A10 Networks (ATEN) 10-Q 6 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	1-May-15
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	ATEN
Entity Registrant Name	A10 Networks, Inc.
Entity Central Index Key	1580808
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		61,617,622

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Current Assets:
Cash and cash equivalents	$85,570	$91,905
Accounts receivable, net of allowances of $2,775 and $3,246 as of March 31, 2015 and December 31, 2014	52,762	54,003
Inventory	19,768	20,701
Prepaid expenses and other current assets	4,200	4,732
Total current assets	162,300	171,341
Property and equipment, net	9,951	10,780
Other long-term assets	4,695	4,859
Total Assets	176,946	186,980
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable	7,989	8,994
Accrued liabilities	19,850	22,435
Deferred revenue, current	40,155	39,256
Total current liabilities	67,994	70,685
Deferred revenue, non-current	19,505	17,964
Other non-current liabilities	1,557	1,766
Total Liabilities	89,056	90,415
Commitments and contingencies
Stockholders' Equity:
Common stock, par value $0.00001 — 500,000 shares authorized as of March 31, 2015 and December 31, 2014; 61,593 and 61,377 shares issued and outstanding as of March 31, 2015 and December 31, 2014	1	1
Additional paid-in capital	283,408	278,349
Accumulated deficit	-195,519	-181,785
Total Stockholders' Equity	87,890	96,565
Total Liabilities And Stockholders' Equity	$176,946	$186,980

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$2,775	$3,246
Common Stock, Par or Stated Value Per Share	$0.00	$0.00
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	61,593,000	61,377,000
Common stock, shares outstanding	61,593,000	61,377,000

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenue:
Products	$30,516	$36,417
Services	13,501	9,328
Total revenue	44,017	45,745
Cost of revenue:
Products	7,063	7,427
Services	3,723	2,626
Total cost of revenue	10,786	10,053
Gross profit	33,231	35,692
Operating expenses:
Sales and marketing	24,522	21,563
Research and development	14,309	11,205
General and administrative	7,527	5,363
Litigation expense	445	1,846
Total operating expenses	46,803	39,977
Loss from operations	-13,572	-4,285
Other income (expense), net:
Interest expense	-127	-587
Interest income and other income (expense), net	27	-25
Total other income (expense), net	-100	-612
Loss before provision for income taxes	-13,672	-4,897
Provision for income taxes	62	205
Net loss	-13,734	-5,102
Accretion of redeemable convertible preferred stock dividend	0	-1,150
Net loss attributable to common stockholders	($13,734)	($6,252)
Net loss per share attributable to common stockholders:
Basic (in dollars per share)	($0.22)	($0.45)
Diluted (in dollars per share)	($0.22)	($0.45)
Weighted-average shares used in computing net loss per share attributable to common stockholders:
Basic (in shares)	61,485	13,940
Diluted (in shares)	61,485	13,940

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net loss	($13,734)	($5,102)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,489	2,247
Stock-based compensation	4,633	1,770
Provision for doubtful accounts and sales returns	144	263
Unrealized foreign exchange gain	-162	-178
Changes in operating assets and liabilities:
Accounts receivable, net	1,311	-1,241
Inventory	185	-1,785
Prepaid expenses and other assets	709	-2,277
Accounts payable	-987	-341
Accrued liabilities	-2,639	870
Deferred revenue	2,438	2,714
Other	115	89
Net cash used in operating activities	-5,498	-2,971
Cash flows from investing activities:
Purchases of property and equipment	-901	-2,022
Net cash used in investing activities	-901	-2,022
Cash flows from financing activities:
Proceeds from initial public offering, net of offering costs	0	124,177
Principal payments on revolving credit facility	0	-20,000
Proceeds from Issuance of Common Stock	-64	-2,248
Other	0	-76
Net cash provided by financing activities	64	106,349
Net increase (decrease) in cash and cash equivalents	-6,335	101,356
Cash and cash equivalents—beginning of period	91,905
Cash and cash equivalents—end of period	85,570	122,149
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Inventory transfers to property and equipment	747	1,416
Costs related to the initial public offering included in accounts payable and accrued liabilities	0	1,429
Accretion of Series D redeemable convertible preferred stock	$0	$1,150

