Infinera (INFN) 10-Q 10 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 02, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Trading Symbol	INFN
Entity Registrant Name	INFINERA CORP
Entity Central Index Key	1,138,639
Current Fiscal Year End Date	--12-29
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding (in shares)		151,280,586

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 30, 2017
Current assets:
Cash and cash equivalents	$ 151,436	$ 116,345
Short-term investments	112,886	147,596
Accounts receivable, net of allowance for doubtful accounts of $916 in 2018 and $892 in 2017	161,541	126,152
Inventory	215,888	214,704
Prepaid expenses and other current assets	44,362	43,140
Total current assets	686,113	647,937
Property, plant and equipment, net	135,196	135,942
Intangible assets	83,958	92,188
Goodwill	192,562	195,615
Long-term investments	18,383	31,019
Cost-method investment	5,110	5,110
Other non-current assets	11,335	9,859
Total assets	1,132,657	1,117,670
Current liabilities:
Accounts payable	77,776	58,124
Accrued expenses	51,955	39,782
Accrued compensation and related benefits	46,911	45,751
Short-term debt, net	147,946	144,928
Accrued warranty	14,022	13,670
Deferred revenue	58,460	72,421
Total current liabilities	397,070	374,676
Accrued warranty, non-current	16,826	17,239
Deferred revenue, non-current	13,181	22,502
Deferred tax liability	19,398	21,609
Other long-term liabilities	14,973	16,279
Commitments and contingencies (Note 17)
Stockholders’ equity:
Preferred stock	0	0
Common stock	151	149
Additional paid-in capital	1,438,700	1,417,043
Accumulated other comprehensive income	1,313	6,254
Accumulated deficit	(768,955)	(758,081)
Total stockholders' equity	671,209	665,365
Total liabilities and stockholders’ equity	$ 1,132,657	$ 1,117,670

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 30, 2017
Statement of Financial Position [Abstract]
Net of allowance for doubtful accounts	$ 916	$ 892
Preferred stock, par value (in usd per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in usd per share)	$ 0.001	$ 0.001
Common stock, authorized shares (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	151,163,000	149,471,000
Common stock, shares outstanding (in shares)	151,163,000	149,471,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Revenue:
Product	$ 171,629	$ 147,053
Services	31,052	28,469
Total revenue	202,681	175,522
Cost of revenue:
Cost of product	107,665	99,332
Cost of services	12,831	12,134
Restructuring and other related costs	17	0
Total cost of revenue	120,513	111,466
Gross profit	82,168	64,056
Operating expenses:
Research and development	58,681	55,083
Sales and marketing	30,492	29,441
General and administrative	17,836	17,359
Restructuring and other related credit	(163)	0
Total operating expenses	106,846	101,883
Loss from operations	(24,678)	(37,827)
Other income (expense), net:
Interest income	897	751
Interest expense	(3,683)	(3,403)
Other gain (loss), net	506	(130)
Total other income (expense), net	(2,280)	(2,782)
Loss before income taxes	(26,958)	(40,609)
Benefit from income taxes	(678)	(158)
Net loss	$ (26,280)	$ (40,451)
Net loss per common share:
Basic (in usd per share)	$ (0.17)	$ (0.28)
Diluted (in usd per share)	$ (0.17)	$ (0.28)
Weighted average shares used in computing net loss per common share:
Basic (in shares)	150,333	145,786
Diluted (in shares)	150,333	145,786

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (26,280)	$ (40,451)
Other comprehensive income (loss), net of tax:
Unrealized loss on available-for-sale investments	(125)	(82)
Foreign currency translation adjustment	(4,816)	6,217
Net change in accumulated other comprehensive income (loss)	(4,941)	6,135
Comprehensive loss	$ (31,221)	$ (34,316)

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2018		Apr. 01, 2017		Dec. 30, 2017	Mar. 31, 2018		Dec. 30, 2017	Apr. 01, 2017
Cash Flows from Operating Activities:
Net loss	$ (26,280)		$ (40,451)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	16,976		15,951
Non-cash restructuring and other related credits	(81)		0
Amortization of debt discount and issuance costs	3,018		2,730
Impairment of intangible assets	0		252
Stock-based compensation expense	10,983		10,877
Other loss (gain)	84		60
Changes in assets and liabilities:
Accounts receivable	(30,928)		26,366
Inventory	(2,329)		(326)
Prepaid expenses and other assets	(3,950)		(5,767)
Accounts payable	19,286		(3,180)
Accrued liabilities and other expenses	(6,181)		(16,425)
Deferred revenue	5,293		12,943
Net cash provided by (used in) operating activities	(14,109)		3,030
Cash Flows from Investing Activities:
Purchase of available-for-sale investments	(2,986)		(84,422)
Proceeds from maturities of investments	50,168		46,679
Purchase of property and equipment	(8,019)		(14,743)
Net cash provided by (used in) investing activities	39,163		(52,486)
Cash Flows from Financing Activities:
Acquisition of noncontrolling interest	0		(471)
Proceeds from issuance of common stock	10,644		9,808
Minimum tax withholding paid on behalf of employees for net share settlement	(97)		(151)
Net cash provided by financing activities	10,547		9,186
Effect of exchange rate changes on cash and restricted cash	(58)		1,337
Net change in cash, cash equivalents and restricted cash	35,543		(38,933)
Cash, cash equivalents and restricted cash at beginning of period	121,486		177,580		$ 177,580
Cash, cash equivalents and restricted cash at end of period	121,486		177,580		177,580	$ 157,029	[1]	$ 121,486	$ 138,647	[1]
Supplemental disclosures of cash flow information:
Cash paid for income taxes, net of refunds	1,537		1,553
Cash paid for interest	9		3
Supplemental schedule of non-cash investing activities:
Transfer of inventory to fixed assets	893		138
Restricted Cash and Cash Equivalents [Abstract]
Cash and cash equivalents						151,436		$ 116,345	125,658
Short-term restricted cash						84			7,908
Long-term restricted cash						$ 5,509			$ 5,081
Total cash, cash equivalents and restricted cash	$ 157,029	[1]	$ 138,647	[1]	$ 121,486
[1]	Reconciliation of cash, cash equivalents and restricted cash to the condensed consolidated balance sheets: March 31, 2018 April 1, 2017 (In thousands)Cash and cash equivalents$151,436 $125,658Short-term restricted cash84 7,908Long-term restricted cash5,509 5,081Total cash, cash equivalents and restricted cash$157,029 $138,647

