Gigamon (GIMO) 10-Q 6 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 28, 2015	Apr. 24, 2015
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	28-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	GIMO
Entity Registrant Name	GIGAMON INC.
Entity Central Index Key	1484504
Current Fiscal Year End Date	-14
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		33,180,198

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 28, 2015	Dec. 27, 2014
In Thousands, unless otherwise specified
CURRENT ASSETS:
Cash and cash equivalents	$77,919	$38,941
Short-term investments	88,674	110,465
Accounts receivable	25,404	28,686
Inventories	4,626	6,551
Deferred tax assets	146	150
Prepaid expenses and other current assets	6,768	5,316
Total current assets	203,537	190,109
Property and equipment, net	7,105	7,387
Deferred tax assets, non-current	51	64
Other assets, non-current	436	426
TOTAL ASSETS	211,129	197,986
CURRENT LIABILITIES:
Accounts payable	1,245	2,391
Accrued liabilities	17,451	22,838
Deferred revenue	52,501	42,183
Total current liabilities	71,197	67,412
Deferred revenue, non-current	13,527	13,322
Deferred tax liability, non-current	146	150
Other liabilities, non-current	1,566	1,667
TOTAL LIABILITIES	86,436	82,551
Commitments and Contingencies (Note 5)
STOCKHOLDERS’ EQUITY
Preferred stock—$0.0001 par value; 20,000 shares authorized, no shares issued or outstanding as of March 28, 2015 and December 27, 2014	0	0
Common stock—$0.0001 par value; 1,000,000 shares authorized, 33,171 and 32,642 shares issued and outstanding as of March 28, 2015 and December 27, 2014, respectively	3	3
Treasury stock— 8,110 shares outstanding as of March 28, 2015 and December 27, 2014	-12,469	-12,469
Additional paid-in capital	187,558	177,714
Accumulated other comprehensive income (loss)	15	-94
Accumulated deficit	-50,414	-49,719
TOTAL STOCKHOLDERS’ EQUITY	124,693	115,435
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$211,129	$197,986

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 28, 2015	Dec. 27, 2014
Statement of Financial Position [Abstract]
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	33,170,852	32,641,500
Common stock, shares outstanding	33,170,852	32,641,500
Treasury stock, shares authorized and outstanding	8,109,848	8,109,848

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
Revenue:
Product	$32,152	$20,080
Service	14,701	11,680
Total revenue	46,853	31,760
Cost of revenue:
Product	9,445	7,005
Service	1,777	1,580
Total cost of revenue	11,222	8,585
Gross profit	35,631	23,175
Operating expenses:
Research and development	11,496	10,938
Sales and marketing	18,832	18,170
General and administrative	6,019	6,005
Total operating expenses	36,347	35,113
Loss from operations	-716	-11,938
Interest income	119	61
Other expense, net	-10	-41
Loss before income tax (provision) benefit	-607	-11,918
Income tax (provision) benefit	-88	3,700
Net loss	($695)	($8,218)
Net loss per share:
Basic (in dollars per share)	($0.02)	($0.26)
Diluted (in dollars per share)	($0.02)	($0.26)
Weighted average shares used in computing net loss per share:
Basic (in shares)	32,994	31,734
Diluted (in shares)	32,994	31,734

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Loss (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
Statement of Comprehensive Income [Abstract]
Net loss	($695)	($8,218)
Other comprehensive gain (loss):
Change in unrealized gain (loss) on available-for-sale investments	109	-8
Comprehensive loss	($586)	($8,226)

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	($695)	($8,218)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	1,515	983
Stock-based compensation expense	7,343	7,858
Deferred income taxes	13	-3,719
Inventory write-down	493	1,810
Changes in operating assets and liabilities:
Accounts receivable	3,282	8,206
Inventories	1,155	-247
Prepaid expenses and other assets	-1,463	-783
Accounts payable	-1,147	47
Accrued liabilities and other liabilities	-5,247	-6,179
Deferred revenue	10,523	2,042
Net cash provided by operating activities	15,772	1,800
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of short-term investments	0	-34,430
Proceeds from sales of short-term investments	0	1,000
Proceeds from maturities of short-term investments	21,653	5,075
Purchase of property and equipment	-1,037	-2,269
Net cash provided by (used in) investing activities	20,616	-30,624
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from employee stock purchase plan	2,607	3,863
Proceeds from exercise of stock options	1,245	2,881
Costs paid for initial public offering, net	0	-8
Shares repurchased for tax withholdings on vesting of restricted stock units	-1,262	-1,632
Distribution of income to Gigamon LLC members	0	-476
Net cash provided by financing activities	2,590	4,628
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	38,978	-24,196
CASH AND CASH EQUIVALENTS — Beginning of period	38,941	79,908
CASH AND CASH EQUIVALENTS — End of period	77,919	55,712
Capital Expenditures Incurred but Not yet Paid	$156	$690