Description_of_Business_and_Su

Description of Business and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Significant Accounting Policies	Description of Business and Summary of Significant Accounting Policies
	Description of Business
	A10 Networks, Inc. (together with our subsidiaries, the “Company”, “we”, “our” or “us”) was incorporated in
	California in 2004 and reincorporated in Delaware in March 2014. We are headquartered in San Jose, California and have wholly-owned subsidiaries throughout the world including Asia and Europe. Our solutions enable enterprises, service providers, Web giants and government organizations to accelerate, secure and optimize the performance of their data center applications and networks. We currently offer three software based advanced application networking solutions. These are Application Delivery Controllers, or ADCs, to optimize data center performance; Carrier Grade Network Address Translation, or CGN, to provide address and protocol translation services for service provider networks; and a Distributed Denial of Service Threat Protection System, or TPS, for network-wide security protection. We deliver these solutions both on optimized hardware appliances and as virtual appliances across our Thunder Series and AX Series product families.
	Basis of Presentation
	The accompanying unaudited condensed consolidated financial statements include the accounts of A10 Networks, Inc., and our wholly owned subsidiaries. All inter-company balances and transactions have been eliminated in consolidation.
	We had no comprehensive income (loss) other than our net income (loss), hence our comprehensive income (loss) is the same as the net income (loss) for all periods presented. Pursuant to the accounting guidance provided by Accounting Standard Codification ("ASC") 220 Comprehensive Income, we did not present statements of comprehensive income (loss) for the periods presented.
	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and following the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain notes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as our annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments that are necessary for a fair statement of our financial information. The results of operations for the three months ended March 31, 2015 are not necessarily indicative of the results to be expected for the year ending December 31, 2015 or for any other interim period or for any other future year. The balance sheet as of December 31, 2014 has been derived from audited financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements.
	The accompanying unaudited condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements for the year ended December 31, 2014, which are included in the Annual Report on Form 10-K filed with the SEC on March 11, 2015.
	Use of Estimates
	The preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires us to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Those estimates and assumptions affect revenue recognition and deferred revenue, allowance for doubtful accounts, sales return reserve, valuation of inventory, contingencies and litigation, and determination of fair value of stock-based compensation. These estimates are based on information available as of the date of the condensed consolidated financial statements; therefore, actual results could differ from management’s estimates.
	Summary of Significant Accounting Policies
	There have been no changes to the significant accounting policies described in the 2014 Annual Report on Form 10-K that have had a material impact on our condensed consolidated financial statements and related notes.
	Concentration of Credit Risk and Significant Customers
	Financial instruments that potentially subject us to concentrations of credit risk consist of cash, cash equivalents and accounts receivable. Our cash and cash equivalents are invested in high-credit quality financial instruments with banks and financial institutions. Management believes that the financial institutions that hold our cash and cash equivalents are financially sound and, accordingly, are subject to minimal credit risk. Such deposits may be in excess of insured limits provided on such deposits.
	Our accounts receivable are unsecured and represent amounts due to us based on contractual obligations of our customers. We mitigate credit risk in respect to accounts receivable by performing periodic credit evaluations of our customers to assess the probability of accounts receivable collection based on a number of factors, including past transaction experience with the customer, evaluation of their credit history, limiting the credit extended and review of the invoicing terms of the contract. We generally do not require our customers to provide collateral to support accounts receivable.
	Significant customers, including distribution channel partners and direct customers, are those which represent more than 10% of our total revenue for each period presented or our gross accounts receivable balance as of each respective balance sheet date. Revenue from our significant customers as a percentage of our total revenue for the three months ended March 31, 2015 and 2014 are as follows:
		Three Months Ended
		March 31,
	Customers	2015	2014
	Customer A	*	20%
	Customer B	*	14%
	Customer C	*	11%
	* represents less than 10% of total revenue
	As of March 31, 2015 and December 31, 2014, no customer accounted for 10% or more of our total gross accounts receivable.
	Recent Accounting Pronouncements
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which provides new guidance on the recognition of revenue and states that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This standard will be effective for annual reporting periods beginning after December 15,2016, including interim periods within that reporting period. Early application is not permitted, however, in April 2015, the FASB tentatively proposed a one-year deferral of the effective date. If the proposed deferral is approved, the new standard will become effective for us in the first quarter of fiscal 2018. We are currently evaluating the impact of the adoption of this accounting standard update on our consolidated financial position or results of operations.
	There have been no recent accounting pronouncements or changes in accounting pronouncements during the three months ended March 31, 2015, as compared to the recent accounting pronouncements described in our Annual Report on Form 10-K for the year ended December 31, 2014 filed with SEC on March 11, 2015, that are of significance or potential significance to us.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements
	Our financial instruments consist of cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities. Cash equivalents are stated at amortized cost, which approximates fair value as of the balance sheet dates, due to the short period of time to maturity. Accounts receivable, accounts payable and accrued expenses are stated at their carrying value, which approximates fair value due to the short time to the expected receipt or payment.
	Cash and cash equivalents are carried at fair value. Our money market funds are classified within Level I of the fair value hierarchy, as these instruments are valued using quoted market prices. Specifically, we value our investments in money market securities and certificates of deposit based on quoted market prices in active markets. As of March 31, 2015 and December 31, 2014, we had no assets or liabilities classified within Level II or Level III and there were no transfers of instruments between Level I, Level II and Level III regarding fair value measurement.
	The following table sets forth the fair value of our financial assets measured on a recurring basis, by level, within the fair value hierarchy (in thousands):
		31-Mar-15				31-Dec-14
		Level I		Total		Level I		Total
	Financial Assets
	Money market funds	$	41,054	$	41,054	$	51,047	$	51,047
	We did not have realized gains or losses for the three months ended March 31, 2015 and 2014 related to our financial assets.

Balance_Sheet_Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2015
Property, Plant and Equipment [Abstract]
Balance Sheet Components	Balance Sheets and Statement of Operations Components
	Inventory
	Components of inventory as of March 31, 2015 and December 31, 2014 are shown below (in thousands):
		March 31,			December 31,
		2015			2014
	Raw materials	$	7,901		$	9,922
	Finished goods	11,867			10,779
	Total inventory	$	19,768		$	20,701
	Property and Equipment, Net
	Components of property and equipment, net as of March 31, 2015 and December 31, 2014 are shown below (in thousands):
		March 31,			December 31,
		2015			2014
	Equipment	$	31,692		$	30,486
	Software	3,190			3,197
	Furniture and fixtures	1,950			860
	Leasehold improvements	860			1,780
	Construction in progress	340			201
	Property and equipment, gross	38,032			36,524
	Less: accumulated depreciation and amortization	(28,081		)	(25,744		)
	Total property and equipment, net	$	9,951		$	10,780
	Depreciation and amortization on our property and equipment for the three months ended March 31, 2015 and 2014 was $2.5 million and $2.2 million.
	Deferred Revenue
	Deferred revenue as of March 31, 2015 and December 31, 2014 consists of the following (in thousands):
		March 31,			December 31,
		2015			2014
	Deferred revenue:
	Products	$	2,513		$	2,379
	Services	57,147			54,841
	Total deferred revenue	59,660			57,220
	Less: current portion	(40,155		)	(39,256		)
	Long-term portion	$	19,505		$	17,964
	Accrued Liabilities
	Accrued liabilities as of March 31, 2015 and December 31, 2014 consists of the following (in thousands):
		March 31,			December 31,
		2015			2014
	Accrued compensation and benefits	$	13,184		$	14,447
	Accrued tax liabilities	2,309			2,554
	Other	4,357			5,434
	Total accrued liabilities	$	19,850		$	22,435