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	Basis of Presentation and Significant Accounting Policies Basis of Presentation Infinera Corporation (the “Company”) prepared its interim condensed consolidated financial statements that accompany these notes in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”) and pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (the “SEC”), consistent in all material respects with those applied in the Company’s Annual Report on Form 10-K for the fiscal year ended December 30, 2017 . The Company has made certain estimates, assumptions and judgments that can affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the condensed consolidated financial statements, as well as the reported amounts of revenue and expenses during the periods presented. Significant estimates, assumptions and judgments made by management include revenue recognition, stock-based compensation, inventory valuation, accrued warranty, business combinations, fair value measurement of investments and accounting for income taxes. Other estimates, assumptions and judgments made by management include allowances for sales returns, allowances for doubtful accounts, useful life of intangible assets, property, plant and equipment, and fair value measurement of the liability component of the Company's $150.0 million in aggregate principal amount of 1.75% convertible senior notes due June 1, 2018 (the “Notes”). Management believes that the estimates and judgments upon which they rely are reasonable based upon information available to them at the time that these estimates and judgments are made. To the extent there are material differences between these estimates and actual results, the Company’s condensed consolidated financial statements will be affected. The interim financial information is unaudited, but reflects all adjustments that are, in management’s opinion, necessary to provide a fair presentation of results for the interim periods presented. All adjustments are of a normal recurring nature. The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated. This interim information should be read in conjunction with the consolidated financial statements in the Company’s Annual Report on Form 10-K for the fiscal year ended December 30, 2017 . To date, a few of the Company’s customers have accounted for a significant portion of its revenue. For the three months ended March 31, 2018 , two customers individually accounted for 29% and 11% of the Company's total revenue and for the corresponding period in 2017, one customer accounted for 19% of the Company's total revenue. There have been no material changes in the Company’s significant accounting policies for the three months ended March 31, 2018 as compare d to those disclosed in the Company’s Annual Report on Form 10-K for the fiscal year ended December 30, 2017 , with the exception of the Company's revenue recognition policy. Effective December 31, 2017, the Company adopted Accounting Standards Update No. 2014-09, "Revenue from Contracts with Customers (Topic 606)” (“ASC 606”). See Note 3, “Revenue Recognition” to the Notes to Condensed Consolidated Financial Statements for discussion on the impact of the adoption of these standards on the Company's policy for revenue recognition. The Company adopted Accounting Standards Update 2016-18, “Statement of Cash Flows (Topic 230): Restricted Cash” (“ASU 2016-18”), during the first quarter of fiscal 2018, using the retrospective transition approach. Restricted cash in the prior period has been included with cash and cash equivalents when reconciling the beginning and ending total amounts on the statement of cash flows for the three months ended April 1, 2017, to conform to the current period presentation. The adoption of ASU 2016-18 did not have a material impact on the cash flow activity presented on the Company's condensed consolidated statement of cash flows.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting Pronouncements Recently Adopted In December 2017, the SEC staff issued Staff Accounting Bulletin No. 118, “Income Tax Accounting Implications of the Tax Cuts and Jobs Act" (“SAB 118”), which allows the Company to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. Since the U.S. Tax Cuts and Jobs Act (the “Tax Act”) was passed in December 2017, and ongoing guidance and accounting interpretation are expected over the next 12 months, the Company considers the accounting of the transition tax and deferred tax re-measurements to be incomplete due to the forthcoming guidance and the ongoing analysis of final year-end data and tax positions. The Company expects to complete the analysis within the measurement period in accordance with SAB 118. In March 2018, the Financial Accounting Standards Board (the “FASB”) issued ASU 2018-05, Amendments to SEC Paragraphs Pursuant to SAB 118 and added such SEC guidance to Accounting Standards Codification 740, “Income Taxes, codified under the title: Income Tax Accounting Implications of the Tax Cuts and Jobs Act.” In May 2017, the FASB issued Accounting Standards Update 2017-09, “Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting” (“ASU 2017-09”), which amends the scope of modification accounting for share-based payment arrangements, and provides guidance on the types of changes to the terms or conditions of share-based payment awards to which an entity would be required to apply modification accounting under Topic 718. The Company's adoption of ASU 2017-09 during its first quarter of 2018 had no impact on its condensed consolidated financial statements. In November 2016, the FASB issued ASU 2016-18, which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents and amounts generally described as restricted cash or restricted cash equivalents. As such, restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and ending-of-period total amounts shown on the statement of cash flows. The Company adopted ASU 2016-18 during the first quarter of fiscal 2018, using the retrospective transition approach. See the condensed consolidated statements of cash flows for a reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets that sum to the total of the same such amounts on the condensed consolidated statements of cash flows. In May 2016, the FASB issued Accounting Standards Update 2016-11, “Revenue Recognition (Topic 605) and Derivatives and Hedging (Topic 815): Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09 and 2014-16 Pursuant to Staff Announcements at the March 3, 2016 EITF Meeting (SEC Update)” (“ASU 2016-11”), which rescinds various standards codified as part of Topic 605, Revenue Recognition in relation to the future adoption of Topic 606. These rescissions include changes to topics pertaining to revenue and expense recognition for freight services in process, accounting for shipping and handling fees and costs, and accounting for consideration given by a vendor to a customer. The Company adopted ASU 2016-11 during the first quarter of 2018. See Note 3, “Revenue Recognition” to the Notes to Condensed Consolidated Financial Statements for more information. In May 2014, the FASB issued ASC 606, which creates a single, joint revenue standard that is consistent across all industries and markets for companies that prepare their financial statements in accordance with U.S. GAAP. Under ASC 606, an entity is required to recognize revenue upon the transfer of promised goods or services to customers in an amount that reflects the consideration the entity expects to be entitled to receive in exchange for those goods or services. In August 2015, the FASB issued Accounting Standards update 2015-14, “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date,” which deferred the effective date of ASC 606 by one year with early adoption permitted beginning after December 15, 2016. The updated standard is effective for interim and annual periods beginning after December 15, 2017. In April 2016, the FASB issued Accounting Standards Update 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing,” which clarifies the implementation guidance on identifying performance obligations and licensing. In May 2016, the FASB issued Accounting Standards Update 2016-12, “Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients,” which amends the guidance on collectability, noncash consideration, presentation of sales tax and transition. In December 2016, the FASB issued Accounting Standards Update 2016-20, “Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers,” to increase stakeholders' awareness of the proposals and to expedite improvements to ASC 606. ASC 606 also includes Subtopic 340-40, “Other Assets and Deferred Costs - Contracts with Customers,” which requires the deferral of incremental costs of obtaining a contract with a customer. Collectively, the Company refers to ASC 606 and Subtopic 340-40 as “ASC 606.” The Company adopted ASC 606 as of December 31, 2017 using the modified retrospective transition method applied to those contracts that were not completed as of December 31, 2017. See Note 3, “Revenue Recognition” to the Notes to Condensed Consolidated Financial Statements for more information. Accounting Pronouncements Not Yet Effective In January 2017, the FASB issued Accounting Standards Update 2017-04, “Simplifying the Test for Goodwill Impairment” (“ASU 2017-04”). The guidance eliminates Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. A goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The same one-step impairment test will be applied to goodwill at all reporting units, even those with zero or negative carrying amounts. Entities will be required to disclose the amount of goodwill at reporting units with zero or negative carrying amounts. ASU 2017-04 will be effective for the Company's annual or any interim goodwill impairment tests in its first quarter of fiscal 2020. The Company is currently evaluating the impact the adoption of ASU 2017-04 will have on its consolidated financial statements. In June 2016, the FASB issued Accounting Standards Update 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”), which requires measurement and recognition of expected credit losses for financial assets held. This guidance is effective for the Company in its first quarter of fiscal 2020 and early adoption is permitted. The Company is currently evaluating the impact the adoption of ASU 2016-13 will have on its consolidated financial statements. In February 2016, the FASB issued Accounting Standards Update 2016-02, “Leases (Topic 842)” (“ASU 2016-02”), which amends the existing accounting standards for leases. The new standard requires lessees to record a right-of-use asset and a corresponding lease liability on the balance sheet (with the exception of short-term leases). For lessees, leases will continue to be classified as either operating or financing in the income statement. This guidance is effective for the Company in its first quarter of fiscal 2019 and early adoption is permitted. ASU 2016-02 is required to be applied with a modified retrospective approach and requires application of the new standard at the beginning of the earliest comparative period presented. The Company is currently evaluating the impact the adoption of ASU 2016-02 will have on its consolidated financial statements and expects to have increases in the assets and liabilities of its consolidated balance sheets.