Description_of_the_Company

Description of the Company	3 Months Ended
	Mar. 28, 2015
Accounting Policies [Abstract]
Description of the Company	Description of the Company
	The Company
	Gigamon Inc. (the “Company”) designs, develops and sells products and services that together provide customers with visibility and control of network traffic. The Company serves global enterprises and service providers that seek to maintain and improve the reliability, performance and security of their network infrastructure.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 28, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies
	Basis of Presentation and Consolidation
	The Company prepared its condensed consolidated financial statements in accordance with U.S. generally accepted accounting principles (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (the “SEC”) regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. As such, the information included in this Quarterly Report on Form 10-Q should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 27, 2014.
	There have been no changes to the Company’s significant accounting policies described in the Annual Report on Form 10-K that have had a material impact on the Company’s condensed consolidated financial statements and related notes.
	The Company has a 52- or 53-week fiscal year that ends on the last Saturday in December. Fiscal 2015 is a 52-week fiscal year ending on December 26, 2015 and each quarter therein is a 13-week quarter.
	Unaudited Interim Financial Statements
	The accompanying condensed consolidated financial statements are unaudited. The unaudited interim condensed consolidated financial statements have been prepared on a basis consistent with the annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include normal recurring adjustments, necessary to fairly state the Company’s financial position as of March 28, 2015, its results of operations, comprehensive loss, and cash flows for the three months ended March 28, 2015 and March 29, 2014. The financial data and the other financial information disclosed in the accompanying notes to the condensed consolidated financial statements related to these three month periods are also unaudited. The fiscal year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. The results of operations in the three months ended March 28, 2015 are not necessarily indicative of the results to be expected for the full fiscal year or any other future periods.
	Principles of Consolidation
	The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation.
	Use of Estimates
	The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make certain 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 revenues and expenses during the reported periods. On an ongoing basis, the Company evaluates its estimates, including but not limited to those related to revenue recognition, provision for doubtful accounts, warranty reserve, excess and obsolete inventory write-downs, stock-based compensation expense, depreciable useful lives and income taxes. The Company bases its estimates on historical experience, projections for future performance and other assumptions that it believes to be reasonable under the circumstances. Actual results could differ materially from those estimates.
	Cash Equivalents and Marketable Securities
	All highly liquid marketable securities with original or remaining maturities of less than three months at the date of purchase are considered to be cash equivalents. Marketable securities are generally classified as available-for-sale for use in current operations, if required, and are reported at fair value, with unrealized gains and losses, net of tax, presented as a separate component of stockholders’ equity within accumulated other comprehensive income (loss). All realized gains and losses and unrealized losses resulting from declines in fair value that are other-than-temporary are recorded in other expense, net, in the period of occurrence. The Company uses the specific identification method to determine the realized gains and losses on investments. For all investments in marketable securities, the Company assesses whether the impairment is other-than-temporary. If the fair value of a security is less than its amortized cost basis, an impairment is considered other-than-temporary if (i) the Company has the intent to sell the security or it is more likely than not that the Company will be required to sell the security before recovery of its entire amortized cost basis, or (ii) the Company does not expect to recover the entire amortized cost of the security. If an impairment is considered other-than-temporary based on condition (i), the entire difference between the amortized cost and the fair value of the security is recognized in earnings. If an impairment is considered other-than-temporary based on condition (ii), the amount representing credit losses, defined as the difference between the present value of the cash flows expected to be collected and the amortized cost basis of the security, will be recognized in earnings, and the amount relating to all other factors will be recognized in accumulated other comprehensive income (loss). The Company evaluates both qualitative and quantitative factors such as duration and severity of the unrealized losses, credit ratings, default and loss rates of the underlying collateral, structure and credit enhancements to determine if a credit loss may exist.
	Concentrations
	The Company operates in highly competitive and rapidly changing markets that could negatively impact the Company’s operating results. A number of components that meet the Company’s manufacturing requirements are available only from single source suppliers. In addition, the Company relies on one contract manufacturer to manufacture substantially all of its products. The inability of its single source suppliers and contract manufacturer to provide the Company with adequate supplies of high-quality components and products could cause a delay in order fulfillment, which could adversely affect the Company’s revenue, cost of revenue and operating results.
	Financial instruments that potentially subject the Company to significant concentrations of credit risk consist principally of cash, cash equivalents, short-term investments and accounts receivable. The majority of the Company's cash, cash equivalents and short-term investments are held in or managed by a limited number of major financial institutions in the United States that management believes are creditworthy. Such deposits may exceed the insured limits provided on them. The Company mitigates credit risk associated with its accounts receivable by performing ongoing credit evaluations of its customers and determines if it needs to establish an allowance for doubtful accounts for estimated losses based on management’s assessment of the collectability of customer accounts. No end-user customer accounted for 10% or     more of total accounts receivable.
	The Company sells its products primarily through channel partners, including distributors and resellers, and directly to end-user customers. For the three months ended March 28, 2015 and March 29, 2014, no end-user customer accounted for 10% or more of revenue.
	Customers that represented more than 10% of total revenue and accounts receivable are the following:
		Three Months Ended
		28-Mar-15		29-Mar-14
	Percent of Revenue:
	Customer A (distributor)	38	%	48	%
	Customer B (distributor)	21	%	13	%
		As of
		28-Mar-15		27-Dec-14
	Percent of Accounts Receivable:
	Customer A (distributor)	41	%	*
	Customer B (distributor)	10	%	36	%
	* represents less than 10% of total accounts receivable
	Inventories
	Inventory is valued at the lower of cost computed on a first-in, first-out basis, or market value. The Company writes down inventory in excess of forecasted demand over a certain period, as a component of cost of revenue. In these cases, inventory is reduced to estimated realizable value based on historical usage and expected demand. At the point of inventory write-down, a new lower-cost basis for that inventory is established and subsequent changes in facts and circumstances do not result in the restoration or increase in that newly established cost basis.
	Inherent in the Company’s estimates of market value in determining inventory valuation are estimates related to economic trends, future demand for the Company’s products, and technical obsolescence of products. The Company uses a contract manufacturer to provide manufacturing services for its products. During the normal course of business, in order to manage manufacturing lead times and help ensure adequate component supply, the Company enters into agreements with the contract manufacturer that either allow them to procure inventory based upon criteria as defined by the Company, or establish the parameters defining the Company’s requirements. A portion of the Company’s reported purchase commitments arising from these agreements consists of non-cancelable commitments. The Company records a liability for firm, non-cancelable and unconditional purchase commitments for quantities in excess of its future demand forecasts consistent with the valuation of the Company’s excess and obsolete inventory.
	In the three months ended March 28, 2015 and March 29, 2014, the Company recorded $0.5 million and $1.8 million, respectively of inventory write-downs within cost of revenue.
	Revenue Recognition
	The Company generates product revenue from sales of traffic visibility solutions to customers as well as service revenue from sales of maintenance and support contracts and other billable services. Most of the Company’s products are hardware appliances containing software components that function together to deliver the essential functionality of the solution. The Company typically delivers products and services in a single transaction. The deliverables consist of traffic visibility solutions, maintenance and support, and other billable services. The Company’s typical arrangement includes the sale of one or multiple products that include first year maintenance and support as well as standard warranty. Other arrangements consist of the sale of products bundled with additional maintenance and support or a renewal of maintenance and support contracts. Billable services are billed in advance or when service is provided and performed as requested by customers. Under maintenance and support contracts, services are provided as needed by customers over the fixed arrangement term. The Company does not grant its customers a general right of return or any refund terms, except to two of the Company’s distributors which have a general right of return and in that case, revenue is deferred until sell-through has occurred. Revenue from distributors is reported net of rebates, discounts and any other sales incentives.
	The Company recognizes revenue when (1) persuasive evidence of an arrangement exists, (2) delivery has occurred or services have been rendered, (3) the sales price is fixed or determinable and (4) collectability is reasonably assured.
	When sales arrangements contain multiple elements and software and non-software components that function together to deliver the products’ essential functionality, the Company allocates revenue to each element based on a selling price hierarchy: vendor-specific objective evidence (“VSOE”) if available, third-party evidence (“TPE”) of the selling price if VSOE is not available, or best estimated selling prices (“BESP”) if neither VSOE nor TPE is available.
	When the Company enters into arrangements to provide more than one product or service (“multiple deliverables”), these arrangements are evaluated to determine if the multiple elements consist of more than one unit of accounting and can be separated accordingly. Based on separation criteria under the guidance, deliverables in multiple element arrangements can be segregated into separate units of accounting if they have value to the customer on a standalone basis. If deliverables can be separated into individual units of accounting, then the arrangement consideration is allocated among deliverables based on their relative selling price. Revenue from each deliverable is recognized when all requirements are met for that specific deliverable. If deliverables cannot be separated into separate units of accounting, then the arrangement will be accounted for as a single unit of accounting and revenue will be recognized when all requirements are met for all deliverables within the arrangement. The Company has established VSOE for maintenance and support contracts since the majority of selling prices fall within a narrow range when sold separately. TPE is not used since this information is not widely available in the market and the Company does not consider its products to be similar to or interchangeable with its competitors’ products in standalone sales to similarly situated customers. For deliverables with no established VSOE, such as standard product offerings, the Company determines the standalone selling price for such deliverables by establishing BESP, which incorporates historical selling prices, the effect of market conditions, gross margin objectives and pricing practices, as well as entity specific factors. The Company monitors and evaluates BESP on a regular basis to ensure that changes in circumstances are accounted for in a timely manner.
	Service revenue is recognized ratably over the contractual support period, which is typically one year and can be up to five years.
	In accordance with contractual provisions, the Company may offer cooperative marketing funds based on a fixed dollar percentage of product sales to certain of its channel partners or to fund specific marketing activities for these partners. The Company records such amounts as a reduction to revenue or, if the Company has evidence of fair value of the separable and identifiable benefit received, as a marketing expense.
	Revenue is recorded net of sales taxes. Costs of products not yet recognized as revenue are deferred and included as a component of prepaid expenses and other current assets in the consolidated balance sheets. As of March 28, 2015 and December 27, 2014, deferred cost of product revenue was $1.9 million and $0.8 million, respectively.
	Shipping and Handling Charges
	Shipping and handling costs are recorded in cost of revenue in the period products are shipped to customers.
	Warranty
	The Company provides five-year warranties on its hardware products against defects in manufacturing. The Company accrues for potential liability claims as a component of cost of product revenue based on historical trends of product failure rates and the expected material and labor costs to provide warranty services. The accrued warranty balance is reviewed periodically for adequacy and is included in accrued liabilities and in other non-current liabilities on the consolidated balance sheets.
	Stock-Based Compensation
	Stock-based compensation expense related to stock-based transactions, including employee and director awards, as well as employee stock purchase plan purchase rights (“ESPP purchase rights”), is measured and recognized in the consolidated financial statements based on the fair value of the award on the grant date. Stock-based compensation expense related to equity awards that can be settled in cash is measured based on the fair value on each balance sheet date until the settlement dates. The fair value of option awards and ESPP purchase rights is estimated using the Black-Scholes option-pricing model. This model requires assumptions including the market value of the Company’s common stock, expected volatility, expected term of the award, expected dividend yield and risk-free interest rate. Expected term for stock option awards is determined based on the mid-point of the vest period and the contractual period of each option award due to the Company’s limited historical stock option exercise data. Expected volatility is established based on the historical volatility of the common stock of a peer group of publicly traded companies. The stock-based compensation expense, net of estimated forfeitures, is recognized on a graded-vesting basis over the requisite service periods of the awards, unless a performance-based condition exists. Expenses for performance-based awards are recognized when the issuance of the underlying awards are probable. Expenses for consultant awards are measured based on the fair value on the vest date. Expenses related to the option grants to consultants that have not been vested as of the reporting date are marked to market until the earlier of the commitment or the completion of the underlying performance. The Company estimates a forfeiture rate to calculate the stock-based compensation for its awards based on an analysis of its historical experience, analysis of employee turnover and other related factors. The Company is currently using two separate forfeiture rates, based on the classification of the employees.
	Advertising Costs
	Expenses related to advertising of products are charged to sales and marketing expense as incurred. For all periods presented, advertising expenses were not material.
	Income Taxes
	The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in our financial statements or tax returns. In addition, deferred tax assets are recorded for the future benefit of utilizing net operating losses and research and development credit carryforwards. Valuation allowances are provided when necessary to reduce deferred tax assets to the amount expected to be realized on a more likely than not basis.
	Significant judgment is required in determining any valuation allowance recorded against deferred tax assets. In assessing the need for a valuation allowance, the Company considers all available evidence, including past operating results, estimates of future taxable income and the feasibility of any viable tax planning strategies. In the event that the Company changes its determination as to the amount of deferred tax assets that can be realized, the Company will adjust its valuation allowance with a corresponding impact to the provision for income taxes in the period in which such determination is made.
	Comprehensive Loss
	Comprehensive loss is defined as a change in equity of a business enterprise during a period, resulting from transactions from non-owner sources. Comprehensive loss is comprised of all components of net loss and the changes in the components of accumulated other comprehensive income (loss) within stockholders’ equity. The Company’s accumulated other comprehensive income (loss) includes unrealized gains and losses from its available-for-sale securities that are not considered other-than-temporarily impaired, net of taxes.
	Recent Accounting Pronouncements
	In May 2014, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers (Topic 606), which supersedes the revenue recognition requirements in Accounting Standards Codification 605, Revenue Recognition. This ASU is based on the principle that revenue is recognized to depict the transfer of 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 ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. The effective date of this ASU will be the first quarter of fiscal year 2018 using one of two retrospective application methods. The Company is currently evaluating the potential impact, if any, of this accounting standard update on its future consolidated financial statements.
	In June 2014, the FASB issued ASU No. 2014-12, Compensation-Stock Compensation (Topic 718): Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period. This ASU requires that a performance target that affects vesting and that could be achieved after the requisite service 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 attributable to the periods for which the requisite service has already been rendered. The amendments in this update are effective for annual periods and interim periods within annual periods beginning after December 15, 2015 and early adoption is permitted. The adoption of this guidance is not currently expected to have a material impact on the Company’s consolidated financial statements.
	In August 2014, the FASB issued ASU No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern, to provide guidance on management’s responsibility in evaluating whether there is a substantial doubt about a company’s ability to continue as a going concern and to provide related footnote disclosures. The effective date of this ASU will be for annual periods ending after December 15, 2016 with early adoption permitted. The adoption of this guidance is not currently expected to have a material impact on the Company’s consolidated financial statements.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 28, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements
	The Company records its financial assets and liabilities at fair value. The inputs used in the valuation methodologies in measuring fair value are defined in the fair value hierarchy as follows:
	Level 1 – Quoted prices in active markets for identical assets or liabilities.
	Level 2 – Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices 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 assets or liabilities.
	Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.
	The Company recognizes transfers among Level 1, Level 2 and Level 3 classifications as of the actual date of the events or change in circumstances that caused the transfers.
	The categorization of a financial instrument within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The carrying value of the Company’s accounts receivable, accounts payable and accrued liabilities approximates their fair value due to the short-term nature of these instruments.
	Cash, Cash Equivalents and Short-Term Investments
	The Company measures its financial instruments at fair value on a recurring basis. The components of the Company's cash, cash equivalents and short-term investments are as follows (in thousands):
				Fair Value Measured Using
		28-Mar-15		Quoted Prices		Significant			Significant
				in Active		Other			Unobservable
				Markets for		Observable			Inputs
				Identical		Inputs			(Level 3)
				Assets		(Level 2)
				(Level 1)
	Cash and cash equivalents:
	Money market funds	$	34,428	$	34,428	$	—		$	—
	Total cash equivalents	34,428		34,428		—			—
	Cash	43,491
	Total cash and cash equivalents	$	77,919
	Short-term investments:
	Corporate debt securities	$	40,917	$	—	$	40,917		$	—
	U.S. agency debt securities	27,750		—		27,750			—
	U.S. government securities	20,007		—		20,007			—
	Total short-term investments	$	88,674	$	—	$	88,674		$	—
				Fair Value Measured Using
		27-Dec-14		Quoted Prices		Significant			Significant
				in Active		Other			Unobservable
				Markets for		Observable			Inputs
				Identical		Inputs			(Level 3)
				Assets		(Level 2)
				(Level 1)
	Cash and cash equivalents:
	Money market funds	$	15,976	$	15,976	$	—		$	—
	Total cash equivalents	15,976		15,976		—			—
	Cash	22,965
	Total cash and cash equivalents	$	38,941
	Short-term investments:
	Corporate debt securities	$	58,707	$	—	$	58,707		$	—
	U.S. agency debt securities	31,779		—		31,779			—
	U.S. government securities	19,979		—		19,979			—
	Total short-term investments	$	110,465	$	—	$	110,465		$	—
	The Company considers all highly liquid investments with maturity of three months or less at the time of purchase to be cash equivalents. The Company holds money market funds that invest primarily in high-quality short-term money-market instruments, and these funds are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Company presents available-for-sale investments as current assets as they are available for the Company's current operations.
	Money market funds have been classified as Level 1 because these securities are valued based upon quoted prices in active markets. The Company’s Level 2 assets are priced using quoted market prices for similar instruments or non-binding market prices that are corroborated by observable market data. Observable inputs reflect market data obtained from independent sources. The Company’s policy is to recognize transfers among Level 1, Level 2 and Level 3 classifications as of the actual date of the events or change in circumstances that caused the transfers. The Company did not have any transfers between Level 1 and Level 2 in the three months ended March 28, 2015.
	As of March 28, 2015 and December 27, 2014, the Company had no liabilities measured at fair value.
	Financial instruments measured at amortized costs, gross unrealized gains, gross unrealized losses and fair value by significant investment categories are summarized as follows (in thousands):
		As of March 28, 2015
		Amortized		Gross		Gross			Fair Value
		Costs		Unrealized		Unrealized
				Gains		Losses
	Cash and cash equivalents:
	Money market funds	$	34,428	$	—	$	—		$	34,428
	Cash	43,491		—		—			43,491
	Total cash and cash equivalents	$	77,919	$	—	$	—		$	77,919
	Short-term investments:
	Corporate debt securities	$	40,931	$	10	$	(24	)	$	40,917
	U.S. agency debt securities	27,742		10		(2		)	27,750
	U.S. government securities	19,986		21		—			20,007
	Total short-term investments	$	88,659	$	41	$	(26	)	$	88,674
		27-Dec-14
		Amortized		Gross		Gross			Fair Value
		Costs		Unrealized		Unrealized
				Gains		Losses
Cash and cash equivalents:
Money market funds	$	15,976	$	—	$	—		$	15,976
Cash	22,965		—		—			22,965
Total cash and cash equivalents	$	38,941	$	—	$	—		$	38,941
Short-term investments:
Corporate debt securities	$	58,777	$	4	$	(74	)	$	58,707
U.S. agency debt securities	31,800		1		(22		)	31,779
U.S. government securities	19,982		7		(10		)	19,979
Total short-term investments	$	110,559	$	12	$	(106	)	$	110,465
The Company’s realized gain was immaterial in the three months ended March 28, 2015. There were no securities in a continuous loss position for 12 months or longer as of March 28, 2015 and December 27, 2014.
The following table summarizes the estimated fair value of the Company’s debt investments, designated as available-for-sale classified by the contractual maturity date of the security:
	As of
	28-Mar-15		27-Dec-14
Due within one year	$	99,042	$	90,555
Due between one and five years	24,060		35,886
Total cash equivalents and short-term investments	$	123,102	$	126,441