Credit_Facility

Credit Facility	3 Months Ended
	Mar. 31, 2015
Line of Credit Facility [Abstract]
Credit Facility	Credit Facility
	In September 2013, we entered into a credit agreement with Royal Bank of Canada, JPMorgan Chase Bank, N.A. and Bank of America, N.A. as lenders. The credit agreement provides a three-year $35.0 million revolving credit facility, which includes a maximum $10.0 million letter of credit facility. As of March 31, 2015, we have no outstanding borrowings under this credit facility.
	Our obligations under the credit agreement are secured by a security interest on substantially all of our assets, including our intellectual property. The credit agreement contains customary financial and non-financial covenants, and are described in Note 4, Credit Facility of the Notes to Consolidated Financial Statements of our Annual Report on Form 10-K for the year ended December 31, 2014 filed with the SEC on March 11, 2015. We were in compliance with all financial and nonfinancial covenants under the revolving credit facility as of March 31, 2015.
	At our option, the revolving credit facility bears interest at a rate per annum based on either (i) an alternate base rate plus a margin ranging from 1.75% to 2.50% depending on our total leverage ratio, or (ii) the London interbank offered rate, or LIBOR, based on one, two, three or six month interest periods plus a margin ranging from 2.75% to 3.50% depending on our total leverage ratio. The alternate base rate is equal to the greatest of (i) the Royal Bank of Canada’s prime rate, (ii) the federal funds rate plus a margin equal to 0.50% and (iii) the Eurodollar rate for a one month interest period plus a margin equal to 1.00%.
	In addition, we incurred $1.0 million of debt issuance costs that were directly attributable to the issuance of this revolving credit facility which will be amortized to interest expense over the three-year term of this credit facility. As of March 31, 2015, the unamortized debt issuance costs of $0.4 million were included within other long-term assets in our Condensed Consolidated Balance Sheets. We are also required to pay quarterly facility fees of 0.45% per annum on the average daily unused portion of the revolving credit facility.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Legal Proceedings
	From time to time, we may be party or subject to various legal proceedings and claims, either asserted or unasserted, which arise in the ordinary course of business, including proceedings and claims that relate to intellectual property matters. Some of these proceedings involve claims that are subject to substantial uncertainties and unascertainable damages. Accordingly, except as disclosed, we have not established reserves or ranges of possible loss related to these proceedings, as at this time in the proceedings, if any, the matters do not relate to a probable loss and/or amounts cannot be reasonably estimated.
	In November 2013, Parallel Networks, LLC (“Parallel Networks”), which we believe is a non-practicing patent holding company, filed a lawsuit against us in the United States District Court for the District of Delaware. In the lawsuit, Parallel Networks alleges that our AX and Thunder series products infringe two of their U.S. patents. Parallel Networks is seeking injunctive relief, damages and attorneys’ fees and costs. Parallel Networks has asserted similar claims against a number of our competitors. The separate trials for each defendant in these related actions are set to commence in June 2016 in accordance with an order to be set forth in a trial sequencing conference. We intend to vigorously defend the lawsuit. We are unable to reasonably estimate a possible loss or range of possible loss if any, in regards to this matter; therefore, no accrued litigation expense has been recorded in the accompanying Condensed Consolidated Balance Sheets.
	On January 29, 2015, the Company, the members of our Board of Directors, our Chief Financial Officer, and the underwriters of our March 21, 2014, initial public offering were named as defendants in a putative class action lawsuit filed in the Superior Court of the State of California, County of Santa Clara, captioned City of Warren Police and Fire Retirement System v. A10 Networks, Inc., et al., 1-15-CV-276207.  Several substantially identical lawsuits were subsequently filed in the same court, bringing the same claims against the same defendants, captioned Arkansas Teacher Retirement System v. A10 Networks, Inc., et al., 1-15-CV-278575 (filed March 25, 2015) and Kaveny v. A10 Networks, Inc., et al., 1-15-CV-279006 (filed April 6, 2015).  The complaints seek to allege violations of the federal Securities Act of 1933 on behalf of a putative class consisting of purchasers of our common stock pursuant or traceable to the registration statement and prospectus for the initial public offering, and seek unspecified compensatory damages and other relief. We intend to vigorously defend these lawsuits. Based on information currently available, we are unable to reasonably estimate a possible loss or range of possible loss, if any, in regards to these lawsuits; therefore, no accrued liabilities has been recorded in the accompanying Condensed Consolidated Balance Sheets.
	Lease Obligations and Other Commitments
	Commencing in 2012, we entered into an equipment financing arrangement with a financial institution whereby the financial institution purchases and leases to us, equipment (primarily computer and network-related) for use in our business. Amounts financed under the leases are accounted for as capital leases. We financed $0.8 million under the arrangement in 2012, which was fully repaid by December 2014. In March 2015, we entered into an agreement to lease an additional $0.3 million of equipment under this financing arrangement. The anticipated delivery date of the leased equipment is in the second quarter of 2015. As of March 31, 2015 and December 31, 2014, we had no outstanding borrowings under this financing arrangement.
	We lease various operating spaces in the United States, Asia, and Europe under noncancelable operating lease arrangements that expire on various dates through February 2020. These arrangements require us to pay certain operating expenses, such as taxes, repairs, and insurance and contain renewal and escalation clauses. We recognize rent expense under these arrangements on a straight-line basis over the term of the lease.
	We have entered into agreements with some of our customers and channel partners that contain indemnification provisions in the event of claims alleging that our products infringe the intellectual property rights of a third party. Other guarantees or indemnification arrangements include guarantees of product and service performance and standby letters of credit for lease facilities and corporate credit cards. We have not recorded a liability related to these indemnification and guarantee provisions and our guarantees and indemnification arrangements have not had any significant impact on our consolidated financial statements to date.