Revenue Recognition

Revenue Recognition	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition Effective December 31, 2017, the Company adopted ASC 606, using the modified retrospective method applied to those contracts that were not completed as of December 31, 2017. Results for the reporting periods after December 31, 2017 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with the Company’s historical accounting under Topic 605. The Company recognizes revenue when control of the promised goods or services is transferred to its customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company determines revenue recognition by applying the following five-step approach: • identification of the contract, or contracts, with a customer; • identification of the performance obligations in the contract; • determination of the transaction price; • allocation of the transaction price to the performance obligations in the contract; and • recognition of revenue when, or as, the Company satisfies a performance obligation. Many of the Company's product sales are sold in combination with installation and deployment services along with initial hardware and software support. The Company's product sales are also sold with spares management, on-site hardware replacement services, network management operations, software subscription, extended hardware warranty or training. Initial software and hardware support services are generally delivered over a one-year period in connection with the initial purchase. Software warranty provides customers with maintenance releases during the warranty support period and hardware warranty provides replacement or repair of equipment that fails to perform in line with specifications. Software subscription service includes software warranty and additionally provides customers with rights to receive unspecified software product upgrades released during the support period. Spares management and on-site hardware replacement services include the replacement of defective units at customer sites in accordance with specified service level agreements. Network operations management includes the day-to-day operation of a customer's network. These services are generally delivered on an annual basis. The Company evaluates each promised good and service in a contract to determine whether it represents a distinct performance obligation or should be accounted for as a combined performance obligation. Services revenue includes software subscription services, installation and deployment services, spares management, on-site hardware replacement services, network operations management, extended hardware warranty services and training. Revenue from software subscription, spares management, on-site hardware replacement services, network operations management and extended hardware warranty contracts is deferred and is recognized ratably over the contractual support period, which is generally one year, as services are provided over the course of the entire period. Revenue related to training and installation and deployment services is recognized upon completion of the services. Contracts and customer purchase orders are generally used to determine the existence of an arrangement. In addition, shipping documents and customer acceptances, when applicable, are used to verify delivery and transfer of title. The Company typically satisfies its performance obligations upon shipment or delivery of product depending on the contractual terms. Payment terms to customers generally range from net 30 to 120 days from invoice, which are considered to be standard payment terms. The Company assesses its ability to collect from its customers based primarily on the creditworthiness and past payment history of the customer. Customer product returns are approved on a case by case basis. Specific reserve provisions are made based upon a specific review of all the approved product returns where the customer has yet to return the products to generate the related sales return credit at the end of a period. Estimated sales returns are recorded as a reduction to revenue. For sales to resellers, the same revenue recognition criteria apply. It is the Company’s practice to identify an end-user prior to shipment to a reseller. The Company does not offer rights of return or price protection to its resellers. The Company reports revenue net of any required taxes collected from customers and remitted to government authorities, with the collected taxes recorded as current liabilities until remitted to the relevant government authority. ASC 606 Adoption The Company recorded a net reduction to the opening balance of its accumulated deficit of $15.4 million as of December 31, 2017 due to the cumulative impact of adopting ASC 606, with the impact primarily related to its services revenue. The impact to revenue for the three months ended March 31, 2018 was a decrease of $3.2 million as a result of applying ASC 606. The details of the significant changes and quantitative impact of the Company’s adoption of ASC 606 are set out below. Customer Purchase Commitments The Company makes available software licenses that are non-essential to the functionality of the hardware by providing customers the ability to purchase incremental bandwidth capacity. Line modules generally include a specific initial capacity and incremental capacity can be added by the purchase of Infinera Instant Bandwidth (“IB”) licenses. IB licenses are considered distinct performance obligations because customers can provision additional transmission capacity on demand without the deployment of any incremental equipment. Some contracts commit the customer to purchase incremental IB licenses within a specified time frame from the initial line module shipment. The time frame varies by customer and ranges between 12 to 24 months. If the customer does not purchase the additional capacity within the time frame as stated in the contract, the Company has the right to deliver and invoice such IB licenses to the customer. Under ASC 605, the additional incremental licenses were not included as an element of the initial arrangement because fees for the future purchase were not fixed. Under ASC 606, future committed licenses are considered to be additional performance obligations when a minimum purchase obligation is present, as evidenced by enforceable rights and obligations. As such, the Company is required to estimate the variable consideration for future IB licenses as part of determining the contract transaction price. Contract Termination Rights The contract term is determined on the basis of the period over which the parties to the contract have present enforceable rights and obligations. Certain customer contracts include a termination for convenience clause that allows the customer to terminate services without penalty, upon advance notification. The