Balance_Sheet_Components

Balance Sheet Components	3 Months Ended
	Mar. 28, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Components	Balance Sheet Components
	Inventories
	Inventories are comprised of the following (in thousands):
		As of
		28-Mar-15			27-Dec-14
	Raw materials	$	319		$	433
	Finished goods	4,307			6,118
	Total inventories	$	4,626		$	6,551
	Accrued Liabilities
	Accrued liabilities are comprised of the following (in thousands):
		As of
		28-Mar-15			27-Dec-14
	Accrued employee related costs	$	10,701		$	16,021
	Accrued inventory and other purchases	1,625			1,830
	Accrued professional services	661			761
	Other accruals	4,464			4,226
	Total accrued liabilities	$	17,451		$	22,838
	Accrued Warranty
	Accrued Warranty is comprised of (in thousands):
		Three Months Ended
		28-Mar-15			29-Mar-14
	Accrued warranty balance at beginning of period	$	875		$	686
	Accrual for warranty during the period	275			187
	Actual costs incurred	(219		)	(195		)
	Accrued warranty balance at end of period	$	931		$	678
	Deferred Revenue
	Deferred revenue is comprised of the following (in thousands):
		As of
		28-Mar-15			27-Dec-14
	Deferred service revenue	$	52,177		$	51,699
	Deferred product revenue	13,851			3,806
	Total deferred revenue	$	66,028		$	55,505
	Accumulated Other Comprehensive Income (Loss)
	Accumulated other comprehensive income (loss) consists of unrealized gains and losses from available-for-sale securities. The following summarizes the activity within accumulated other comprehensive income (loss) (in thousands):
		Accumulated Other Comprehensive Income (Loss)
		Net Unrealized Gains (Losses)			Income Tax			Net Unrealized Gains (Losses),
					Provision			net of tax
	Balance as of December 27, 2014	$	(94	)	$	—		$	(94	)
	Available-for-sale securities:
	Unrealized gains, net	109			—			109
	Total other comprehensive income	109			—			109
	Balance as of March 28, 2015	$	15		$	—		$	15
	There were no reclassifications out of accumulated other comprehensive income into the consolidated statements of operations in the three months ended March 28, 2015 and March 29, 2014.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 28, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Lease Commitments
	The Company leases office space for its current headquarters in Santa Clara, California and its United Kingdom subsidiary under non-cancelable operating leases that expire at various times through fiscal 2019. The Company has also entered into lease agreements for additional office space in New York, Virginia, Australia, China, Japan, Hong Kong, India, Russia, Singapore, the United Arab Emirates, and the United Kingdom. The Company recognizes rent expense on a straight-line basis over the lease period.
	Rent expense related to the Company’s operating leases was $0.8 million for the three months ended March 28, 2015 and March 29, 2014, respectively.
	Future minimum lease payments under non-cancelable operating leases as of March 28, 2015 were as follows (in thousands):
	Fiscal Year:
	2015 (remaining nine months)	$	2,574
	2016	3,283
	2017	3,330
	2018	957
	2019	82
	Total	$	10,226
	Purchase Commitments
	As of March 28, 2015 and December 27, 2014, the Company’s purchase orders for inventories and related components totaled $5.6 million and $3.6 million, respectively.
	Legal Proceedings
	From time to time, the Company may become involved in legal proceedings arising in the ordinary course of business. The Company is not currently a party to any legal proceedings the outcome of which, if determined adversely to the Company, would individually or in the aggregate be expected to have a material adverse effect on its business, operating results, financial condition or cash flows.
	Indemnification Obligations
	Under the indemnification provisions of its standard sales related contracts, the Company agrees to defend its customers against third-party claims asserting infringement of certain intellectual property rights, which may include patents, copyrights, trademarks, or trade secrets, and to pay judgments entered on such claims. The Company’s exposure under these indemnification provisions is generally limited to the total amount paid by its customer under the agreement. However, certain agreements include indemnification provisions that could potentially expose the Company to losses in excess of the amount received under the agreement. The Company has not incurred any costs as a result of such indemnifications and has not accrued any liabilities related to such obligations in its consolidated financial statements. In addition, the Company indemnifies its officers, directors and certain key employees while they are serving in good faith in the company capacities. To date, there have been no claims under any indemnification provisions.