Equity_Award_Plans

Equity Award Plans	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity Award Plans	Equity Award Plans
	Equity Incentive Plans
	2014 Equity Incentive Plan
	Our 2014 Equity Incentive Plan (the "2014 Plan") was adopted by our Board of Directors and approved by our stockholders in March 2014. The 2014 Plan provides for the granting of stock options, restricted stock awards, restricted stock units, stock appreciation rights, performance units and performance shares to our employees, directors and consultants.
	As of December 31, 2014, we had 1,343,743 shares available for future grant. Pursuant to the provisions of the 2014 Plan, on the first day of each fiscal year, starting with January 1, 2015, the number of shares in the reserve will increase by the least of (i) 8,000,000 shares, (ii) 5% of the outstanding shares of common stock on the last day of our immediately preceding fiscal year, or (iii) such other amount as determined by our Board of Directors. In January 2015, we increased common stock reserved for issuance by 3,078,645 shares in accordance with the provisions of the 2014 Plan. During the three months ended March 31, 2015, we granted 148,500 stock options and 376,280 RSUs under the 2014 Plan to our employees and consultants. As of March 31, 2015, we have 4,270,990 shares available for future grant.
	2014 Employee Stock Purchase Plan
	The 2014 Employee Stock Purchase Plan (the "2014 Purchase Plan") was adopted by our Board of Directors and approved by our stockholders in March 2014.
	As of December 31, 2014, we had 1,031,316 shares available for future purchase. Under the provisions of the 2014 Purchase Plan, on the first day of each fiscal year, starting with January 1, 2015, the number of shares in the reserve will increase by the lesser of (i) 3,500,000 shares, (ii) 1% of the outstanding shares of our common stock on the last day of the immediately preceding fiscal year, or (iii) such other amount as determined by our Board of Directors or other committee administering the 2014 Purchase Plan. In January 2015, we increased common shares reserved for future purchase by 615,729 shares in accordance with the provision of the 2014 Purchase Plan. There was no purchases under the 2014 Purchase Plan during the three months ended March 31, 2015. As of March 31, 2015, we have 1,647,045 shares available for future purchase.
	Stock-based Compensation
	Stock-based compensation is based on the estimated fair value of awards, net of estimated forfeitures, and recognized over the requisite service period. The following is a summary of stock-based compensation for stock-based awards granted under the 2014 Plan, the 2008 Plan, and employee stock purchases under the 2014 Purchase Plan recognized during the three months ended March 31, 2015 and 2014 (in thousands):
		Three Months Ended March 31,
		2015				2014
	Stock-based compensation by type of award:
	Stock options	$	1,477			$	1,685
	Restricted stock units	1,934				—
	Employee stock purchase plan	1,222				85
	Total stock-based compensation	$	4,633			$	1,770
	Stock-based compensation by category of expense:
	Cost of revenue	$	471			$	85
	Sales and marketing	2,066				884
	Research and development	1,585				463
	General and administrative	511				338
		$	4,633			$	1,770
	At March 31, 2015, we had $30.7 million of unrecognized stock-based compensation expense, net of estimated forfeitures, related to stock options, unvested restricted stock units and 2014 Stock Purchase Plan grants which will be recognized over a weighted-average period of 2.6 years.
	Determination of Fair Value
	We use the Black-Scholes option pricing model to determine the grant date fair value of stock options and stock purchases and recognize stock-based compensation expense on a straight-line basis over the requisite service period.
	The determination of the fair value on the date of grant is affected by the estimated underlying common stock price, as well as assumptions regarding a number of complex and subjective variables. These variables include expected stock price volatility over the term of the awards, actual and projected employee stock option exercise behaviors, risk-free interest rates, and expected dividends.
	The fair value of each grant of stock options was determined using the Black-Scholes option pricing model and assumptions discussed below. Each of these inputs is subjective and generally requires significant judgment to determine.
	• Expected Term. We estimate the expected life of options based on an analysis of our historical experience of employee exercise and post-vesting termination behavior considered in relation to the contractual life of the option. The expected term for the 2014 Purchase Plan is based on the term of the purchase period.
	• Risk-Free Interest Rate. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for zero coupon U.S. Treasury notes with maturities approximately equal to the expected terms of stock options and shares to be issued under the 2014 Purchase Plan.
	• Expected Volatility. Due to the limited trading history of our own common stock, we determined the share price volatility factor based on a combination of the historical volatility of our own common stock and the historical volatility of our peer group.
	• Dividend Rate. The expected dividend was assumed to be zero as we have never paid dividends and have no current plans to do so.
	Stock Option Activity
	The following table summarizes our stock option activity and related information as of and for the three months ended March 31, 2015 (in thousands, except for years and per share amounts):
			Number of Shares Underlying Outstanding Options			Weighted-Average Exercise Price			Weighted-Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value
	Outstanding as of December 31, 2014		11,084			$	5.18		7.9
	Granted		149			$	4.67
	Exercised		(166	)		$	1.59
	Canceled		(415	)		$	7.32
	Outstanding as of March 31, 2015		10,652			$	5.15		7.6		$	7,521
	Vested and expected to vest as of March 31, 2015		10,091			$	5.1		7.5		$	7,518
	Vested and exercisable as of March 31, 2015		5,118			$	3.97		6.2		$	7,368
	The aggregate intrinsic value represents the difference between the closing stock price of our common stock on March 31, 2015 compared to the exercise price of the outstanding in-the-money options.
	The following table provides information pertaining to our stock options for the three months ended March 31, 2015 and 2014 (in thousands, except weighted-average fair values):
		Three Months Ended March 31,
		2015				2014
	Total fair value of options granted	$	305			$	7,071
	Weighted average fair value of options granted	$	2.05			$	5.97
	Intrinsic value of options exercised	$	537			$	6,692
	The estimated grant-date fair value of our equity-based awards issued to employees was calculated using the Black-
	Scholes option-pricing model, based on the following assumptions:
		Three Months Ended March 31,
		2015		2014
	Expected term (in years)	4.8		5.5
	Risk-free interest rate	1.41%		1.73%
	Expected volatility	51%		47%
	Dividend rate	—%		—%
	Restricted Stock Units Activity
	We have granted time-based restricted stock units ("RSU") to our employees, directors and consultants and market performance-based restricted stock units ("MSU") to certain executive officers.
	Time-based Restricted Stock Units
	A summary of RSU activities for the three months ended March 31, 2015, is as follows (in thousands, except years and per share amounts):
		Number of Shares			Weighted Average Grant Date Fair Value			Weighted Average Remaining Contractual Life		Aggregated Intrinsic Value
	Outstanding as of December 31, 2014	2,388			$	8.97
	Granted	376			$	4.61
Released	(18	)		$	10.58
Canceled	(168	)		$	9.27
Outstanding as of March 31, 2015	2,578			$	8.3		1.5		$	11,161
The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value (calculated by multiplying our closing stock price on the last trading day of the period by the number of unvested RSUs) that would have been received by the unit holders had all RSUs been vested and released on March 31, 2015. This amount will fluctuate based on the fair market value of our stock.
Market Performance-based Restricted Stock Units
We granted MSUs covering 540,000 shares of our common stock to our executive officers during 2014, all of which were outstanding as of March 31, 2015. These MSUs will vest if the closing price of our common stock remains above certain predetermined target prices for 20 consecutive trading days within a 4-year period following the award’s grant date, subject to continued service by the award holder.
The total aggregate intrinsic value for the MSUs granted was $2.4 million, which represents the total pre-tax intrinsic value (calculated by multiplying our closing stock price on the last trading day of period by the number of unvested MSUs) that would have been received by the award holders had all MSUs vested and been released on March 31, 2015. This amount will fluctuate based on the fair market value of our stock. No MSUs were vested or released during the three months ended March 31, 2015.
Employee Stock Purchase Plan
The fair value of the option component of the 2014 Purchase Plan shares was estimated at the grant date using the Black-Scholes option pricing model with the following weighted average assumptions:
	Three Months Ended March 31,
	2015		2014
Expected term (in years)	n/a		1.42
Risk-free interest rate	n/a		2.14%
Expected volatility	n/a		31.00%
Dividend rate	n/a		—%
* There were no stock purchase rights granted under the 2014 Purchase Plan during the three months ended March 31, 2015.

Net_Income_Per_Share_Available

Net Income Per Share Available Loss Attributable To Common Stockholders	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Net Income Per Share Available (Loss Attributable) To Common Stockholders	Net Income Per Share Available (Loss Attributable) To Common Stockholders
	The following table sets forth the computation of our basic and diluted net loss per share attributable to common stockholders (in thousands, except per share data):
		Three Months Ended March 31,
		2015				2014
	Basic and diluted net loss per share attributable to common stockholders
	Numerator:
	Net loss attributable to common stockholders	$	(13,734	)		$	(6,252	)
	Denominator:
	Weighted-average shares outstanding - basic	61,485				13,940
	Effect of dilutive potential common shares from stock options and restricted stock units	—				—
	Weighted-average shares outstanding - diluted	61,485				13,940
	Net loss per share attributable to common stockholders:
	Basic and diluted	$	(0.22	)		$	(0.45	)
	The following weighted average outstanding shares of common stock equivalents were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been antidilutive (in thousands):
		Three Months Ended March 31,
		2015			2014
	Stock options, restricted stock units and employee stock purchase plan	11,318			9,936
	Common stock subject to repurchase	117			342
		11,435			10,278

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	We recorded income tax expense of $0.1 million and $0.2 million for the three months ended March 31, 2015 and 2014, which was primarily comprised of foreign taxes. Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the carrying amounts of existing assets and liabilities in the financial statements and their respective tax bases using tax rates expected to be in effect during the years in which the basis differences reverse.
	We believe it is more likely than not that our federal and state net deferred tax assets will not be fully realized. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of a deferred tax asset will be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. A valuation allowance is recorded for loss carryforwards and other deferred tax assets where it is more likely than not that such deferred tax assets will not be realized. Accordingly, we continue to maintain a valuation allowance against all of our net deferred tax assets as of March 31, 2015. Due to historic losses in the U.S., we have a full valuation allowance on the U.S. federal and state deferred tax assets. We will continue to maintain a full valuation allowance against our net federal, state and certain foreign deferred tax assets until there is sufficient evidence to support recoverability of our deferred tax assets.
	We had $2.3 million and $2.2 million of unrecognized tax benefits as of March 31, 2015 and December 31, 2014.  We do not anticipate a material change to our unrecognized tax benefits over the next twelve months. Unrecognized tax benefits may change during the next twelve months for items that arise in the ordinary course of business.
	Accrued interest and penalties related to unrecognized tax benefits are recognized as part of our income tax provision in the Condensed Consolidated Statements of Operations.  All tax years remain open and are subject to future examinations by federal, state and foreign tax authorities. We are not under examination in any jurisdiction.

