exercised (in shares)		-2,879
Shares subject to options outstanding, weighted average exercise price:
Options granted (USD per share)		$17.46
Options exercised (USD per share)		$4.69
Employee stock option [Member]
Stock-based compensation:
Weighted-average fair value of stock options granted	$20.25	$9.50	$5.65
Fair value assumptions:
Dividend yield	0.00%	0.00%	0.00%
Stock option activity under the Plan:
Outstanding, beginning of period (in shares)	7,223
Outstanding, end of period (in shares)		7,223
Shares subject to options outstanding, weighted average exercise price:
Total intrinsic value of options exercised	$64,455	$45,454	$18,950
Total proceeds from option exercises	13,007	13,509	4,966
Fair value of option grants that vested	10,755	8,206	5,736
2012 Equity Incentive Plan [Member] | Employee stock option [Member]
Stock option activity under the Plan:
Outstanding, beginning of period (in shares)	7,223	9,636	10,705
Options granted (in shares)	563		2,243
Options exercised (in shares)	-1,984		-2,543
Options forfeited and canceled (in shares)	-514	-1,152	-769
Outstanding, end of period (in shares)	5,288	7,223	9,636	10,705
Exercisable (in shares)	3,599
Vested and expected to vest (in shares)	5,095
Shares subject to options outstanding, weighted average exercise price:
Balance at beginning of period (USD per share)	$8.17	$5.63	$3.83
Options granted (USD per share)	$36.91		$10.29
Options exercised (USD per share)	$6.56		$1.95
Options forfeited and canceled (USD per share)	$16.25	$8.65	$6.26
Balance at end of period (USD per share)	$11.06	$8.17	$5.63	$3.83
Exercisable (in USD per share)	$6.54
Vested and expected to vest (in USD per share)	$10.58
Weighted average remaining contractual term	6 years 3 months 22 days	6 years 9 months 26 days	7 years 3 months 29 days	6 years 9 months 7 days
Weighted average remaining contractual term, Exercisable	5 years 5 months 5 days
Weighted average remaining contractual term, Vested and expected to vest	6 years 2 months 23 days
Aggregate intrinsic value	196,608	180,543	64,719	44,466
Aggregate intrinsic value, exercisable	150,011
Aggregate intrinsic value, vested and expected to vest	191,882
Unrecognized stock-based compensation expense	$14,777
Average remaining vesting term	2 years 1 month 2 days
Maximum [Member] | Employee stock option [Member]
Fair value assumptions:
Expected life (in years)	6 years 29 days	6 years 29 days	6 years 29 days
Volatility	58.00%	61.00%	60.00%
Risk-free interest rate	1.93%	1.80%	1.20%
Minimum [Member] | Employee stock option [Member]
Fair value assumptions:
Expected life (in years)	5 years 3 months 23 days	5 years 3 months 23 days	5 years 6 months
Volatility	54.00%	57.00%	59.00%
Risk-free interest rate	1.79%	0.90%	0.90%

Stock_Option_Plans_Restricted_

Stock Option Plans - Restricted Stock Units (Details) (Restricted stock units (RSUs) [Member], USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
RSU's Outstanding, Number of Shares:
Awarded at beginning of period (in shares)	1	8
Awards granted (in shares)	1,236	0
Awards vested (in shares)	-1	-6
Awards forfeited (in shares)	-22	-1
Awarded at end of period (in shares)	1,214	1
RSUs Outstanding, Granted Fair Value Per Unit:
Awarded at beginning of period (USD per share)	$7.98	$7.98
Awards granted (USD per share)	$28.94	$0
Awards vested (USD per share)	$24.15	$7.98
Awards forfeited (USD per share)	$24.61	$7.98
Awarded at end of period (USD per share)		$7.98
2012 Equity Incentive Plan [Member]
RSU's Outstanding, Number of Shares:
Awards granted (in shares)			2,362
Awards vested (in shares)			-396
Awards forfeited (in shares)			-246
Awarded at end of period (in shares)			2,934
RSUs Outstanding, Granted Fair Value Per Unit:
Awarded at beginning of period (USD per share)			$29.57
Awards granted (USD per share)			$39.77
Awards vested (USD per share)			$30.79
Awards forfeited (USD per share)			$31.59
Awarded at end of period (USD per share)			$37.45
Unamortized stock-based compensation expense			$77,695
Average remaining vesting term			3 years 2 months 19 days