Preferred_Stock_and_Stockholde

Preferred Stock and Stockholders' Equity	3 Months Ended
	Mar. 28, 2015
Equity [Abstract]
Preferred Stock and Stockholders' Equity	Preferred Stock and Stockholders’ Equity
	Preferred Stock
	The Company has authorized 20,000,000 shares of undesignated preferred stock, $0.0001 par value per share. As of March 28, 2015 and December 27, 2014, the Company had no shares of preferred stock issued or outstanding.
	Common Stock
	The Company has authorized 1,000,000,000 shares of common stock, $0.0001 par value per share. Each holder of common stock is entitled to one vote for each share of common stock held. Cumulative voting for the election of directors is not provided in the Company’s amended and restated certificate of incorporation. The Company’s common stock is not entitled to preemptive rights, and is not subject to conversion, redemption or sinking fund provisions. Subject to preferences that may apply to any shares of preferred stock outstanding at the time, the holders of common stock are entitled to receive dividends out of funds legally available if the Company's board of directors (the "Board"), in its discretion, determines to issue dividends and then only at the times and in the amounts that the Board may determine.
	As of March 28, 2015 and December 27, 2014, the Company had 33,170,852 and 32,641,500 shares of common stock issued and outstanding, respectively.
	Treasury Stock
	As of March 28, 2015 and December 27, 2014, the Company had 8,109,848 shares of treasury stock outstanding, with a carrying value of $12.5 million, or $1.53 per share, within stockholders’ equity on its condensed consolidated balance sheet. The treasury stock was purchased in fiscal 2010 pursuant to a purchase and redemption agreement.
	Equity Award Plans
	2013 Equity Incentive Plan
	In May 2013, the Company adopted the 2013 Equity Incentive Plan (the “2013 Equity Plan”). All authorized but unissued shares of the Company’s 2012 Unit Option Plan (the "2012 Plan") were added to the 2013 Equity Plan’s authorized pool in June 2013. The Company is authorized to issue up to a maximum of 2,929,481 shares of common stock for future issuance, plus up to an additional 4,967,172 shares upon termination of awards under the 2012 Plan. In addition, the 2013 Equity Plan is subject to increase annually on the first day of each of the Company’s fiscal years beginning with fiscal 2014, by an amount equal to the least of (i) 1,464,740 shares, (ii) 5% of the outstanding shares of common stock as of the last day of the immediately preceding fiscal year, or (iii) such other amount as determined by the Board. In the twelve months ended December 27, 2014, an additional 1,464,740 shares of common stock were authorized for future issuance under the 2013 Equity Incentive Plan and an additional 1,464,740 shares were authorized during the three months ended March 28, 2015. Vested but unexercised options, under the 2013 Equity Plan, expire three months after termination of service with the Company. As of March 28, 2015, outstanding awards under the 2013 Equity Plan and the 2012 Plan covered 3,320,873 shares and 1,570,411 shares of the Company's common stock, respectively.
	The 2013 Equity Plan permits the grant of stock options, stock appreciation rights, restricted stock, restricted stock units ("RSUs"), performance units and performance shares to employees, directors and consultants of the Company.
	Employee Stock Purchase Plan
	In conjunction with the completion of its initial public offering (the "IPO") in June 2013, the Company adopted the 2013 Employee Stock Purchase Plan (the “ESPP”). A maximum of 439,422 shares were initially authorized for future issuance and the number of authorized shares under the ESPP is subject to an increase on an annual basis. In the twelve months ended December 27, 2014, an additional 439,422 shares of common stock were authorized for future issuance under the ESPP and an additional 439,422 shares were authorized during the three months ended March 28, 2015. Eligible employees can purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to plan limitations. Employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock (i) at the date of commencement of the offering period or (ii) at the last day of the purchase period. The ESPP provides for a 24-month offering period comprised of four purchase periods of approximately six months. The offering periods are scheduled to start on the first trading day on or after February 15 and August 15 of each year, except for the first offering period, which commenced on the first trading day upon the completion of the Company’s IPO, or June 12, 2013, and ends on August 17, 2015. In the three months ended March 28, 2015 and March 29, 2014, the Company recorded stock-based compensation expense of $0.7 million and $1.7 million, respectively for its ESPP. For the three months ended March 28, 2015 there was one purchase period that resulted in the issuance of 273,301 shares of common stock at a weighted average purchase price of $9.54 per share.
	Stock Option
	Stock options granted under the 2013 Equity Plan and formerly under the 2012 Plan (together, the “Option Plans”), are generally subject to a four-year vesting period whereby stock options become 25% vested on the first anniversary of the grant date and then ratably monthly thereafter through the end of the vesting period. Vested stock options may be exercised up to ten years from the vesting commencement date, with certain options granted in fiscal 2015 expiring seven years from the date of grant. Under the 2012 Plan, vested but unexercised stock options expire 30 days after termination of service with the Company. Under the 2013 Equity Plan, vested but unexercised stock options expire three months after termination of service with the Company.
	The following table summarizes the stock option activity under the Company’s Option Plans:
		Number of		Weighted-			Weighted-	Aggregate
		Stock		Average			Average	Intrinsic
		Options		Exercise			Remaining	Value
		Outstanding		Price			Contractual
							Life (Years)
		(in thousands)
	Balance — December 27, 2014	2,386,412		$	12.91		8.21	$	14,403
	Options granted	408,000		$	21.44
	Options exercised	(172,709	)	$	7.2
	Options canceled	(58,895	)	$	10.38
	Balance — March 28, 2015	2,562,808		$	14.71		7.82	$	18,809
	Vested and expected to vest — March 28, 2015	2,365,419		$	14.41		7.81	$	18,010
	Exercisable — March 28, 2015	957,721		$	11.48		7.67	$	9,884
	Aggregate intrinsic value represents the difference between the exercise price of the awards and the Company’s fair value per share of $21.10 and $17.47 as of March 28, 2015 and December 27, 2014, respectively, for the total number of underlying options. Weighted-average fair value per share for option awards vested in the three months ended March 28, 2015 and March 29, 2014 was $10.76 and $11.48, respectively. As of March 28, 2015 and December 27, 2014, there were 34,151 and 36,495 shares of common stock subject to stock options with performance-based vesting criteria, respectively.
	Restricted Stock Unit Activity
	RSUs generally vest over a period of one to four years. RSU vesting dates are determined by the Company. The vesting is subject to the employee’s continuing service with the Company over that period. Until vested, RSUs do not have the voting or dividend participation rights of the Company’s common stock and the shares of the Company’s common stock underlying the awards are not considered issued and outstanding. The cost of RSUs is determined using the fair value of the Company’s common stock on the date of the grant.
	The following table summarizes the RSU activity under the Company’s Option Plans:
		Number of		Weighted-			Weighted-	Aggregate
		RSUs		Average			Average	Intrinsic
		Outstanding		Grant Date			Remaining	Value
				Fair Value			Contractual
							Life (Years)
								(in thousands)
	Balance - December 27, 2014	1,731,225		$	18.79		1.27	$	30,245
	RSUs granted	861,107		$	21.3
	RSUs vested	(142,196	)	$	19.36
	RSUs canceled	(121,660	)	$	22.87
	Balance - March 28, 2015	2,328,476		$	19.47		1.46	$	49,131
	Vested and expected to vest — March 28, 2015	2,009,813		$	19.3		1.34	$	42,407
	Aggregate intrinsic value for RSUs represents the Company’s fair market value per share of $21.10 and $17.47, as of March 28, 2015 and December 27, 2014, respectively, for the total number of underlying RSUs.
	Stock-Based Compensation Expense
	The fair value of stock options and ESPP purchase rights is estimated on the date of grant using the Black-Scholes option-pricing model. The fair values of the option awards and ESPP purchase rights granted and the assumptions used in the Black-Scholes option pricing model are summarized as follows:
		Three Months Ended
		March 28,	March 29,
		2015	2014
	Stock option awards:
	Expected term (in years)	4.6	6.0-6.1
	Risk-free interest rate	1.60%	1.8%-1.9%
	Expected volatility	56.04%	61.90%
	Expected dividend rate	—%	—%
	Grant date fair value per award	$10.11	$17.32 - $17.67
	ESPP purchase right:
	Expected term (in years)	0.50 - 2.0	0.50 - 2.0
	Risk-free interest rate	0.07% - 0.70%	0.1% - 0.3%
	Expected volatility	37.6% - 50.3%	44.8% - 52.7%
	Expected dividend rate	—%	—%
	Grant date fair value per share	$5.48 - $9.18	$8.23 - $13.06
The following table summarizes the stock-based compensation expense recorded in the Company’s condensed consolidated statement of operations (in thousands):
	Three Months Ended
	March 28,			March 29,
	2015			2014
Cost of revenue	$	549		$	448
Research and development	2,096			2,599
Sales and marketing	2,448			2,773
General and administrative	2,250			2,038
Total stock-based compensation expense	$	7,343		$	7,858
As of March 28, 2015, unrecognized compensation expense related to stock options, RSUs and ESPP purchase rights, net of estimated forfeitures, was $7.0 million, $24.2 million and $2.5 million, respectively.

Defined_Contribution_Plans

Defined Contribution Plans	3 Months Ended
	Mar. 28, 2015
Postemployment Benefits [Abstract]
Defined Contribution Plans	Defined Contribution Plans
	The Company’s contributions to the 401(k) defined contribution plan, which are expensed immediately as compensation costs, were $0.4 million, $0.7 million for three months ended March 28, 2015 and March 29, 2014, respectively.

Income_Tax

Income Tax	3 Months Ended
	Mar. 28, 2015
Income Tax Disclosure [Abstract]
Income Tax	Income Tax
	The Company recorded an income tax expense of $0.1 million and an income tax benefit of $3.7 million for the three months ended March 28, 2015 and March 29, 2014, respectively. The tax provision of $0.1 million as of March 28, 2015 represents foreign income tax expense. The tax provision recorded does not reflect any projected change in net deferred taxes, as the Company cannot conclude that it is more likely than not that it will be able to utilize its deferred tax assets in the foreseeable future.
	The Company files annual income tax returns in multiple tax jurisdictions on a worldwide basis. A number of years may lapse before an uncertain tax position is audited and finally resolved. While it is often difficult to predict the final outcome or the timing of resolution of any particular uncertain tax position, the Company believes that its reserves for income taxes reflect the most likely outcomes. The Company adjusts these reserves, as well as the related interest, in light of changing facts and circumstances. Settlement of any particular position could require the use of cash.
	As of March 28, 2015, changes to the Company's uncertain tax positions in the next 12 months that are reasonably possible are not expected to have a material impact on the Company's financial position or results of operations. The Company recognizes interest and penalties related to uncertain tax positions as part of the income tax provision. To date, no such interest and penalties have been accrued.

Net_Loss_per_Share

Net Loss per Share	3 Months Ended
	Mar. 28, 2015
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share
	Basic net loss per common share is computed by dividing net loss by the weighted average number of common shares outstanding.
	Due to the net loss incurred in the three months ended March 28, 2015 and March 29, 2014, potential dilutive securities were excluded from the calculation of diluted net loss per share attributable to common stockholders for such period as their effect was anti-dilutive. The following table presents the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except per share data):
		Three Months Ended
		28-Mar-15			29-Mar-14
	Numerator:
	Net loss attributable to common stockholders	$	(695	)	$	(8,218	)
	Denominator:
	Weighted average shares used for basic net loss per share computation	32,994			31,734
	Net loss per share attributable to common stockholders :
	Basic	$	(0.02	)	$	(0.26	)
	Diluted	$	(0.02	)	$	(0.26	)
	The following shares of potentially dilutive securities were excluded from the computation of diluted net loss per share for the periods presented (in thousands):
		Three Months Ended
		28-Mar-15		29-Mar-14
	Equity awards to purchase common stock	4,891		4,399

Segment_Information

Segment Information	3 Months Ended
	Mar. 28, 2015
Segment Reporting [Abstract]
Segment Information	Segment Information
	Operating segments are defined as components of an enterprise that engage in business activities for which separate discrete financial information is available and evaluated by the chief operating decision maker in deciding how to allocate resources and assessing performance. The Company’s chief operating decision maker is its chief executive officer. The chief executive officer reviews financial information presented on a consolidated basis, for purposes of allocating resources and evaluating financial performance. The Company has one business activity and there are no segment managers who are held accountable for operations, or plans for levels or components below the consolidated unit level. Accordingly, the Company operates as a single reportable segment.
	The following table summarizes the Company’s revenue by geographic region, based on the location to where the product was shipped (in thousands):
		Three Months Ended
		28-Mar-15		29-Mar-14
	United States	$	32,633	$	24,421
	Rest of Americas	3,091		1,697
	Europe, Middle East and Africa	7,482		3,704
	Asia Pacific	3,647		1,938
	Total	$	46,853	$	31,760
	The Company’s long-lived assets by geographic region are summarized as follows (in thousands):
		As of
		28-Mar-15		27-Dec-14
	United States	$	6,947	$	7,218
	Other	158		169
	Total	$	7,105	$	7,387