Segment_Information

Segment Information	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Segment Information	Segment Information
	Our chief operating decision maker is our Chief Executive Officer who reviews financial information presented on a consolidated basis, accompanied by disaggregated information about revenue by geographic region for purposes of allocating resources and evaluating financial performance. Accordingly, we have a single reportable segment and operating segment structure.
	The following table represents revenue by geographic areas based on customers' location, as determined by their ship to addresses (in thousands):
		Three Months Ended March 31,
		2015		2014
	United States	$	22,858	$	18,212
	Japan	8,840		17,305
	Asia Pacific, excluding Japan	4,586		4,304
	EMEA	6,225		4,140
	Other	1,508		1,784
	Total revenue	$	44,017	$	45,745
	No other country outside of the United States and Japan comprised 10% or greater of our revenue for the three months ended March 31, 2015 and 2014.
	Geographical information relating to our long-lived assets which include property and equipment, net and intangible assets, net as of March 31, 2015 and December 31, 2014 was as follows (in thousands):
		March 31,		December 31,
		2015		2014
	United States	$	9,076	$	9,702
	Japan	179		247
	Asia Pacific, excluding Japan	1,564		1,724
	EMEA	103		104
	Total property and equipment, net and intangible assets, net	$	10,922	$	11,777

RelatedParty_Transactions

Related-Party Transactions	3 Months Ended
	Mar. 31, 2015
Related Party Transactions [Abstract]
Related-Party Transactions	Related-Party Transactions
	An affiliate of one of our significant stockholders is also acting as a reseller of our products. During the three months ended March 31, 2015 and 2014, we recognized $1.4 million and $0.6 million total revenue from this reseller.
	We had gross accounts receivable of $0.8 million and $0.4 million from this reseller as of March 31, 2015 and December 31, 2014.

Description_of_Business_and_Su1

Description of Business and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business
	A10 Networks, Inc. (together with our subsidiaries, the “Company”, “we”, “our” or “us”) was incorporated in
	California in 2004 and reincorporated in Delaware in March 2014. We are headquartered in San Jose, California and have wholly-owned subsidiaries throughout the world including Asia and Europe. Our solutions enable enterprises, service providers, Web giants and government organizations to accelerate, secure and optimize the performance of their data center applications and networks. We currently offer three software based advanced application networking solutions. These are Application Delivery Controllers, or ADCs, to optimize data center performance; Carrier Grade Network Address Translation, or CGN, to provide address and protocol translation services for service provider networks; and a Distributed Denial of Service Threat Protection System, or TPS, for network-wide security protection. We deliver these solutions both on optimized hardware appliances and as virtual appliances across our Thunder Series and AX Series product families
Basis of Presentation	Basis of Presentation
	The accompanying unaudited condensed consolidated financial statements include the accounts of A10 Networks, Inc., and our wholly owned subsidiaries. All inter-company balances and transactions have been eliminated in consolidation.
	We had no comprehensive income (loss) other than our net income (loss), hence our comprehensive income (loss) is the same as the net income (loss) for all periods presented. Pursuant to the accounting guidance provided by Accounting Standard Codification ("ASC") 220 Comprehensive Income, we did not present statements of comprehensive income (loss) for the periods presented.
	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and following the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain notes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as our annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments that are necessary for a fair statement of our financial information. The results of operations for the three months ended March 31, 2015 are not necessarily indicative of the results to be expected for the year ending December 31, 2015 or for any other interim period or for any other future year. The balance sheet as of December 31, 2014 has been derived from audited financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements.
	The accompanying unaudited condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements for the year ended December 31, 2014, which are included in the Annual Report on Form 10-K filed with the SEC on March 11, 2015.
Use of Estimates	Use of Estimates
	The preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires us to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Those estimates and assumptions affect revenue recognition and deferred revenue, allowance for doubtful accounts, sales return reserve, valuation of inventory, contingencies and litigation, and determination of fair value of stock-based compensation. These estimates are based on information available as of the date of the condensed consolidated financial statements; therefore, actual results could differ from management’s estimates.
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies
	There have been no changes to the significant accounting policies described in the 2014 Annual Report on Form 10-K that have had a material impact on our condensed consolidated financial statements and related notes.
Concentration of Credit Risk and Significant Customers	Concentration of Credit Risk and Significant Customers
	Financial instruments that potentially subject us to concentrations of credit risk consist of cash, cash equivalents and accounts receivable. Our cash and cash equivalents are invested in high-credit quality financial instruments with banks and financial institutions. Management believes that the financial institutions that hold our cash and cash equivalents are financially sound and, accordingly, are subject to minimal credit risk. Such deposits may be in excess of insured limits provided on such deposits.
	Our accounts receivable are unsecured and represent amounts due to us based on contractual obligations of our customers. We mitigate credit risk in respect to accounts receivable by performing periodic credit evaluations of our customers to assess the probability of accounts receivable collection based on a number of factors, including past transaction experience with the customer, evaluation of their credit history, limiting the credit extended and review of the invoicing terms of the contract. We generally do not require our customers to provide collateral to support accounts receivable.
	Significant customers, including distribution channel partners and direct customers, are those which represent more than 10% of our total revenue for each period presented or our gross accounts receivable balance as of each respective balance sheet date.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which provides new guidance on the recognition of revenue and states that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This standard will be effective for annual reporting periods beginning after December 15,2016, including interim periods within that reporting period. Early application is not permitted, however, in April 2015, the FASB tentatively proposed a one-year deferral of the effective date. If the proposed deferral is approved, the new standard will become effective for us in the first quarter of fiscal 2018. We are currently evaluating the impact of the adoption of this accounting standard update on our consolidated financial position or results of operations.
	There have been no recent accounting pronouncements or changes in accounting pronouncements during the three months ended March 31, 2015, as compared to the recent accounting pronouncements described in our Annual Report on Form 10-K for the year ended December 31, 2014 filed with SEC on March 11, 2015, that are of significance or potential significance to us.