Company concluded that the duration of support contracts do not extend beyond the non-cancellable portion of the contract. Variable Consideration The consideration associated with customer contracts is generally fixed. Variable consideration includes discounts, rebates, refunds, credits, incentives, penalties, or other similar items. The amount of consideration that can vary is not a substantial portion of total consideration . Variable consideration estimates will be re-assessed at each reporting period until a final outcome is determined. The changes to the original transaction price due to a change in estimated variable consideration will be applied on a retrospective basis, with the adjustment recorded in the period in which the change occurs. Changes to variable consideration will be tracked and material changes disclosed. Stand-alone Selling Price Stand-alone selling price is the price at which an entity would sell a good or service on a stand-alone (or separate) basis at contract inception. Under the model, the observable price of a good or service sold separately provides the best evidence of stand-alone selling price. However, in certain situations, stand-alone selling prices will not be readily observable and the entity must estimate the stand-alone selling price. When allocating on a relative stand-alone selling price basis, any discount provided in the contract is generally allocated proportionately to all of the performance obligations in the contract. The majority of products and services offered by the Company have readily observable selling prices. For products and services that do not, the Company generally estimates stand-alone selling price using the market assessment approach based on expected selling price and adjusts those prices as necessary to reflect the Company’s costs and margins. As part of its stand-alone selling price policy, the Company reviews product pricing on a periodic basis to identify any significant changes and revise its expected selling price assumptions as appropriate. Shipping and Handling The Company treats shipping and handling activities as costs to fulfill the Company's promise to transfer products. Shipping and handling fees billed to customers are recorded as a reduction to cost of product. Capitalization of Costs to Obtain a Contract The Company has assessed the treatment of costs to obtain or fulfill a contract with a customer. Sales commissions have historically been expensed as incurred. Under ASC 606, the Company capitalizes sales commissions related to multi-year service contracts and amortizes the asset over the period of benefit, which is the service period. Sales commissions paid on contract renewals, including service contract renewals, is commensurate with the sales commissions paid on the initial contracts. The Company elected ASC 606's practical expedient to expense sales commissions as incurred when the amortization period of the related contract term is one year or less. These costs are recorded as sales and marketing expense and included on the balance sheet as accrued compensation and related benefits until paid. As of March 31, 2018, the ending balance of the Company’s capitalized costs to obtain a contract was $0.5 million . The Company's amortization expense was not material for the three months ended March 31, 2018. Disaggregation of Revenue The following table presents the Company's revenue disaggregated by revenue source (in thousands): Three Months Ended March 31, 2018 April 1, 2017 (1) Product $ 171,629 $ 147,053 Services 31,052 28,469 Total revenue $ 202,681 $ 175,522 The following tables present the Company's revenue disaggregated by geography, based on the shipping address of the customer, and by customer channel (in thousands): Three Months Ended March 31, 2018 April 1, 2017 (1) United States $ 129,025 $ 99,780 Other Americas 5,215 6,035 Europe, Middle East and Africa 59,199 57,413 Asia Pacific 9,242 12,294 Total revenue $ 202,681 $ 175,522 Three Months Ended March 31, 2018 April 1, 2017 (1) Direct $ 188,462 $ 165,946 Indirect 14,219 9,576 Total revenue $ 202,681 $ 175,522 (1) Prior period amounts have not been adjusted under the modified retrospective method. Contract Balances The following table provides information about receivables, contract assets and contract liabilities from contracts with customers (in thousands): March 31, 2018 At Adoption Accounts receivable, net $ 161,541 $ 135,245 Contract assets $ 2,670 $ 2,825 Deferred revenue $ 71,641 $ 75,458 Revenue recognized for the three months ended March 31, 2018 that was included in the deferred revenue balance at the beginning of the reporting period was $14.5 million . Changes in the contract asset and liability balances during the three months ended March 31, 2018 were not materially impacted by other factors. Transaction Price Allocated to the Remaining Performance Obligation The Company’s remaining performance obligations represent the transaction price allocated to performance obligations that are unsatisfied or partially satisfied, consisting of deferred revenue and backlog. The Company’s backlog represents purchase orders received from customers for future product shipments and services. The Company’s backlog is subject to future events that could cause the amount or timing of the related revenue to change, and, in certain cases, may be canceled without penalty. Orders in backlog may be fulfilled several quarters following receipt or may relate to multi-year support service obligations. The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied (or partially satisfied) at the end of the reporting period (in thousands): Remainder of 2018 2019 2020 2021 2022 Thereafter Total Revenue expected to be recognized in the future as of March 31, 2018 $ 167,860 $ 16,382 $ 13,040 $ 2,716 $ 1,972 $ 1,876 $ 203,846 Impacts on Financial Statements The following tables summarize the impacts of adopting ASC 606 on the Company's condensed consolidated statement of operations for the three months ended March 31, 2018 and the Company's condensed consolidated balance sheet as of December 31, 2017 (in thousands): Three Months Ended March 31, 2018 As Reported Adjustments Balances Without Adoption of ASC 606 Income Statement Revenue Product $ 171,629 $ 1,944 $ 173,573 Services 31,052 1,282 32,334 $ 202,681 $ 3,226 $ 205,907 Costs and expenses Cost of revenue $ 120,513 $ 528 $ 121,041 Net loss $ (26,280 ) $ 2,698 $ (23,582 ) Balance at December 30, 2017 Adjustments due to ASC 606 As Adjusted Balance at December 31, 2017 Balance Sheet Assets Accounts receivable, net $ 126,152 $ 9,093 $ 135,245 Inventory $ 214,704 $ (239 ) $ 214,465 Prepaid expenses and other assets $ 43,339 $ 2,731 $ 46,070 Liabilities Accrued expenses $ 39,782 $ 15,645 $ 55,427 Deferred revenue $ 94,923 $ (19,465 ) $ 75,458 Equity Accumulated deficit $ (758,081 ) $ 15,406 $ (742,675 )