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 28, 2015
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies [Text Block]	Basis of Presentation and Consolidation
	The Company prepared its condensed consolidated financial statements in accordance with U.S. generally accepted accounting principles (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (the “SEC”) regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. As such, the information included in this Quarterly Report on Form 10-Q should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 27, 2014.
	There have been no changes to the Company’s significant accounting policies described in the Annual Report on Form 10-K that have had a material impact on the Company’s condensed consolidated financial statements and related notes.
	The Company has a 52- or 53-week fiscal year that ends on the last Saturday in December. Fiscal 2015 is a 52-week fiscal year ending on December 26, 2015 and each quarter therein is a 13-week quarter.
Unaudited Interim Disclosure Policy [Text Block]	Unaudited Interim Financial Statements
	The accompanying condensed consolidated financial statements are unaudited. The unaudited interim condensed consolidated financial statements have been prepared on a basis consistent with the annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include normal recurring adjustments, necessary to fairly state the Company’s financial position as of March 28, 2015, its results of operations, comprehensive loss, and cash flows for the three months ended March 28, 2015 and March 29, 2014. The financial data and the other financial information disclosed in the accompanying notes to the condensed consolidated financial statements related to these three month periods are also unaudited. The fiscal year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. The results of operations in the three months ended March 28, 2015 are not necessarily indicative of the results to be expected for the full fiscal year or any other future periods.
Basis of Presentation and Consolidation	Principles of Consolidation
	The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates
	The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make certain 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 revenues and expenses during the reported periods. On an ongoing basis, the Company evaluates its estimates, including but not limited to those related to revenue recognition, provision for doubtful accounts, warranty reserve, excess and obsolete inventory write-downs, stock-based compensation expense, depreciable useful lives and income taxes. The Company bases its estimates on historical experience, projections for future performance and other assumptions that it believes to be reasonable under the circumstances. Actual results could differ materially from those estimates.
Cash Equivalents and Marketable Securities	Cash Equivalents and Marketable Securities
	All highly liquid marketable securities with original or remaining maturities of less than three months at the date of purchase are considered to be cash equivalents. Marketable securities are generally classified as available-for-sale for use in current operations, if required, and are reported at fair value, with unrealized gains and losses, net of tax, presented as a separate component of stockholders’ equity within accumulated other comprehensive income (loss). All realized gains and losses and unrealized losses resulting from declines in fair value that are other-than-temporary are recorded in other expense, net, in the period of occurrence. The Company uses the specific identification method to determine the realized gains and losses on investments. For all investments in marketable securities, the Company assesses whether the impairment is other-than-temporary. If the fair value of a security is less than its amortized cost basis, an impairment is considered other-than-temporary if (i) the Company has the intent to sell the security or it is more likely than not that the Company will be required to sell the security before recovery of its entire amortized cost basis, or (ii) the Company does not expect to recover the entire amortized cost of the security. If an impairment is considered other-than-temporary based on condition (i), the entire difference between the amortized cost and the fair value of the security is recognized in earnings. If an impairment is considered other-than-temporary based on condition (ii), the amount representing credit losses, defined as the difference between the present value of the cash flows expected to be collected and the amortized cost basis of the security, will be recognized in earnings, and the amount relating to all other factors will be recognized in accumulated other comprehensive income (loss). The Company evaluates both qualitative and quantitative factors such as duration and severity of the unrealized losses, credit ratings, default and loss rates of the underlying collateral, structure and credit enhancements to determine if a credit loss may exist.
Concentrations	Concentrations
	The Company operates in highly competitive and rapidly changing markets that could negatively impact the Company’s operating results. A number of components that meet the Company’s manufacturing requirements are available only from single source suppliers. In addition, the Company relies on one contract manufacturer to manufacture substantially all of its products. The inability of its single source suppliers and contract manufacturer to provide the Company with adequate supplies of high-quality components and products could cause a delay in order fulfillment, which could adversely affect the Company’s revenue, cost of revenue and operating results.
	Financial instruments that potentially subject the Company to significant concentrations of credit risk consist principally of cash, cash equivalents, short-term investments and accounts receivable. The majority of the Company's cash, cash equivalents and short-term investments are held in or managed by a limited number of major financial institutions in the United States that management believes are creditworthy. Such deposits may exceed the insured limits provided on them. The Company mitigates credit risk associated with its accounts receivable by performing ongoing credit evaluations of its customers and determines if it needs to establish an allowance for doubtful accounts for estimated losses based on management’s assessment of the collectability of customer accounts. No end-user customer accounted for 10% or     more of total accounts receivable.
	The Company sells its products primarily through channel partners, including distributors and resellers, and directly to end-user customers. For the three months ended March 28, 2015 and March 29, 2014, no end-user customer accounted for 10% or more of revenue.
Inventories	Inventories
	Inventory is valued at the lower of cost computed on a first-in, first-out basis, or market value. The Company writes down inventory in excess of forecasted demand over a certain period, as a component of cost of revenue. In these cases, inventory is reduced to estimated realizable value based on historical usage and expected demand. At the point of inventory write-down, a new lower-cost basis for that inventory is established and subsequent changes in facts and circumstances do not result in the restoration or increase in that newly established cost basis.
	Inherent in the Company’s estimates of market value in determining inventory valuation are estimates related to economic trends, future demand for the Company’s products, and technical obsolescence of products. The Company uses a contract manufacturer to provide manufacturing services for its products. During the normal course of business, in order to manage manufacturing lead times and help ensure adequate component supply, the Company enters into agreements with the contract manufacturer that either allow them to procure inventory based upon criteria as defined by the Company, or establish the parameters defining the Company’s requirements. A portion of the Company’s reported purchase commitments arising from these agreements consists of non-cancelable commitments. The Company records a liability for firm, non-cancelable and unconditional purchase commitments for quantities in excess of its future demand forecasts consistent with the valuation of the Company’s excess and obsolete inventory.
Revenue Recognition	Revenue Recognition
	The Company generates product revenue from sales of traffic visibility solutions to customers as well as service revenue from sales of maintenance and support contracts and other billable services. Most of the Company’s products are hardware appliances containing software components that function together to deliver the essential functionality of the solution. The Company typically delivers products and services in a single transaction. The deliverables consist of traffic visibility solutions, maintenance and support, and other billable services. The Company’s typical arrangement includes the sale of one or multiple products that include first year maintenance and support as well as standard warranty. Other arrangements consist of the sale of products bundled with additional maintenance and support or a renewal of maintenance and support contracts. Billable services are billed in advance or when service is provided and performed as requested by customers. Under maintenance and support contracts, services are provided as needed by customers over the fixed arrangement term. The Company does not grant its customers a general right of return or any refund terms, except to two of the Company’s distributors which have a general right of return and in that case, revenue is deferred until sell-through has occurred. Revenue from distributors is reported net of rebates, discounts and any other sales incentives.
	The Company recognizes revenue when (1) persuasive evidence of an arrangement exists, (2) delivery has occurred or services have been rendered, (3) the sales price is fixed or determinable and (4) collectability is reasonably assured.
	When sales arrangements contain multiple elements and software and non-software components that function together to deliver the products’ essential functionality, the Company allocates revenue to each element based on a selling price hierarchy: vendor-specific objective evidence (“VSOE”) if available, third-party evidence (“TPE”) of the selling price if VSOE is not available, or best estimated selling prices (“BESP”) if neither VSOE nor TPE is available.
	When the Company enters into arrangements to provide more than one product or service (“multiple deliverables”), these arrangements are evaluated to determine if the multiple elements consist of more than one unit of accounting and can be separated accordingly. Based on separation criteria under the guidance, deliverables in multiple element arrangements can be segregated into separate units of accounting if they have value to the customer on a standalone basis. If deliverables can be separated into individual units of accounting, then the arrangement consideration is allocated among deliverables based on their relative selling price. Revenue from each deliverable is recognized when all requirements are met for that specific deliverable. If deliverables cannot be separated into separate units of accounting, then the arrangement will be accounted for as a single unit of accounting and revenue will be recognized when all requirements are met for all deliverables within the arrangement. The Company has established VSOE for maintenance and support contracts since the majority of selling prices fall within a narrow range when sold separately. TPE is not used since this information is not widely available in the market and the Company does not consider its products to be similar to or interchangeable with its competitors’ products in standalone sales to similarly situated customers. For deliverables with no established VSOE, such as standard product offerings, the Company determines the standalone selling price for such deliverables by establishing BESP, which incorporates historical selling prices, the effect of market conditions, gross margin objectives and pricing practices, as well as entity specific factors. The Company monitors and evaluates BESP on a regular basis to ensure that changes in circumstances are accounted for in a timely manner.
	Service revenue is recognized ratably over the contractual support period, which is typically one year and can be up to five years.
	In accordance with contractual provisions, the Company may offer cooperative marketing funds based on a fixed dollar percentage of product sales to certain of its channel partners or to fund specific marketing activities for these partners. The Company records such amounts as a reduction to revenue or, if the Company has evidence of fair value of the separable and identifiable benefit received, as a marketing expense.
	Revenue is recorded net of sales taxes. Costs of products not yet recognized as revenue are deferred and included as a component of prepaid expenses and other current assets in the consolidated balance sheets.
Shipping and Handling Charges	Shipping and Handling Charges
	Shipping and handling costs are recorded in cost of revenue in the period products are shipped to customers.
Warranty	Warranty
	The Company provides five-year warranties on its hardware products against defects in manufacturing. The Company accrues for potential liability claims as a component of cost of product revenue based on historical trends of product failure rates and the expected material and labor costs to provide warranty services. The accrued warranty balance is reviewed periodically for adequacy and is included in accrued liabilities and in other non-current liabilities on the consolidated balance sheets.
Advertising Costs	Advertising Costs
	Expenses related to advertising of products are charged to sales and marketing expense as incurred. For all periods presented, advertising expenses were not material.
Stock-Based Compensation	Stock-Based Compensation
	Stock-based compensation expense related to stock-based transactions, including employee and director awards, as well as employee stock purchase plan purchase rights (“ESPP purchase rights”), is measured and recognized in the consolidated financial statements based on the fair value of the award on the grant date. Stock-based compensation expense related to equity awards that can be settled in cash is measured based on the fair value on each balance sheet date until the settlement dates. The fair value of option awards and ESPP purchase rights is estimated using the Black-Scholes option-pricing model. This model requires assumptions including the market value of the Company’s common stock, expected volatility, expected term of the award, expected dividend yield and risk-free interest rate. Expected term for stock option awards is determined based on the mid-point of the vest period and the contractual period of each option award due to the Company’s limited historical stock option exercise data. Expected volatility is established based on the historical volatility of the common stock of a peer group of publicly traded companies. The stock-based compensation expense, net of estimated forfeitures, is recognized on a graded-vesting basis over the requisite service periods of the awards, unless a performance-based condition exists. Expenses for performance-based awards are recognized when the issuance of the underlying awards are probable. Expenses for consultant awards are measured based on the fair value on the vest date. Expenses related to the option grants to consultants that have not been vested as of the reporting date are marked to market until the earlier of the commitment or the completion of the underlying performance. The Company estimates a forfeiture rate to calculate the stock-based compensation for its awards based on an analysis of its historical experience, analysis of employee turnover and other related factors.
Income Taxes	Income Taxes
	The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in our financial statements or tax returns. In addition, deferred tax assets are recorded for the future benefit of utilizing net operating losses and research and development credit carryforwards. Valuation allowances are provided when necessary to reduce deferred tax assets to the amount expected to be realized on a more likely than not basis.
	Significant judgment is required in determining any valuation allowance recorded against deferred tax assets. In assessing the need for a valuation allowance, the Company considers all available evidence, including past operating results, estimates of future taxable income and the feasibility of any viable tax planning strategies. In the event that the Company changes its determination as to the amount of deferred tax assets that can be realized, the Company will adjust its valuation allowance with a corresponding impact to the provision for income taxes in the period in which such determination is made.
Comprehensive Loss	Comprehensive Loss
	Comprehensive loss is defined as a change in equity of a business enterprise during a period, resulting from transactions from non-owner sources. Comprehensive loss is comprised of all components of net loss and the changes in the components of accumulated other comprehensive income (loss) within stockholders’ equity. The Company’s accumulated other comprehensive income (loss) includes unrealized gains and losses from its available-for-sale securities that are not considered other-than-temporarily impaired, net of taxes.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In May 2014, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers (Topic 606), which supersedes the revenue recognition requirements in Accounting Standards Codification 605, Revenue Recognition. This ASU is based on the principle that revenue is recognized to depict the transfer of 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 ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. The effective date of this ASU will be the first quarter of fiscal year 2018 using one of two retrospective application methods. The Company is currently evaluating the potential impact, if any, of this accounting standard update on its future consolidated financial statements.
	In June 2014, the FASB issued ASU No. 2014-12, Compensation-Stock Compensation (Topic 718): Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period. This ASU requires that a performance target that affects vesting and that could be achieved after the requisite service 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 attributable to the periods for which the requisite service has already been rendered. The amendments in this update are effective for annual periods and interim periods within annual periods beginning after December 15, 2015 and early adoption is permitted. The adoption of this guidance is not currently expected to have a material impact on the Company’s consolidated financial statements.
	In August 2014, the FASB issued ASU No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern, to provide guidance on management’s responsibility in evaluating whether there is a substantial doubt about a company’s ability to continue as a going concern and to provide related footnote disclosures. The effective date of this ASU will be for annual periods ending after December 15, 2016 with early adoption permitted. The adoption of this guidance is not currently expected to have a material impact on the Company’s consolidated financial statements.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 28, 2015
Accounting Policies [Abstract]
Customers Representing Major Revenue and Accounts Receivable	Customers that represented more than 10% of total revenue and accounts receivable are the following:
		Three Months Ended
		28-Mar-15		29-Mar-14
	Percent of Revenue:
	Customer A (distributor)	38	%	48	%
	Customer B (distributor)	21	%	13	%
		As of
		28-Mar-15		27-Dec-14
	Percent of Accounts Receivable:
	Customer A (distributor)	41	%	*
	Customer B (distributor)	10	%	36	%
	* represents less than 10% of total accounts receivable