Stock_Option_Plans_Performance

Stock Option Plans - Performance Stock Units (Details) (2012 Equity Incentive Plan [Member], Performance Stock Units [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
2012 Equity Incentive Plan [Member] | Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$267
Unamortized stock-based compensation expense	$852

Stock_Option_Plans_Stock_Bonus

Stock Option Plans - Stock Bonus Awards (Details) (2012 Equity Incentive Plan [Member], Stock Bonus Awards [Member], USD $)	12 Months Ended		3 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total accrued liability	$1,771	$852
Shares of common stock issued	22
Stock-based compensation expense	$1,771	$852
Forecast [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock issued			37

Stock_Option_Plans_Employee_St

Stock Option Plans - Employee Stock Purchase Plan (Details) (ESPP 2012 Plan [Member], USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 30, 2012
Stock-based compensation:
Shares authorized for issuance (in shares)				745,000
Maximum number of additional shares to be authorized				1,490,000
Increase in common stock reserved and available for issuance ESPP	926,000	759,000
Shares issued	194	217
Weighted average price per share	$23.94	$13.07
Fair value assumptions:
Expected life (in years)	6 months
Risk-free interest rate		0.08%
Dividend yield	0.00%	0.00%	0.00%
Unamortized stock-based compensation expense	$803
Average remaining vesting term	4 months 15 days
Minimum [Member]
Fair value assumptions:
Expected life (in years)		6 months	6 months
Volatility	45.00%	38.00%	46.00%
Risk-free interest rate	0.05%		0.13%
Maximum [Member]
Fair value assumptions:
Expected life (in years)		6 months 14 days	6 months 12 days
Volatility	52.00%	40.00%	51.00%
Risk-free interest rate	0.07%		0.15%

Stock_Option_Plans_Restricted_1

Stock Option Plans - Restricted Stock (Details) (2012 Equity Incentive Plan [Member], Restricted stock [Member], USD $)	3 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in period	54
Fair value of shares granted	$2,357	$2,357
Award vesting period		4 years
Unrecognized stock-based compensation expense	$2,161	$2,161
Cliff Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	2 years

Net_Loss_per_Share_Basic_and_D

Net Loss per Share - Basic and Diluted Net Loss Per Share (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Net loss	($64,239)	($27,531)	($20,360)
Denominator:
Weighted average number of common shares used in computing basic and diluted net loss per share (in shares)	37,381	34,874	24,056
Net loss per common share
Basic and diluted net loss per share (in dollars per share)	($1.72)	($0.79)	($0.85)

Net_Loss_per_Share_Antidilutiv

Net Loss per Share - Antidilutive Common Shares (Details)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total antidilutive securities excluded from computation of earnings per share	13,561	13,709	9,776
Stock options to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total antidilutive securities excluded from computation of earnings per share	5,288	7,223	9,636
Restricted stock units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total antidilutive securities excluded from computation of earnings per share	2,934	1,214	1
Employee stock purchase plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total antidilutive securities excluded from computation of earnings per share	90	89	133
Common stock subject to repurchase [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total antidilutive securities excluded from computation of earnings per share	54	1	4
Bonus Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total antidilutive securities excluded from computation of earnings per share	37	22	0
Common stock warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total antidilutive securities excluded from computation of earnings per share	0	2	2
Convertible senior notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total antidilutive securities excluded from computation of earnings per share	5,158	5,158	0

Segment_Reporting_Revenue_by_S

Segment Reporting - Revenue by Solution (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue from External Customer [Line Items]
Revenue	$195,607	$137,931	$106,295
Privacy, protection and security [Member]
Revenue from External Customer [Line Items]
Revenue	151,291	101,083	78,979
Archiving and governance [Member]
Revenue from External Customer [Line Items]
Revenue	$44,316	$36,848	$27,316

Segment_Reporting_by_Geographi

Segment Reporting - by Geographic Area (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment reporting:
Revenue	$195,607	$137,931	$106,295
Long-lived assets	18,718	11,221
United States [Member]
Segment reporting:
Revenue	157,593	113,819	86,661
Long-lived assets	15,974	9,425
Rest of world [Member]
Segment reporting:
Revenue	38,014	24,112	19,634
Long-lived assets	$2,744	$1,796