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Pursuant to the accounting guidance for fair value measurements and its subsequent updates, fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, the Company considers the principal or most advantageous market in which it would transact and it considers assumptions that market participants would use when pricing the asset or liability. Valuation techniques used by the Company are based upon observable and unobservable inputs. Observable or market inputs reflect market data obtained from independent sources, while unobservable inputs reflect the Company’s assumptions about market participant assumptions based on the best information available. Observable inputs are the preferred source of values. These two types of inputs create the following fair value hierarchy: Level 1 – Quoted prices in active markets for identical assets or liabilities. Level 2 – Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 – Prices or valuations that require management inputs that are both significant to the fair value measurement and unobservable. The Company measures its cash equivalents, foreign currency exchange forward contracts and marketable debt securities at fair value and classifies its investments in accordance with the fair value hierarchy. The Company’s money market funds and U.S. treasuries are classified within Level 1 of the fair value hierarchy and are valued based on quoted prices in active markets for identical securities. The Company classifies its certificates of deposit, commercial paper, U.S. agency notes, corporate bonds and foreign currency exchange forward contracts within Level 2 of the fair value hierarchy as follows: Certificates of Deposit The Company reviews market pricing and other observable market inputs for the same or similar securities obtained from a number of industry standard data providers. In the event that a transaction is observed for the same or similar security in the marketplace, the price on that transaction reflects the market price and fair value on that day. In the absence of any observable market transactions for a particular security, the fair market value at period end would be equal to the par value. These inputs represent quoted prices for similar assets or these inputs have been derived from observable market data. Commercial Paper The Company reviews market pricing and other observable market inputs for the same or similar securities obtained from a number of industry standard data providers. In the event that a transaction is observed for the same or similar security in the marketplace, the price on that transaction reflects the market price and fair value on that day and then follows a revised accretion schedule to determine the fair market value at period end. In the absence of any observable market transactions for a particular security, the fair market value at period end is derived by accreting from the last observable market price. These inputs represent quoted prices for similar assets or these inputs have been derived from observable market data accreted mathematically to par. U.S. Agency Notes The Company reviews trading activity and pricing for its U.S. agency notes as of the measurement date. When sufficient quoted pricing for identical securities is not available, the Company uses market pricing and other observable market inputs for similar securities obtained from a number of industry standard data providers. These inputs represent quoted prices for similar assets in active markets or these inputs have been derived from observable market data. Corporate Bonds The Company reviews trading activity and pricing for each of the corporate bond securities in its portfolio as of the measurement date and determines if pricing data of sufficient frequency and volume in an active market exists in order to support Level 1 classification of these securities. If sufficient quoted pricing for identical securities is not available, the Company obtains market pricing and other observable market inputs for similar securities from a number of industry standard data providers. In instances where multiple prices exist for similar securities, these prices are used as inputs into a distribution-curve to determine the fair market value at period end. Foreign Currency Exchange Forward Contracts As discussed in Note 6, “Derivative Instruments” to the Notes to Condensed Consolidated Financial Statements, the Company mainly holds non-speculative foreign exchange forward contracts to hedge certain foreign currency exchange exposures. The Company estimates the fair values of derivatives based on quoted market prices or pricing models using current market rates. Where applicable, these models project future cash flows and discount the future amounts to a present value using market-based observable inputs including interest rate curves, credit risk, foreign exchange rates, and forward and spot prices for currencies. The following tables represent the Company’s fair value hierarchy for its assets and liabilities measured at fair value on a recurring basis (in thousands): As of March 31, 2018 As of December 30, 2017 Fair Value Measured Using Fair Value Measured Using Level 1 Level 2 Total Level 1 Level 2 Total Assets Money market funds $ 24,393 $ — $ 24,393 $ 20,371 $ — $ 20,371 Certificates of deposit — 240 240 — 240 240 Commercial paper — 46,834 46,834 — 26,912 26,912 Corporate bonds — 96,650 96,650 — 118,558 118,558 U.S. agency notes — 5,477 5,477 — 5,480 5,480 U.S. treasuries 30,916 — 30,916 35,408 — 35,408 Total assets $ 55,309 $ 149,201 $ 204,510 $ 55,779 $ 151,190 $ 206,969 Liabilities Foreign currency exchange forward contracts $ — $ (29 ) $ (29 ) $ — $ (204 ) $ (204 ) During the three months ended March 31, 2018 , there were no transfers of assets or liabilities between Level 1 and Level 2 of the fair value hierarchy. As of March 31, 2018 and December 30, 2017 , none of the Company’s existing securities were classified as Level 3 securities. The Company classifies the following assets and liabilities within Level 3 of the fair value hierarchy and applies fair value accounting on a nonrecurring basis, only if impairment is indicated: Cost-method Investment The Company estimates the fair value of its cost-method investment by using the guideline public company method and the guideline transaction method of the market approach to determine the implied total equity value on a minority interest basis. These analyses require management to make assumptions and estimates regarding industry and economic factors, future operating results and discount rates. As of December 30, 2017, the Company determined that its cost-method investment was impaired, resulting in an impairment charge of $1.9 million to adjust the carrying value to estimated fair value. See Note 5, “Cost-method Investment” to the Notes to Condensed Consolidated Financial Statements for more information. Facilities-related Charges In the fourth quarter of 2017, the Company implemented a plan to restructure its worldwide operations (the “2017 Restructuring Plan”). As a result of the plan, the Company calculated the fair value of its facilities-related charges of $7.3 million , based on estimated future discounted cash flows and unobservable inputs, which included the amount and timing of estimated sublease rental receipts that the Company could reasonably obtain over the remaining lease term and the discount rate. During the three months ended March 31, 2018, the Company revised the estimates to its facilities-related accruals. See Note 9, “Restructuring and Other Related Costs” to the Notes to Condensed Consolidated Financial Statements for more information. Cash, cash equivalents and investments were as follows (in thousands): March 31, 2018 Adjusted Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash $ 78,195 $ — $ — $ 78,195 Commercial paper 36,357 — (8 ) $ 36,349 Money market funds 24,393 — — 24,393 Corporate bonds 2,515 — — 2,515 U.S. treasuries 9,984 — — 9,984 Total cash and cash equivalents $ 151,444 $ — $ (8 ) $ 151,436 Certificates of deposit 240 — — 240 Commercial paper 10,490 — (5 ) 10,485 Corporate bonds 75,998 — (246 ) 75,752 U.S. agency notes 5,500 — (23 ) 5,477 U.S. treasuries 20,989 — (57 ) 20,932 Total short-term investments $ 113,217 $ — $ (331 ) $ 112,886 Corporate bonds 18,586 — (203 ) 18,383 Total long-term investments 18,586 — (203 ) 18,383 Total cash, cash equivalents and investments $ 283,247 $ — $ (542 ) $ 282,705 December 30, 2017 Adjusted Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash $ 87,991 $ — $ — $ 87,991 Money market funds 20,371 — — 20,371 U.S. treasuries 7,984 — (1 ) 7,983 Total cash and cash equivalents $ 116,346 $ — $ (1 ) $ 116,345 Certificates of deposit 240 — — 240 Commercial paper 26,924 — (12 ) 26,912 Corporate bonds 90,685 — (155 ) 90,530 U.S. agency notes 2,500 — (11 ) 2,489 U.S. treasuries 27,495 — (70 ) 27,425 Total short-term investments $ 147,844 $ — $ (248 ) $ 147,596 Corporate bonds 28,186 — (158 ) 28,028 U.S. agency notes 3,002 — (11 ) 2,991 Total long-term investments $ 31,188 $ — $ (169 ) $ 31,019 Total cash, cash equivalents and investments $ 295,378 $ — $ (418 ) $ 294,960 As of March 31, 2018 , the Company’s available-for-sale investments have contractual maturity terms of up to 18 months . Gross realized gains and losses on investments were insignificant in all periods. The specific identification method is used to account for gains and losses on available-for-sale investments. As of March 31, 2018 , the Company had $264.3 million of cash, cash equivalents and short-term investments, including $50.0 million of cash and cash equivalents held by its foreign subsidiaries. The Company's cash in foreign locations is used for operational and investing activities in those locations, and the Company does not currently have the need or the intent to repatriate those funds to the United States.