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 28, 2015
Fair Value Disclosures [Abstract]
Components of Cash and Cash Equivalents	The Company measures its financial instruments at fair value on a recurring basis. The components of the Company's cash, cash equivalents and short-term investments are as follows (in thousands):
				Fair Value Measured Using
		28-Mar-15		Quoted Prices		Significant			Significant
				in Active		Other			Unobservable
				Markets for		Observable			Inputs
				Identical		Inputs			(Level 3)
				Assets		(Level 2)
				(Level 1)
	Cash and cash equivalents:
	Money market funds	$	34,428	$	34,428	$	—		$	—
	Total cash equivalents	34,428		34,428		—			—
	Cash	43,491
	Total cash and cash equivalents	$	77,919
	Short-term investments:
	Corporate debt securities	$	40,917	$	—	$	40,917		$	—
	U.S. agency debt securities	27,750		—		27,750			—
	U.S. government securities	20,007		—		20,007			—
	Total short-term investments	$	88,674	$	—	$	88,674		$	—
				Fair Value Measured Using
		27-Dec-14		Quoted Prices		Significant			Significant
				in Active		Other			Unobservable
				Markets for		Observable			Inputs
				Identical		Inputs			(Level 3)
				Assets		(Level 2)
				(Level 1)
	Cash and cash equivalents:
	Money market funds	$	15,976	$	15,976	$	—		$	—
	Total cash equivalents	15,976		15,976		—			—
	Cash	22,965
	Total cash and cash equivalents	$	38,941
	Short-term investments:
	Corporate debt securities	$	58,707	$	—	$	58,707		$	—
	U.S. agency debt securities	31,779		—		31,779			—
	U.S. government securities	19,979		—		19,979			—
	Total short-term investments	$	110,465	$	—	$	110,465		$	—
Schedule of Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Investments	Financial instruments measured at amortized costs, gross unrealized gains, gross unrealized losses and fair value by significant investment categories are summarized as follows (in thousands):
		As of March 28, 2015
		Amortized		Gross		Gross			Fair Value
		Costs		Unrealized		Unrealized
				Gains		Losses
	Cash and cash equivalents:
	Money market funds	$	34,428	$	—	$	—		$	34,428
	Cash	43,491		—		—			43,491
	Total cash and cash equivalents	$	77,919	$	—	$	—		$	77,919
	Short-term investments:
	Corporate debt securities	$	40,931	$	10	$	(24	)	$	40,917
	U.S. agency debt securities	27,742		10		(2		)	27,750
	U.S. government securities	19,986		21		—			20,007
	Total short-term investments	$	88,659	$	41	$	(26	)	$	88,674
		27-Dec-14
		Amortized		Gross		Gross			Fair Value
		Costs		Unrealized		Unrealized
				Gains		Losses
	Cash and cash equivalents:
	Money market funds	$	15,976	$	—	$	—		$	15,976
	Cash	22,965		—		—			22,965
	Total cash and cash equivalents	$	38,941	$	—	$	—		$	38,941
	Short-term investments:
	Corporate debt securities	$	58,777	$	4	$	(74	)	$	58,707
	U.S. agency debt securities	31,800		1		(22		)	31,779
	U.S. government securities	19,982		7		(10		)	19,979
	Total short-term investments	$	110,559	$	12	$	(106	)	$	110,465
Schedule of Contractual Maturity Date of Marketable Securities
		As of
		28-Mar-15		27-Dec-14
	Due within one year	$	99,042	$	90,555
	Due between one and five years	24,060		35,886
	Total cash equivalents and short-term investments	$	123,102	$	126,441

Balance_Sheet_Components_Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 28, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Inventories	Inventories are comprised of the following (in thousands):
		As of
		28-Mar-15			27-Dec-14
	Raw materials	$	319		$	433
	Finished goods	4,307			6,118
	Total inventories	$	4,626		$	6,551
Accrued Liabilities	Accrued liabilities are comprised of the following (in thousands):
		As of
		28-Mar-15			27-Dec-14
	Accrued employee related costs	$	10,701		$	16,021
	Accrued inventory and other purchases	1,625			1,830
	Accrued professional services	661			761
	Other accruals	4,464			4,226
	Total accrued liabilities	$	17,451		$	22,838
Accrued Warranty Liability	Accrued Warranty is comprised of (in thousands):
		Three Months Ended
		28-Mar-15			29-Mar-14
	Accrued warranty balance at beginning of period	$	875		$	686
	Accrual for warranty during the period	275			187
	Actual costs incurred	(219		)	(195		)
	Accrued warranty balance at end of period	$	931		$	678
Deferred Revenue	Deferred revenue is comprised of the following (in thousands):
		As of
		28-Mar-15			27-Dec-14
	Deferred service revenue	$	52,177		$	51,699
	Deferred product revenue	13,851			3,806
	Total deferred revenue	$	66,028		$	55,505
Accumulated Other Comprehensive Income	The following summarizes the activity within accumulated other comprehensive income (loss) (in thousands):
		Accumulated Other Comprehensive Income (Loss)
		Net Unrealized Gains (Losses)			Income Tax			Net Unrealized Gains (Losses),
					Provision			net of tax
	Balance as of December 27, 2014	$	(94	)	$	—		$	(94	)
	Available-for-sale securities:
	Unrealized gains, net	109			—			109
	Total other comprehensive income	109			—			109
	Balance as of March 28, 2015	$	15		$	—		$	15

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 28, 2015
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Lease Payments Under Non-Cancelable Operating Leases	Future minimum lease payments under non-cancelable operating leases as of March 28, 2015 were as follows (in thousands):
	Fiscal Year:
	2015 (remaining nine months)	$	2,574
	2016	3,283
	2017	3,330
	2018	957
	2019	82
	Total	$	10,226

Preferred_Stock_and_Stockholde1

Preferred Stock and Stockholders' Equity (Tables)	3 Months Ended
	Mar. 28, 2015
Equity [Abstract]
Schedule of Share-based Compensation, Stock Options, Activity	The following table summarizes the stock option activity under the Company’s Option Plans:
		Number of		Weighted-			Weighted-	Aggregate
		Stock		Average			Average	Intrinsic
		Options		Exercise			Remaining	Value
		Outstanding		Price			Contractual
							Life (Years)
		(in thousands)
	Balance — December 27, 2014	2,386,412		$	12.91		8.21	$	14,403
	Options granted	408,000		$	21.44
	Options exercised	(172,709	)	$	7.2
	Options canceled	(58,895	)	$	10.38
	Balance — March 28, 2015	2,562,808		$	14.71		7.82	$	18,809
	Vested and expected to vest — March 28, 2015	2,365,419		$	14.41		7.81	$	18,010
	Exercisable — March 28, 2015	957,721		$	11.48		7.67	$	9,884
Schedule of Unvested Restricted Stock Units Roll Forward	The following table summarizes the RSU activity under the Company’s Option Plans:
		Number of		Weighted-			Weighted-	Aggregate
		RSUs		Average			Average	Intrinsic
		Outstanding		Grant Date			Remaining	Value
				Fair Value			Contractual
							Life (Years)
								(in thousands)
	Balance - December 27, 2014	1,731,225		$	18.79		1.27	$	30,245
	RSUs granted	861,107		$	21.3
	RSUs vested	(142,196	)	$	19.36
	RSUs canceled	(121,660	)	$	22.87
	Balance - March 28, 2015	2,328,476		$	19.47		1.46	$	49,131
	Vested and expected to vest — March 28, 2015	2,009,813		$	19.3		1.34	$	42,407
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	The fair values of the option awards and ESPP purchase rights granted and the assumptions used in the Black-Scholes option pricing model are summarized as follows:
		Three Months Ended
		March 28,	March 29,
		2015	2014
	Stock option awards:
	Expected term (in years)	4.6	6.0-6.1
	Risk-free interest rate	1.60%	1.8%-1.9%
	Expected volatility	56.04%	61.90%
	Expected dividend rate	—%	—%
	Grant date fair value per award	$10.11	$17.32 - $17.67
	ESPP purchase right:
	Expected term (in years)	0.50 - 2.0	0.50 - 2.0
	Risk-free interest rate	0.07% - 0.70%	0.1% - 0.3%
	Expected volatility	37.6% - 50.3%	44.8% - 52.7%
	Expected dividend rate	—%	—%
	Grant date fair value per share	$5.48 - $9.18	$8.23 - $13.06
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs	The following table summarizes the stock-based compensation expense recorded in the Company’s condensed consolidated statement of operations (in thousands):
		Three Months Ended
		March 28,			March 29,
		2015			2014
	Cost of revenue	$	549		$	448
	Research and development	2,096			2,599
	Sales and marketing	2,448			2,773
	General and administrative	2,250			2,038
	Total stock-based compensation expense	$	7,343		$	7,858