Income_Taxes_Domestic_and_Fore

Income Taxes - Domestic and Foreign Components of Loss Before Provision for Income Taxes (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest [Abstract]
Domestic	($69,555)	($34,284)	($23,506)
Foreign	5,003	3,945	3,667
Loss before benefit from (provision for) income taxes	($64,552)	($30,339)	($19,839)

Income_Taxes_Expense_for_Incom

Income Taxes - Expense for Income Taxes (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current tax expense:
Federal	$0	$0	$0
State	121	70	30
Foreign	530	641	491
Total current	651	711	521
Deferred tax expense:
Federal	-792	0	0
State	0	0	0
Foreign	-172	-3,519	0
Total deferred	-964	-3,519	0
(Benefit from) provision for income taxes	($313)	($2,808)	$521

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of Income Tax Expense (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Tax at federal statutory rate	($21,948)	($10,315)	($6,745)
Foreign income tax rate differential	-600	-232	-262
State, net of federal benefit	-1,692	-1,130	-822
Stock compensation charges	1,304	636	1,256
SubPart F and other permanent items	2,579	1,583	1,204
Provision to return and other	3,621	937	1,074
Research and development credits	-2,052	-2,112	-1,061
Uncertain tax positions	391	617	301
Valuation allowance	18,084	7,208	5,576
(Benefit from) provision for income taxes	($313)	($2,808)	$521

Income_Taxes_Deferred_Tax_Asse

Income Taxes - Deferred Tax Assets and Liabilities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred tax assets:
Net operating loss carryforwards	$75,376	$60,280
Tax credit carryforwards	9,566	8,228
Research expenditures	2,494	3,314
Deferred revenue	11,078	13,292
Stock compensation	7,228	3,696
Fixed assets	1,516	1,262
Accruals and other	8,505	7,250
Gross deferred tax assets	115,763	97,322
Valuation allowance	-90,929	-71,052
Total deferred tax assets	24,834	26,270
Deferred tax liabilities:
Intangible assets and other	-9,613	-7,769
Interest expense on the Notes	-12,911	-16,090
Total deferred tax liabilities	-22,524	-23,859
Total net deferred tax assets	2,310	2,411
Current deferred income tax assets (included in other current assets)	3,903	4,166
Non-current deferred income tax liabilities (included in long-term liabilities)	$1,593	$1,755

Income_Taxes_Unrecognized_Tax_

Income Taxes - Unrecognized Tax Benefits (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$3,823	$2,740	$2,526
Increase in balances related to tax positions taken during the current period	524	618	357
Increase in balances related to tax positions taken during the prior period	0	517
Decrease in balances related to tax positions taken during the prior period	-87	-40	-135
Decrease in balances related to statute expirations during the current period	-31	-12	-8
Ending balance	$4,229	$3,823	$2,740

Income_Taxes_Other_Details

Income Taxes - Other (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax [Line Items]
Federal statutory income tax rate	34.00%	34.00%	34.00%
Valuation allowance increase (decrease)	$19,877	$2,400	$3,700
Accrued interest and penalties	9	8
Liability recorded on interest and penalties	242	233
Uncertain tax benefits that would affect effective tax rate if recognized	1,432	1,541		0
Foreign withholdings	200
Undistributed earnings of foreign subsidiaries	4,000
Estimated additional tax liability if foreign undistributed earnings were repatriated	550
Federal [Member]
Income Tax [Line Items]
Operating loss carryforwards	284,974	187,700
Operating loss carryforwards, benefit recognized	84,125	34,500
State [Member]
Income Tax [Line Items]
Operating loss carryforwards	183,913	146,400
Operating loss carryforwards, benefit recognized	44,407	11,700
Foreign [Member]
Income Tax [Line Items]
Operating loss carryforwards		3,900
Research tax credit carryforward [Member] | Federal [Member]
Income Tax [Line Items]
Tax credit carryforward	5,071	4,200
Research tax credit carryforward [Member] | State [Member]
Income Tax [Line Items]
Tax credit carryforward	7,080	5,900
Research tax credit carryforward [Member] | Foreign [Member]
Income Tax [Line Items]
Tax credit carryforward	2,878	2,700
Nexgate [Member] | Foreign deferred tax asset, change in valuation allowance [Member]
Income Tax [Line Items]
Valuation allowance increase (decrease)	-792
NetCitadel [Member] | Convertible debt [Member]
Income Tax [Line Items]
Valuation allowance increase (decrease)	$2,023