Cost-method Investment

Cost-method Investment	3 Months Ended
	Mar. 31, 2018
Investments, All Other Investments [Abstract]
Cost-method Investment	Cost-method Investment In 2016, the Company invested $7.0 million in a privately-held company. In addition, this investment included a customer supply agreement and warrants to purchase up to $10.0 million of additional shares of preferred stock. The warrants vest and become exercisable upon certain conditions being met. As of March 31, 2018 , and December 30, 2017 , the Company's cost-method investment balance was $5.1 million . This investment is accounted for as a cost-method investment as the Company owns less than 20% of the voting securities and does not have the ability to exercise significant influence over operating and financial policies of the entity. The Company regularly evaluates the carrying value of its cost-method investment for impairment. If the Company believes that the carrying value of the cost-basis investment is in excess of estimated fair value, the Company’s policy is to record an impairment charge in other income (expense), net, in the accompanying condensed consolidated statements of operations. During the three months ended March 31, 2018 , no impairment charges were recorded as there have not been any events or changes in circumstances that the Company believes would have a significant adverse effect on the fair value of its investment.

Derivative Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments Foreign Currency Exchange Forward Contracts The Company transacts business in various foreign currencies and has international sales, cost of sales, and expenses denominated in foreign currencies, and carries foreign-currency-denominated monetary assets and liabilities, subjecting the Company to foreign currency risk. The Company’s primary foreign currency risk management objective is to protect the U.S. dollar value of future cash flows and minimize the volatility of reported earnings. The Company utilizes foreign currency exchange forward contracts, primarily short term in nature. The Company enters into foreign currency exchange forward contracts to manage its exposure to fluctuation in foreign exchange rates that arise from its euro and British pound denominated receivables and restricted cash balances. Gains and losses on these contracts are intended to offset the impact of foreign exchange rate fluctuations on the underlying foreign currency denominated accounts receivables and restricted cash, and therefore, do not subject the Company to material balance sheet risk. The Company also enters into foreign currency exchange forward contracts to reduce the volatility of cash flows primarily related to forecasted revenues and expenses denominated in euros, British pound and Swedish kronor (“SEK”). The contracts are settled at maturity and at rates agreed to at inception of the contracts. The gains and losses on these foreign currency derivatives are recorded to the consolidated statement of operations line item, in the current period, to which the item that is being economically hedged is recorded. During the first quarter of 2018, the Company posted $0.9 million of collateral on its derivative instruments to cover potential credit risk exposure. This amount is classified as other long-term restricted cash on the accompanying condensed consolidated balance sheets. For the three months ended March 31, 2018 and April 1, 2017 , the before-tax effect of the foreign currency exchange forward contracts were losses of $0.6 million and $0.3 million , respectively. In each of these periods, the impact of the gross gains and losses were offset by foreign exchange rate fluctuations on the underlying foreign currency denominated amounts. As of March 31, 2018 , the Company did not designate foreign currency exchange forward contracts as hedges for accounting purposes and accordingly, changes in the fair value are recorded in the accompanying condensed consolidated statements of operations. These contracts were entered into with one high-quality institution and the Company consistently monitors the creditworthiness of the counterparties. The fair value of derivative instruments not designated as hedging instruments in the Company’s condensed consolidated balance sheets was as follows (in thousands): As of March 31, 2018 As of December 30, 2017 Gross Notional (1) Other Accrued Liabilities Gross Notional (1) Other Accrued Liabilities Foreign currency exchange forward contracts Related to euro denominated receivables $ 23,335 $ (29 ) $ 24,794 $ (202 ) Related to euro denominated restricted cash $ 259 — $ 252 (2 ) $ (29 ) $ (204 ) (1) Represents the face amounts of forward contracts that were outstanding as of the period noted.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill Goodwill is recorded when the purchase price of an acquisition exceeds the fair value of the net tangible and identified intangible assets acquired. The following table presents details of the Company’s goodwill during the three months ended March 31, 2018 (in thousands): Balance as of December 30, 2017 $ 195,615 Foreign currency translation adjustments (3,053 ) Balance as of March 31, 2018 $ 192,562 The gross carrying amount of goodwill may change due to the effects of foreign currency fluctuations as these assets are denominated in SEK. To date, the Company has zero accumulated impairment loss on goodwill. Intangible Assets The following tables present details of the Company’s intangible assets as of March 31, 2018 and December 30, 2017 (in thousands, except for weighted-average): March 31, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted-Average Remaining Useful Life (In Years) Intangible assets with finite lives: Customer relationships $ 50,253 $ (16,343 ) $ 33,910 5.4 Developed technology 103,072 (53,024 ) 50,048 2.5 Total intangible assets $ 153,325 $ (69,367 ) $ 83,958 3.6 December 30, 2017 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Useful Life (In Years) Intangible assets with finite lives: Customer relationships $ 51,050 $ (15,007 ) $ 36,043 5.6 Developed technology 104,708 (48,563 ) 56,145 2.7 Total intangible assets $ 155,758 $ (63,570 ) $ 92,188 3.9 The gross carrying amount of intangible assets and the related amortization expense of intangible assets may change due to the effects of foreign currency fluctuations as these assets are denominated in SEK. Amortization expense was $6.9 million for the three months ended March 31, 2018 and was $6.3 million for the corresponding period in 2017. Intangible assets are carried at cost less accumulated amortization. Amortization expenses are recorded to the appropriate cost and expense categories. During 2017, the Company recorded an impairment charge to research and development expenses of $0.3 million for certain intangible assets, which the Company has determined that the carrying value will not be recoverable. During the first quarter of 2017, the Company transferred $0.3 million of its in-process technology to developed technology, which is being amortized over a useful life of five years. The following table summarizes the Company’s estimated future amortization expense of intangible assets with finite lives as of March 31, 2018 (in thousands): Fiscal Years Total Remainder of 2018 2019 2020 2021 2022 2023 and Thereafter Total future amortization expense $ 83,958 $ 20,370 $ 26,548 $ 19,372 $ 7,082 $ 6,466 $ 4,120