Description_of_Business_and_Su2

Description of Business and Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Revenue as Percentage of Total Revenue and Accounts Receivable as Percentage of Total Net Accounts Receivable	Revenue from our significant customers as a percentage of our total revenue for the three months ended March 31, 2015 and 2014 are as follows:
		Three Months Ended
		March 31,
	Customers	2015	2014
	Customer A	*	20%
	Customer B	*	14%
	Customer C	*	11%
	* represents less than 10% of total revenue

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets Measured on Recurring Basis	The following table sets forth the fair value of our financial assets measured on a recurring basis, by level, within the fair value hierarchy (in thousands):
		31-Mar-15				31-Dec-14
		Level I		Total		Level I		Total
	Financial Assets
	Money market funds	$	41,054	$	41,054	$	51,047	$	51,047

Balance_Sheet_Components_Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2015
Property, Plant and Equipment [Abstract]
Schedule of Inventory	Components of inventory as of March 31, 2015 and December 31, 2014 are shown below (in thousands):
		March 31,			December 31,
		2015			2014
	Raw materials	$	7,901		$	9,922
	Finished goods	11,867			10,779
	Total inventory	$	19,768		$	20,701
Schedule of Property and Equipment, Net	Components of property and equipment, net as of March 31, 2015 and December 31, 2014 are shown below (in thousands):
		March 31,			December 31,
		2015			2014
	Equipment	$	31,692		$	30,486
	Software	3,190			3,197
	Furniture and fixtures	1,950			860
	Leasehold improvements	860			1,780
	Construction in progress	340			201
	Property and equipment, gross	38,032			36,524
	Less: accumulated depreciation and amortization	(28,081		)	(25,744		)
	Total property and equipment, net	$	9,951		$	10,780
Schedule of Deferred Revenue	Deferred revenue as of March 31, 2015 and December 31, 2014 consists of the following (in thousands):
		March 31,			December 31,
		2015			2014
	Deferred revenue:
	Products	$	2,513		$	2,379
	Services	57,147			54,841
	Total deferred revenue	59,660			57,220
	Less: current portion	(40,155		)	(39,256		)
	Long-term portion	$	19,505		$	17,964
Schedule of accrued liabilities	Accrued liabilities as of March 31, 2015 and December 31, 2014 consists of the following (in thousands):
		March 31,			December 31,
		2015			2014
	Accrued compensation and benefits	$	13,184		$	14,447
	Accrued tax liabilities	2,309			2,554
	Other	4,357			5,434
	Total accrued liabilities	$	19,850		$	22,435

Equity_Award_Plans_Tables

Equity Award Plans (Tables)	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock-based Compensation	The following is a summary of stock-based compensation for stock-based awards granted under the 2014 Plan, the 2008 Plan, and employee stock purchases under the 2014 Purchase Plan recognized during the three months ended March 31, 2015 and 2014 (in thousands):
		Three Months Ended March 31,
		2015				2014
	Stock-based compensation by type of award:
	Stock options	$	1,477			$	1,685
	Restricted stock units	1,934				—
	Employee stock purchase plan	1,222				85
	Total stock-based compensation	$	4,633			$	1,770
	Stock-based compensation by category of expense:
	Cost of revenue	$	471			$	85
	Sales and marketing	2,066				884
	Research and development	1,585				463
	General and administrative	511				338
		$	4,633			$	1,770
Summary of Activity under Stock Option Plans	The following table summarizes our stock option activity and related information as of and for the three months ended March 31, 2015 (in thousands, except for years and per share amounts):
			Number of Shares Underlying Outstanding Options			Weighted-Average Exercise Price			Weighted-Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value
	Outstanding as of December 31, 2014		11,084			$	5.18		7.9
	Granted		149			$	4.67
	Exercised		(166	)		$	1.59
	Canceled		(415	)		$	7.32
	Outstanding as of March 31, 2015		10,652			$	5.15		7.6		$	7,521
	Vested and expected to vest as of March 31, 2015		10,091			$	5.1		7.5		$	7,518
	Vested and exercisable as of March 31, 2015		5,118			$	3.97		6.2		$	7,368
Stock Option Information	The following table provides information pertaining to our stock options for the three months ended March 31, 2015 and 2014 (in thousands, except weighted-average fair values):
		Three Months Ended March 31,
		2015				2014
	Total fair value of options granted	$	305			$	7,071
	Weighted average fair value of options granted	$	2.05			$	5.97
	Intrinsic value of options exercised	$	537			$	6,692
Stock Options Valuation Assumptions	The estimated grant-date fair value of our equity-based awards issued to employees was calculated using the Black-
	Scholes option-pricing model, based on the following assumptions:
		Three Months Ended March 31,
		2015		2014
	Expected term (in years)	4.8		5.5
	Risk-free interest rate	1.41%		1.73%
	Expected volatility	51%		47%
	Dividend rate	—%		—%
Summary of Restricted Stock Units Activity	A summary of RSU activities for the three months ended March 31, 2015, is as follows (in thousands, except years and per share amounts):
		Number of Shares			Weighted Average Grant Date Fair Value			Weighted Average Remaining Contractual Life		Aggregated Intrinsic Value
	Outstanding as of December 31, 2014	2,388			$	8.97
	Granted	376			$	4.61
	Released	(18	)		$	10.58
	Canceled	(168	)		$	9.27
	Outstanding as of March 31, 2015	2,578			$	8.3		1.5		$	11,161
Summary of Valuation Assumptions	The fair value of the option component of the 2014 Purchase Plan shares was estimated at the grant date using the Black-Scholes option pricing model with the following weighted average assumptions:
		Three Months Ended March 31,
		2015		2014
	Expected term (in years)	n/a		1.42
	Risk-free interest rate	n/a		2.14%
	Expected volatility	n/a		31.00%
	Dividend rate	n/a		—%
	* There were no stock purchase rights granted under the 2014 Purchase Plan during the three months ended March 31, 2015

Net_Income_Per_Share_Available1

Net Income Per Share Available Loss Attributable To Common Stockholders (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Summary of Computation of Basic and Diluted Net Loss Per Share	The following table sets forth the computation of our basic and diluted net loss per share attributable to common stockholders (in thousands, except per share data):
		Three Months Ended March 31,
		2015				2014
	Basic and diluted net loss per share attributable to common stockholders
	Numerator:
	Net loss attributable to common stockholders	$	(13,734	)		$	(6,252	)
	Denominator:
	Weighted-average shares outstanding - basic	61,485				13,940
	Effect of dilutive potential common shares from stock options and restricted stock units	—				—
	Weighted-average shares outstanding - diluted	61,485				13,940
	Net loss per share attributable to common stockholders:
	Basic and diluted	$	(0.22	)		$	(0.45	)
Summary of Outstanding Shares of Common Stock Equivalents	The following weighted average outstanding shares of common stock equivalents were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been antidilutive (in thousands):
		Three Months Ended March 31,
		2015			2014
	Stock options, restricted stock units and employee stock purchase plan	11,318			9,936
	Common stock subject to repurchase	117			342
		11,435			10,278