Net_Loss_per_Share_Tables

Net Loss per Share (Tables)	3 Months Ended
	Mar. 28, 2015
Earnings Per Share [Abstract]
Net Income (Loss) per Share and Weighted-Average Shares	The following table presents the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except per share data):
		Three Months Ended
		28-Mar-15			29-Mar-14
	Numerator:
	Net loss attributable to common stockholders	$	(695	)	$	(8,218	)
	Denominator:
	Weighted average shares used for basic net loss per share computation	32,994			31,734
	Net loss per share attributable to common stockholders :
	Basic	$	(0.02	)	$	(0.26	)
	Diluted	$	(0.02	)	$	(0.26	)
Potentially Dilutive Securities Excluded from Computation of Diluted Net (loss) Income per Common Share	The following shares of potentially dilutive securities were excluded from the computation of diluted net loss per share for the periods presented (in thousands):
		Three Months Ended
		28-Mar-15		29-Mar-14
	Equity awards to purchase common stock	4,891		4,399

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 28, 2015
Segment Reporting [Abstract]
Revenue and Long-Lived Assets by Geographic Region	The following table summarizes the Company’s revenue by geographic region, based on the location to where the product was shipped (in thousands):
		Three Months Ended
		28-Mar-15		29-Mar-14
	United States	$	32,633	$	24,421
	Rest of Americas	3,091		1,697
	Europe, Middle East and Africa	7,482		3,704
	Asia Pacific	3,647		1,938
	Total	$	46,853	$	31,760
	The Company’s long-lived assets by geographic region are summarized as follows (in thousands):
		As of
		28-Mar-15		27-Dec-14
	United States	$	6,947	$	7,218
	Other	158		169
	Total	$	7,105	$	7,387

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Customers Representing Major Revenue and Accounts Receivable (Detail)	3 Months Ended		12 Months Ended
	Mar. 28, 2015	Mar. 29, 2014	Dec. 27, 2014
Total Revenue | Customer A (distributor)
Concentration Risk [Line Items]
Concentration risk	38.00%	48.00%
Total Revenue | Customer B (distributor)
Concentration Risk [Line Items]
Concentration risk	21.00%	13.00%
Accounts Receivable | Customer A (distributor)
Concentration Risk [Line Items]
Concentration risk	41.00%		0.00%
Accounts Receivable | Customer B (distributor)
Concentration Risk [Line Items]
Concentration risk	10.00%		36.00%

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 28, 2015	Mar. 29, 2014	Dec. 27, 2014
Schedule Of Significant Accounting Policies [Line Items]
Inventory write-down	$493,000	$1,810,000
Deferred cost	$1,900,000		$800,000
Product warranties period (in years)	5 years
Minimum
Schedule Of Significant Accounting Policies [Line Items]
Services revenue, recognition period (in years)	1 year
Maximum
Schedule Of Significant Accounting Policies [Line Items]
Services revenue, recognition period (in years)	5 years

Fair_Value_Measurements_Compon

Fair Value Measurements - Components of Cash and Cash Equivalents (Detail) (USD $)	Mar. 28, 2015	Dec. 27, 2014
In Thousands, unless otherwise specified
Cash and cash equivalents:
Cash and cash equivalents	$77,919	$38,941
Short-term investments:
Short-term investments	88,674	110,465
Money market funds
Cash and cash equivalents:
Cash and cash equivalents	34,428	15,976
Corporate debt securities
Short-term investments:
Short-term investments	40,917	58,707
Cash Equivalents
Cash and cash equivalents:
Cash and cash equivalents	34,428	15,976
Cash
Cash and cash equivalents:
Cash and cash equivalents	43,491	22,965
U.S. agency debt securities
Short-term investments:
Short-term investments	27,750	31,779
U.S. government securities
Short-term investments:
Short-term investments	20,007	19,979
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Cash and cash equivalents:
Cash and cash equivalents	34,428	15,976
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash Equivalents
Cash and cash equivalents:
Cash and cash equivalents	34,428	15,976
Significant Other Observable Inputs (Level 2)
Short-term investments:
Short-term investments	88,674	110,465
Significant Other Observable Inputs (Level 2) | Corporate debt securities
Short-term investments:
Short-term investments	40,917	58,707
Significant Other Observable Inputs (Level 2) | Cash Equivalents
Cash and cash equivalents:
Cash and cash equivalents	0	0
Significant Other Observable Inputs (Level 2) | U.S. agency debt securities
Short-term investments:
Short-term investments	27,750	31,779
Significant Other Observable Inputs (Level 2) | U.S. government securities
Short-term investments:
Short-term investments	$20,007	$19,979

Fair_Value_Measurements_Financ

Fair Value Measurements - Financial Instruments Measured at Amortized Costs, Gross Unrealized Gain, Gross Unrealized Loss and Fair Value by Significant Investment Categories (Detail) (USD $)	Mar. 28, 2015	Dec. 27, 2014
In Thousands, unless otherwise specified
Cash and Cash Equivalents
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost Basis	$77,919	$38,941
Fair Value	77,919	38,941
Cash and Cash Equivalents | Money market funds
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost Basis	34,428	15,976
Fair Value	34,428	15,976
Cash and Cash Equivalents | Cash
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost Basis	43,491	22,965
Fair Value	43,491	22,965
Short-term Investments
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost Basis	88,659	110,559
Gross Unrealized Gains	41	12
Gross Unrealized Losses	-26	-106
Fair Value	88,674	110,465
Short-term Investments | Corporate debt securities
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost Basis	40,931	58,777
Gross Unrealized Gains	10	4
Gross Unrealized Losses	-24	-74
Fair Value	40,917	58,707
Short-term Investments | U.S. agency debt securities
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost Basis	27,742	31,800
Gross Unrealized Gains	10	1
Gross Unrealized Losses	-2	-22
Fair Value	27,750	31,779
Short-term Investments | U.S. government securities
Cash And Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost Basis	19,986	19,982
Gross Unrealized Gains	21	7
Gross Unrealized Losses	0	-10
Fair Value	$20,007	$19,979

Fair_Value_Measurements_Contra

Fair Value Measurements - Contractual Maturity Date of Short-Term Investments (Detail) (USD $)	Mar. 28, 2015	Dec. 27, 2014
In Thousands, unless otherwise specified
Contractual Maturity Date of Short-Term Investments [Abstract]
Due within one year	$99,042	$90,555
Due between one and five years	24,060	35,886
Total	$123,102	$126,441

Balance_Sheet_Components_Inven

Balance Sheet Components - Inventories (Detail) (USD $)	Mar. 28, 2015	Dec. 27, 2014
In Thousands, unless otherwise specified
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Raw materials	$319	$433
Finished goods	4,307	6,118
Total inventories	$4,626	$6,551

Balance_Sheet_Components_Accru

Balance Sheet Components - Accrued Liabilities (Detail) (USD $)	Mar. 28, 2015	Dec. 27, 2014
In Thousands, unless otherwise specified
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued employee related costs	$10,701	$16,021
Accrued inventory and other purchases	1,625	1,830
Accrued professional services	661	761
Other accruals	4,464	4,226
Total accrued liabilities	$17,451	$22,838

Balance_Sheet_Components_Accru1

Balance Sheet Components - Accrued Warranty (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
Movement in Standard Product Warranty Accrual [Roll Forward]
Accrued warranty balance at beginning of period	$875	$686
Accrual for warranty during the period	275	187
Actual costs incurred	-219	-195
Accrued warranty balance at end of period	$931	$678

Balance_Sheet_Components_Defer

Balance Sheet Components - Deferred Revenue (Detail) (USD $)	Mar. 28, 2015	Dec. 27, 2014
In Thousands, unless otherwise specified
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$66,028	$55,505
Deferred service revenue
Deferred Revenue Arrangement [Line Items]
Deferred revenue	52,177	51,699
Deferred product revenue
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$13,851	$3,806

Balance_Sheet_Components_Accum

Balance Sheet Components - Accumulated Other Comprehensive Income (Loss) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 28, 2015
Net Unrealized Gains (Losses)
Beginning balance	($94)
Other comprehensive income (loss), before tax	109
Ending balance	15
Income Tax Provision
Beginning balance	0
Other comprehensive income (loss), tax	0
Ending balance	0
Net Unrealized Gains (Losses), net of tax
Beginning balance	-94
Other comprehensive income (loss)	109
Accumulated other comprehensive income (loss)	15
Accumulated Net Unrealized Investment Gain (Loss)
Net Unrealized Gains (Losses)
Other comprehensive income (loss), before tax	109
Net Unrealized Gains (Losses), net of tax
Other comprehensive income (loss)	$109

Commitments_and_Contingencies_1

Commitments and Contingencies - Future Minimum Lease Payments Under Non-Cancelable Operating Leases (Detail) (USD $)	Mar. 28, 2015
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
2015 (remaining nine months)	$2,574
2016	3,283
2017	3,330
2018	957
2019	82
Total	$10,226

Commitments_and_Contingencies_2

Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014	Dec. 27, 2014
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$0.80	$0.80
Purchase commitments with vendors	$5.60		$3.60

Preferred_Stock_and_Stockholde2

Preferred Stock and Stockholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 28, 2015	Dec. 27, 2014	31-May-13
Schedule Of Stockholders Equity [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	2,562,808	2,386,412
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, par value	$0.00	$0.00
Common Stock votes per share	$1
Common stock, shares issued	33,170,852	32,641,500
Common stock, shares outstanding	33,170,852	32,641,500
Treasury stock, outstanding	8,109,848	8,109,848
Treasury stock, value	$12,469	$12,469
Treasury stock,value per share	$1.53	$1.53
Performance Shares
Schedule Of Stockholders Equity [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	34,151	36,495
2013 Equity Plan
Schedule Of Stockholders Equity [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	1,464,740	1,464,740	2,929,481