Balance Sheet Details

Balance Sheet Details	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Details	Balance Sheet Details Restricted Cash The Company’s restricted cash balance is primarily comprised of certificates of deposit and money market funds, of which the majority is not insured by the Federal Deposit Insurance Corporation. These amounts primarily collateralize the Company’s issuances of standby letters of credit and bank guarantees. Additionally, our restricted cash balance includes amounts pledged as collateral on our derivative instruments. The following table provides details of selected balance sheet items (in thousands): March 31, 2018 December 30, 2017 Inventory Raw materials $ 30,303 $ 27,568 Work in process 66,499 59,662 Finished goods 119,086 127,474 Total inventory $ 215,888 $ 214,704 Property, plant and equipment, net Computer hardware $ 14,098 $ 13,881 Computer software (1) 32,791 32,521 Laboratory and manufacturing equipment 250,562 246,380 Land and building 12,347 12,347 Furniture and fixtures 2,547 2,474 Leasehold and building improvements 43,301 43,475 Construction in progress 32,598 34,816 Subtotal $ 388,244 $ 385,894 Less accumulated depreciation and amortization (253,048 ) (249,952 ) Total property, plant and equipment, net $ 135,196 $ 135,942 Accrued expenses Loss contingency related to non-cancelable purchase commitments $ 6,207 $ 6,379 Professional and other consulting fees 4,837 5,305 Taxes payable 3,864 3,707 Royalties 5,447 5,404 Restructuring accrual 4,273 5,490 Right of return 12,756 — Other accrued expenses 14,571 13,497 Total accrued expenses $ 51,955 $ 39,782 (1) Included in computer software at March 31, 2018 and December 30, 2017 were $11.4 million related to enterprise resource planning ( “ ERP ” ) systems that the Company implemented. The unamortized ERP costs at March 31, 2018 and December 30, 2017 were $4.2 million and $4.7 million , respectively.

Restructuring and Other Related

Restructuring and Other Related Costs	3 Months Ended
	Mar. 31, 2018
Restructuring and Related Activities [Abstract]
Restructuring and Other Related Costs	Restructuring and Other Related Costs In the fourth quarter of 2017, the Company implemented the 2017 Restructuring Plan in order to reduce expenses and establish a more cost-effective structure that better aligns the Company's operations with its long-term strategies. As part of the 2017 Restructuring Plan, the Company is making several changes it believes will help its research and development efficiency, with consolidation of its development sites, including closure of its Beijing, China design center, process changes to more broadly leverage the Company's engineering resources across regions and product line development, and prioritization of research and development initiatives. Outside of engineering, the Company has also made changes to allow it to operate more efficiently as it scales the business, including reducing the Company's facilities footprint and writing off certain equipment that will not be utilized in the future. Finally, the Company realigned its inventory levels to match its new technology cadence and go to market strategies. As of December 30, 2017, the 2017 Restructuring Plan had been substantially completed and we do not expect to record significant future charges under this plan in 2018. During the first quarter of 2018, the Company revised the estimates to its facilities-related and severance expenses as described further below. The following table presents restructuring and other related costs (credits) included in cost of revenue and operating expenses in the accompanying consolidated statements of operations under the 2017 Restructuring Plan (in thousands): Three Months Ended March 31, 2018 Cost of Revenue Operating Expenses Severance and related expenses $ 17 $ 945 Facilities — (1,084 ) Asset impairment — (24 ) Total $ 17 $ (163 ) Restructuring liabilities are reported within accrued expenses and other long-term liabilities in the accompanying consolidated balance sheets (in thousands): December 30, 2017 Charges (Credits) Cash Non-cash Settlements and Other March 31, 2018 Severance and related expenses $ 3,672 $ 962 $ (1,970 ) $ — $ 2,664 Facilities 6,947 (1,084 ) (268 ) (40 ) 5,555 Asset impairment — (24 ) — 24 — Total $ 10,619 $ (146 ) $ (2,238 ) $ (16 ) $ 8,219 During the first quarter of 2018, the Company revised its estimates related to its facilities closures due to the sublease of several restructured facilities and also recorded severance costs for additional impacted employees. As of March 31, 2018, the Company's restructuring liability was comprised of $5.6 million related to facility closures, with leases through January 2022, and $2.7 million of severance and related expenses, which are expected to be substantially paid during the remainder of 2018.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Accumulated Other Comprehensive Income	Accumulated Other Comprehensive Income Accumulated other comprehensive income includes certain changes in equity that are excluded from net loss. The following table sets forth the changes in accumulated other comprehensive income by component for the three months ended March 31, 2018 (in thousands): Unrealized Loss on Other Available-for-Sale Securities Foreign Currency Translation Accumulated Tax Effect Total Balance at December 30, 2017 $ (418 ) $ 7,551 $ (879 ) $ 6,254 Net current-period other comprehensive loss (125 ) (4,816 ) — (4,941 ) Balance at March 31, 2018 $ (543 ) $ 2,735 $ (879 ) $ 1,313