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Schedule of Total Revenue Based on Customer's Location	The following table represents revenue by geographic areas based on customers' location, as determined by their ship to addresses (in thousands):
		Three Months Ended March 31,
		2015		2014
	United States	$	22,858	$	18,212
	Japan	8,840		17,305
	Asia Pacific, excluding Japan	4,586		4,304
	EMEA	6,225		4,140
	Other	1,508		1,784
	Total revenue	$	44,017	$	45,745
Schedule of Long-lived Assets, Net by Location	Geographical information relating to our long-lived assets which include property and equipment, net and intangible assets, net as of March 31, 2015 and December 31, 2014 was as follows (in thousands):
		March 31,		December 31,
		2015		2014
	United States	$	9,076	$	9,702
	Japan	179		247
	Asia Pacific, excluding Japan	1,564		1,724
	EMEA	103		104
	Total property and equipment, net and intangible assets, net	$	10,922	$	11,777

Description_of_Business_and_Su3

Description of Business and Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business Incorporation, year	2004
Entity, state of incorporation	Delaware

Description_of_Business_and_Su4

Description of Business and Summary of Significant Accounting Policies - Schedule of Revenue as Percentage of Total Revenue and Accounts Receivable as Percentage of Total Net Accounts Receivable (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Customer A | Revenue
Entity Wide Revenue Major Customer [Line Items]
Percentage representation of significant customers	20.00%
Customer A | Accounts Receivable
Entity Wide Revenue Major Customer [Line Items]
Percentage representation of significant customers		0.00%	0.00%
Customer B | Revenue
Entity Wide Revenue Major Customer [Line Items]
Percentage representation of significant customers	14.00%
Customer C | Revenue
Entity Wide Revenue Major Customer [Line Items]
Percentage representation of significant customers	11.00%

Fair_Value_Measurements_Schedu

Fair Value Measurements - Schedule of Fair Value of Financial Assets (Details) (Fair Value, Measurements, Recurring, USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Financial Assets
Realized gains or losses on financial assets	$0	$0
Money Market Funds
Financial Assets
Assets at fair value	41,054,000		51,047,000
Money Market Funds | Level I
Financial Assets
Assets at fair value	$41,054,000		$51,047,000

Balance_Sheet_Components_Sched

Balance Sheet Components - Schedule of Inventory (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Property, Plant and Equipment [Abstract]
Raw materials	$7,901	$9,922
Finished goods	11,867	10,779
Total inventory	$19,768	$20,701

Balance_Sheet_Components_Sched1

Balance Sheet Components - Schedule of Property and Equipment, Net (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Property Plant And Equipment [Line Items]
Property and equipment, gross	$38,032	$36,524
Less: accumulated depreciation and amortization	-28,081	-25,744
Total property and equipment, net	9,951	10,780
Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	31,692	30,486
Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,190	3,197
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,950	860
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	860	1,780
Construction in Progress
Property Plant And Equipment [Line Items]
Property and equipment, gross	$340	$201

Balance_Sheet_Components_Sched2

Balance Sheet Components - Schedule of Deferred Revenue (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Deferred Revenue Arrangement [Line Items]
Total deferred revenue	$59,660	$57,220
Less: current portion of deferred revenue	-40,155	-39,256
Deferred revenue, non-current	19,505	17,964
Products
Deferred Revenue Arrangement [Line Items]
Total deferred revenue	2,513	2,379
Services
Deferred Revenue Arrangement [Line Items]
Total deferred revenue	$57,147	$54,841

Balance_Sheet_Components_Accru

Balance Sheet Components - Accrued Liabilities (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Property, Plant and Equipment [Abstract]
Accrued compensation and benefits	$13,184	$14,447
Accrued tax liabilities	2,309	2,554
Other	4,357	5,434
Total accrued liabilities	$19,850	$22,435

Balance_Sheet_Components_Addit

Balance Sheet Components - Additional Information (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Property, Plant and Equipment [Abstract]
Depreciation and amortization property and equipment	$2.50	$2.20

Credit_Facility_Details

Credit Facility (Details) (USD $)	1 Months Ended	3 Months Ended
	Sep. 30, 2013	Mar. 31, 2015
Revolving Credit Facility
Line of Credit Facility [Line Items]
Debt instrument term	3 years
Maximum borrowing capacity	$35,000,000
Amount outstanding		0
Debt issuance costs	1,000,000
Unamortized debt issuance costs		400,000
Quarterly facility fees		0.45%
Revolving Credit Facility | Alternate Base Rate | Minimum
Line of Credit Facility [Line Items]
Variable interest rate	1.75%
Revolving Credit Facility | Alternate Base Rate | Maximum
Line of Credit Facility [Line Items]
Variable interest rate	2.50%
Revolving Credit Facility | LIBOR | Minimum
Line of Credit Facility [Line Items]
Variable interest rate	2.75%
Revolving Credit Facility | LIBOR | Maximum
Line of Credit Facility [Line Items]
Variable interest rate	3.50%
Revolving Credit Facility | Federal Funds Rate
Line of Credit Facility [Line Items]
Variable interest rate	0.50%
Revolving Credit Facility | Eurodollar
Line of Credit Facility [Line Items]
Variable interest rate	1.00%
Letter of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$10,000,000

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2012
Loss Contingencies [Line Items]
Capital Lease Obligations	$300,000	$800,000
Parallel Networks
Loss Contingencies [Line Items]
Litigation reserve	0
Class Action Lawsuit [Member]
Loss Contingencies [Line Items]
Litigation reserve	$0

Equity_Award_Plans_Additional_

Equity Award Plans - Additional Information (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted to employees and consultants	149,000
Total compensation expense related to unvested awards granted, not yet recognized	$30,700,000
Total compensation expense related to unvested awards granted, not yet recognized weighted-average period for recognition	2 years 7 months 20 days
2014 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized	615,729
Stock Issued During Period, Shares, Employee Stock Purchase Plans	0
Number of shares available for future grant	1,647,045	1,031,316
Description of automatic increase in shares reserved for future issuance	On the first day of each fiscal year, starting with January 1, 2015, the number of shares in the reserve will increase by the least of (i) 3,500,000 shares, (ii) 1% of the outstanding shares of our common stock on the last day of the immediately preceeding fiscal year, or (iii) such other amount as determined by our board of directors
Purchase limit of 2014 ESPP description	Purchase limits of 1,500 shares during each six month purchase period or $25,000 worth of stock for each calendar year
Offering period description	Each offering period will be approximately twenty-four months in duration, starting on the first trading day on or after May 21 and November 21 of each year, except for the first offering period, which commenced on March 21, 2014 and will end on the last trading day on or before May 20, 2016
Restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted (in shares)	376,000
Aggregated Intrinsic Value	11,161,000
Market Performance-Based Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted (in shares)		540,000
Share-based Compensation Arrangement by Share-based Payment Award, Consecutive Trading Days		20 days
Share-based Compensation Arrangement by Share-based Payment Award, Target Price Measurement Period		4 years
Aggregated Intrinsic Value		$2,400,000
2014 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized	3,078,645
Options granted to employees and consultants	149,000
Number of shares available for future grant	4,270,990	1,343,743
Granted (in shares)	376,000
2014 Stock Incentive Plan | Stock options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Description of automatic increase in shares reserved for future issuance	On the first day of each fiscal year, starting with January 1, 2015, the number of shares in the reserve will increase by the least of (i) 8,000,000 shares, (ii) 5% of the outstanding shares of common stock on the last day of our immediately preceding fiscal year, or (iii) such other amount as determined by our board of directors.
Maximum | Two Thousand Fourteen Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Additional shares reserved for future issuance			8,000,000
Percentage of outstanding shares of common stock			5.00%
Maximum | 2014 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of outstanding shares of common stock			1.00%
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized			3,500,000