Preferred_Stock_and_Stockholde3

Preferred Stock and Stockholders' Equity - Shares Available for Future Grants Under Option Plan (Detail)	1 Months Ended	3 Months Ended
	31-May-13	Mar. 28, 2015	Dec. 27, 2014
Unit Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Description		Vested options may be exercised up to ten years from the vesting commencement date, as defined in the Option Plan. Vested but unexercised options, under the Option Plan, expire 30 days after termination of employment with the Company.
2013 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	2,929,481	1,464,740	1,464,740
Other increase	4,967,172
Share-based Compensation Arrangement by Share-based Payment Award, Description		(i) 1,464,740 shares, (ii) 5% of the outstanding shares of common stock as of the last day of the immediately preceding fiscal year, or (iii) such other amount as determined by the Board. Vested but unexercised options, under the 2013 Equity Plan, expire three months after termination of service with the Company.
Number Of Additional Shares Allowable For Future Authorization Each Year	1,464,740
Percentage of Outstanding Stock Maximum	5.00%
Maximum Exercisable Term For General Termination	3 months
Common Stock | 2013 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance		1,570,411
Common Stock | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance		3,320,873

Preferred_Stock_and_Stockholde4

Preferred Stock and Stockholders' Equity - 2013 Equity Incentive Plan and ESPP (Details) (USD $)	1 Months Ended	3 Months Ended		12 Months Ended
In Thousands, except Share data, unless otherwise specified	Jun. 29, 2013	Mar. 28, 2015	Mar. 29, 2014	Dec. 27, 2014	31-May-13
	Period	Period
Employee Stock Purchase Plan [Abstract]
Share-based compensation Expense		$7,343	$7,858
Employee Stock
2013 Equity Incentive Plan [Abstract]
Number of shares authorized		439,422			439,422
Number of Additional Shares Authorized				439,422
Employee Stock Purchase Plan [Abstract]
Employee Stock Ownership Plan (ESOP), Plan Description		The ESPP provides for a 24-month offering period comprised of four purchase periods of approximately six months. Employees are able to purchase shares at 85% of the lower of the market value of the Company's common stock (i) at the date of commencement of the offering period or (ii) at the last day of the purchase period.
Share-based compensation Expense		$700	$1,700
Employee Stock Purchase Plan Maximum Percentage Of Compensation To Purchase Shares By Eligible Participants		15.00%
Employee Stock Purchase Plan Percentage Of Purchase Price From Market Value		85.00%
Employee Stock Purchase Plan Offered Period				24 months
Number of Purchase Periods	4	1
Term of Purchase Period	6 months
Shares Issued in Period		273,301
Per Share Weighted Average Price of Shares Purchased		$9.54
2013 Equity Plan
2013 Equity Incentive Plan [Abstract]
Number of shares authorized		1,464,740		1,464,740	2,929,481

Preferred_Stock_and_Stockholde5

Preferred Stock and Stockholders' Equity - Stock Option Activity (Detail) (USD $)	3 Months Ended		12 Months Ended	1 Months Ended	0 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014	Dec. 27, 2014	31-May-13	Apr. 30, 2013
Number of Stock Options Outstanding
Number of stock options outstanding, beginning of period	2,386,412
Number of stock options outstanding, granted	408,000
Number of stock options outstanding, Options exercised	-172,709
Number of stock options outstanding, cancelled	-58,895
Number of stock options outstanding, end of period	2,562,808		2,386,412
Vested and expected to vest	2,365,419
Exercisable	957,721
Weighted-average exercise price per award, Weighted - Average Exercise Price
Weighted-average exercise price, beginning of period	$12.91
Weighted-average exercise price, options granted	$21.44
Weighted-average exercise price, options exercised	$7.20
Weighted-average exercise price, options cancelled	$10.38
Weighted-average exercise price, end of period	$14.71		$12.91
Vested and expected to vest	$14.41
Exercisable	$11.48
Weighted-average remaining contractual life (years)
Weighted average remaining contractual life	7 years 9 months 25 days		8 years 2 months 15 days
Vested and expected to vest	7 years 9 months 21 days
Exercisable	7 years 8 months 1 day
Aggregate Intrinsic Value
Aggregate intrinsic value	$18,809		$14,403
Vested and expected to vest	18,010
Exercisable	$9,884
Weighted average fair value (in dollar per share)	$10.76	$11.48
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Description	Vested options may be exercised up to ten years from the vesting commencement date.
Restricted Stock Units (RSUs)
Aggregate Intrinsic Value
Share Price (in dollar per share)	$21.10		$17.47
Performance Shares
Number of Stock Options Outstanding
Number of stock options outstanding, end of period	34,151		36,495
2013 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Description	(i) 1,464,740 shares, (ii) 5% of the outstanding shares of common stock as of the last day of the immediately preceding fiscal year, or (iii) such other amount as determined by the Board. Vested but unexercised options, under the 2013 Equity Plan, expire three months after termination of service with the Company.
2013 Equity Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
Award Vesting Rights, Percentage				25.00%
Expiration Period				10 years
Expiration Period After Termination of Employment				3 months
2015 Equity PLan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration Period	7 years
2012 Equity Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration Period After Termination of Employment					30 days

Preferred_Stock_and_Stockholde6

Preferred Stock and Stockholders' Equity - Restricted Stock Units Activity (Detail) (Restricted Stock Units (RSUs), USD $)	3 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 28, 2015	Dec. 27, 2014
Number of RSUs Outstanding
Number of outstanding, Beginning Balances	1,731,225
Number of outstanding, granted	861,107
Number of outstanding, vested	-142,196
Number of outstanding, cancelled	-121,660
Number of outstanding, Ending balance	2,328,476	1,731,225
Vested and expected to vest	2,009,813
Weighted-Average Grant Date Fair Value
Weighted-Average Base Price, Beginning Balances	$18.79
Weighted-average grant date fair value, granted (in dollar per share)	$21.30
Weighted-average grant date fair value, vested (in dollar per share)	$19.36
Weighted-average grant date fair value, cancelled (in dollar per share)	$22.87
Weighted-Average Base Price, Ending Balances	$19.47	$18.79
Vested and expected to vest	$19.30
Weighted-Average Remaining Contractual Life (Years)
Weighted-average remaining contractual life	1 year 5 months 15 days	1 year 3 months 7 days
Vested and expected to vest	1 year 4 months 2 days
Aggregate Intrinsic Value
Aggregate intrinsic value	$49,131	$30,245
Vested and expected to vest	$42,407
Share Price (in dollar per share)	$21.10	$17.47
Minimum
Reconciliation of Restricted Stock Activity [Line Items]
Vesting period		1 year
Maximum
Reconciliation of Restricted Stock Activity [Line Items]
Vesting period		4 years

Preferred_Stock_and_Stockholde7

Preferred Stock and Stockholders' Equity - Stock-Based Compensation Expense (Detail) (USD $)	3 Months Ended
	Mar. 28, 2015	Mar. 29, 2014	Dec. 27, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Shares outstanding	2,562,808		2,386,412
Share-based compensation Expense	$7,343,000	$7,858,000
Cost of Sales
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Share-based compensation Expense	549,000	448,000
Research and Development Expense
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Share-based compensation Expense	2,096,000	2,599,000
Selling and Marketing Expense
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Share-based compensation Expense	2,448,000	2,773,000
General and Administrative Expense
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Share-based compensation Expense	2,250,000	2,038,000
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term (in years)	4 years 7 months 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	1.60%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	56.04%	61.90%
Expected dividend rate	0.00%	0.00%
Grant date fair value per award, stock options (in dollar per share)	$10.11
Unrecognized compensation expense	7,000,000
Stock options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term (in years)		6 years
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate		1.80%
Grant date fair value per award, stock options (in dollar per share)		$17.32
Stock options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term (in years)		6 years 1 month 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate		1.90%
Grant date fair value per award, stock options (in dollar per share)		$17.67
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected dividend rate	0.00%	0.00%
Unrecognized compensation expense	2,500,000
Share-based compensation Expense	700,000	1,700,000
Employee Stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term (in years)	6 months	6 months
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	0.07%	0.10%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	37.60%	44.80%
Grant date fair value per share, ESPP (in dollar per share)	$5.48	$8.23
Employee Stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term (in years)	2 years	2 years
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	0.70%	0.30%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	50.30%	52.70%
Grant date fair value per share, ESPP (in dollar per share)	$9.18	$13.06
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Number of outstanding, granted	861,107
Weighted-average grant date fair value, granted (in dollar per share)	$21.30
Unrecognized compensation expense	$24,200,000

Defined_Contribution_Plans_Add

Defined Contribution Plans - Additional Information (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
Postemployment Benefits [Abstract]
Contributions to 401(k) defined contribution plan	$415	$658

Income_Tax_Additional_Informat

Income Tax - Additional Information (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
Income Tax Disclosure [Abstract]
Income tax (provision) benefit	($88)	$3,700

Net_Loss_per_Share_Computation

Net Loss per Share - Computation of Basic and Diluted Net Loss Per Share (Detail) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
Numerator:
Net loss attributable to common stockholders	($695)	($8,218)
Denominator:
Weighted average shares used for basic loss per share computation	32,994	31,734
Net (loss) income per share attributable to common stockholders :
Basic (in dollars per share)	($0.02)	($0.26)
Diluted (in dollars per share)	($0.02)	($0.26)

Net_Loss_per_Share_Potentially

Net Loss per Share - Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss Per Common Stock (Detail) (Option Plans' awards to purchase common stock)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
Option Plans' awards to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per unit	4,891	4,399

Segment_Information_Additional

Segment Information - Additional Information (Detail)	3 Months Ended
	Mar. 28, 2015
	Segment
Segment Reporting [Abstract]
Number of segments	1

Segment_Information_Revenue_an

Segment Information - Revenue and Long-Lived Assets by Geographic Region (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014	Dec. 27, 2014
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	$46,853	$31,760
Long-lived assets	7,105		7,387
United States
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	32,633	24,421
Long-lived assets	6,947		7,218
Rest of Americas
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	3,091	1,697
Europe, Middle East and Africa
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	7,482	3,704
Asia Pacific
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	3,647	1,938
Other
Segment Reporting Revenue Reconciling Item [Line Items]
Long-lived assets	$158		$169