Equity_Award_Plans_Schedule_of

Equity Award Plans - Schedule of Stock-based Compensation Awards Granted under Stock Option Plan in Consolidated Statements of Operations (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$4,633	$1,770
Cost of revenue
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	471	85
Sales and marketing
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	2,066	884
Research and development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	1,585	463
General and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	511	338
Stock options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	1,477	1,685
Restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	1,934	0
ESPP [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$1,222	$85

Equity_Award_Plans_Summary_of_

Equity Award Plans - Summary of Activity under Stock Option Plans (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Number of shares underlying outstanding options
Outstanding options, Beginning balance	11,084
Granted (in shares)	149
Exercised (in shares)	-166
Canceled (in shares)	-415
Outstanding options, Ending balance	10,652
Vested and expected to vest at end of period	10,091
Vested and exercisable (in shares)	5,118
Options Outstanding Weighted-average exercise price
Beginning balance (in dollars per share)	$5.18
Granted (in dollars per share)	$4.67
Exercised (in dollars per share)	$1.59
Canceled (in dollars per share)	$7.32
Ending balance (in dollars per share)	$5.15
Vested and expected to vest at end of period (in dollars per share)	$5.10
Vested and exercisable at end of period (in dollars per share)	$3.97
Weighted-average remaining contractual term	7 years 7 months 6 days	7 years 10 months 24 days
Weighted average remaining contractual term, Vested and expected to vest at end of period	7 years 5 months 21 days
Weighted average remaining contractual term, Vested and exercisable at end of period	6 years 2 months 4 days
Aggregate Intrinsic Value	$7,521
Aggregate Intrinsic Value, Vested and expected to vest at end of period	7,518
Aggregate Intrinsic Value, Vested and exercisable at end of period	$7,368

Equity_Award_Plans_Information

Equity Award Plans - Information About Stock Options (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Total fair value of options granted	$305	$7,071
Weighted average fair value of options granted (in dollars per share)	$2.05	$5.97
Intrinsic value of options exercised	$537	$6,692

Equity_Award_Plans_Summary_of_1

Equity Award Plans - Summary of Valuation Assumptions (Details)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
ESPP [Member] | 2014 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)		1 year 5 months 1 day
Risk-free interest rate		2.14%
Expected volatility		31.00%
Dividend rate		0.00%
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	4 years 9 months 18 days	5 years 6 months
Risk-free interest rate	1.41%	1.73%
Expected volatility	51.00%	47.00%
Dividend rate	0.00%	0.00%

Equity_Award_Plans_Summary_of_2

Equity Award Plans - Summary of RSU activity (Details) (Restricted stock units, USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of period (in shares)	2,388,000
Granted (in shares)	376,000
Released (in shares)	-18,000
Canceled (in shares)	-168,000
Outstanding at end of period (in shares)	2,578,000
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share)	$8.97
Granted (in dollars per share)	$4.61
Released (in dollars per share)	$10.58
Canceled (in dollars per share)	$9.27
Outstanding at end of period (in dollars per share)	$8.30
Weighted Average Remaining Contractual Life	1 year 5 months 26 days
Aggregated Intrinsic Value	$11,161

Net_Income_Per_Share_Available2

Net Income Per Share Available Loss Attributable To Common Stockholders - Summary of Computation of Basic and Diluted Net Loss Per Share (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Net loss attributable to common stockholders	($13,734)	($6,252)
Weighted-average shares outstanding - basic	61,485	13,940
Effect of dilutive potential common shares from stock options and restricted stock units	0	0
Weighted-average shares outstanding - diluted	61,485	13,940
Basic and diluted (in dollars per share)	($0.22)	($0.45)

Net_Income_Per_Share_Available3

Net Income Per Share Available Loss Attributable To Common Stockholders - Summary of Outstanding Shares of Common Stock Equivalents (Details)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share Diluted [Line Items]
Anti-dilutive securities excluded from computation of diluted net income per share	11,435	10,278
Stock Options to Purchase Common Stock
Earnings Per Share Diluted [Line Items]
Anti-dilutive securities excluded from computation of diluted net income per share	11,318	9,936
Common Stock Subject to Repurchase
Earnings Per Share Diluted [Line Items]
Anti-dilutive securities excluded from computation of diluted net income per share	117	342

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income tax expense	$62,000	$205,000
Unrecognized tax benefits	$2,300,000		$2,200,000

Segment_Information_Schedule_o

Segment Information - Schedule of Total Revenue Based on Customer's Location (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Total revenue	$44,017	$45,745
United States
Segment Reporting Information [Line Items]
Total revenue	22,858	18,212
Japan
Segment Reporting Information [Line Items]
Total revenue	8,840	17,305
Asia Pacific, excluding Japan
Segment Reporting Information [Line Items]
Total revenue	4,586	4,304
EMEA
Segment Reporting Information [Line Items]
Total revenue	6,225	4,140
Other
Segment Reporting Information [Line Items]
Total revenue	$1,508	$1,784

Segment_Information_Schedule_o1

Segment Information - Schedule of Long-lived Assets, Net by Location (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Segment Reporting Information [Line Items]
Total property and equipment, net and intangible assets, net	$10,922	$11,777
United States
Segment Reporting Information [Line Items]
Total property and equipment, net and intangible assets, net	9,076	9,702
Japan
Segment Reporting Information [Line Items]
Total property and equipment, net and intangible assets, net	179	247
Asia Pacific, excluding Japan
Segment Reporting Information [Line Items]
Total property and equipment, net and intangible assets, net	1,564	1,724
EMEA
Segment Reporting Information [Line Items]
Total property and equipment, net and intangible assets, net	$103	$104

RelatedParty_Transactions_Deta

Related-Party Transactions (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Related Party Transactions [Abstract]
Revenue from related parties	$1.40	$0.60
Gross accounts receivable	$0.80		$0.40