Basic and Diluted Net Loss Per

Basic and Diluted Net Loss Per Common Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Basic and Diluted Net Loss Per Common Share	Basic and Diluted Net Loss Per Common Share Basic net loss per common share is computed by dividing net loss attributable to Infinera Corporation by the weighted average number of common shares outstanding during the period. Diluted net loss attributable to the Company per common share is computed using net loss attributable to the Company and the weighted average number of common shares outstanding plus potentially dilutive common shares outstanding during the period. Potentially dilutive common shares include the assumed exercise of outstanding stock options, assumed release of outstanding RSUs and PSUs, and assumed issuance of common stock under the Company's Employee Stock Purchase Plan (“ESPP") using the treasury stock method. Potentially dilutive common shares also include the assumed conversion of the Notes from the conversion spread (as defined and discussed in Note 12, “Convertible Senior Notes” to the Notes to Condensed Consolidated Financial Statements). The Company includes the common shares underlying PSUs in the calculation of diluted net income per share only when they become contingently issuable. The following table sets forth the computation of net loss per common share – basic and diluted (in thousands, except per share amounts): Three Months Ended March 31, 2018 April 1, 2017 Net loss $ (26,280 ) $ (40,451 ) Weighted average common shares outstanding - basic and diluted 150,333 145,786 Net loss per common share - basic and diluted $ (0.17 ) $ (0.28 ) The Company incurred net losses during the three months ended March 31, 2018 and April 1, 2017, and as a result, potential common shares from stock options, RSUs, PSUs, assumed release of outstanding stock under the ESPP and assumed conversion of the Notes from the conversion spread were not included in the diluted shares used to calculate net loss per share, as their inclusion would have been anti-dilutive. The following sets forth the potentially dilutive shares excluded from the computation of the diluted net loss per share because their effect was anti-dilutive (in thousands): Three Months Ended March 31, 2018 April 1, 2017 Stock options 1,187 1,634 RSUs 9,439 7,773 PSUs 1,545 1,414 ESPP shares 2,247 953 Total 14,418 11,774

Convertible Senior Notes

Convertible Senior Notes	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Convertible Senior Notes	Convertible Senior Notes In May 2013, the Company issued the Notes, which will mature on June 1, 2018, unless earlier purchased by the Company or converted. The Company has made semi-annual interest payments with one payment remaining on June 1, 2018. The net proceeds to the Company were approximately $144.5 million and were intended to be used for working capital and other general corporate purposes. To date, the Company has not utilized the net proceeds due to its sufficient cash position. The Notes are governed by an indenture dated as of May 30, 2013 (the “Indenture”), between the Company, as issuer, and U.S. Bank National Association, as trustee. The Notes are unsecured and do not contain any financial covenants or any restrictions on the payment of dividends, the incurrence of senior debt or other indebtedness, or the issuance or repurchase of securities by the Company. Upon conversion, it is the Company's intention to pay cash equal to the lesser of the aggregate principal amount or the conversion value of the Notes. For any remaining conversion obligation, the Company intends to pay cash. For all conversions that occur on or after December 1, 2017, the Company has elected a cash settlement method. The current conversion rate is 79.4834 shares of common stock per $1,000 principal amount of Notes, subject to anti-dilution adjustments, which is equivalent to a conversion price of approximately $12.58 per share of common stock. Throughout the term of the Notes, the conversion rate may be adjusted upon the occurrence of certain events, including for any cash dividends. Holders of the Notes will not receive any cash payment representing accrued and unpaid interest upon conversion of a Note. Accrued but unpaid interest will be deemed to be paid in full upon conversion rather than canceled, extinguished or forfeited. Holders may convert their Notes under the following circumstances: • during any fiscal quarter (and only during such fiscal quarter) if the last reported sale price of the common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding fiscal quarter is greater than or equal to 130% of the conversion price on each applicable trading day; • during the five business day period after any five consecutive trading day period (the “measurement period”) in which the trading price per $1,000 principal amount of Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; • upon the occurrence of specified corporate events described under the Indenture, such as a consolidation, merger or binding share exchange; or • at any time on or after December 1, 2017 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their Notes at any time, regardless of the foregoing circumstances. If the Company undergoes a fundamental change as defined in the Indenture governing the Notes, holders may require the Company to repurchase for cash all or any portion of their Notes at a repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date. In addition, upon the occurrence of a “make-whole fundamental change” (as defined in the Indenture), the Company may, in certain circumstances, increase the conversion rate by a number of additional shares for a holder that elects to convert its Notes in connection with such make-whole fundamental change. The net carrying amounts of the debt obligation were as follows (in thousands): March 31, 2018 December 30, 2017 Principal $ 150,000 $ 150,000 Unamortized discount (1) (1,891 ) (4,670 ) Unamortized issuance cost (1) (163 ) (402 ) Net carrying amount $ 147,946 $ 144,928 (1) Unamortized debt conversion discount and issuance costs will be amortized over the remaining life of the Notes, which is approximately 2 months from March 31, 2018. As of March 31, 2018 and December 30, 2017 , the carrying amount of the equity component of the Notes was $43.3 million . In accounting for the issuance of the Notes, the Company separated the Notes into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar debt instrument that does not have an associated convertible feature. The carrying amount of the equity component representing the conversion option was determined by deducting the fair value of the liability component from the par value of the Notes. The equity component is not remeasured as long as it continues to meet the conditions for equity classification. The excess of the principal amount of the liability component over its carrying amount (“debt discount”) is amortized to interest expense over the term of the Notes. In accounting for the issuance costs of $5.5 million related to the Notes, the Company allocated the total amount incurred to the liability and equity components of the Notes based on their relative values. Issuance costs attributable to the liability component were initially recorded as other non-current assets and were amortized to interest expense over the term of the Notes. Accounting Standards Update 2015-03, “Simplifying the Presentation of Debt Issuance Costs” (“ASU 2015-03”) requires an entity to present such costs in the balance sheet as a direct deduction from the related debt liability rather than as an asset. The Company adopted ASU 2015-03 during the first quarter of 2016. The December 31, 2016 balance sheet was retrospectively adjusted to reclassify $2.1 million from other non-current assets to a reduction of the Notes payable liability. The issuance costs attributable to the equity component were netted with the equity component in stockholders’ equity. Additionally, the Company initially recorded a deferred tax liability of $17.0 million in connection with the issuance of the Notes, and a corresponding reduction in valuation allowance. The impact of both was recorded to stockholders’ equity. The Company determined that the embedded conversion option in the Notes does not require separate accounting treatment as a derivative instrument because it is both indexed to the Company’s own stock and would be classified in stockholder’s equity if freestanding. The following table sets forth total interest expense recognized related to the Notes (in thousands): Three Months Ended March 31, 2018 April 1, 2017 Contractual interest expense $ 656 $ 656 Amortization of debt issuance costs 239 216 Amortization of debt discount 2,779 2,514 Total interest expense $ 3,674 $ 3,386 The coupon rate is 1.75% . For the three months ended March 31, 2018 and April 1, 2017 , the debt discount and debt issuance costs were amortized, using an annual effective interest rate of 10.23% , to interest expense over the term of the Notes. As of March 31, 2018 , the fair value of the Notes was $151.1 million . The fair value was determined based on the quoted bid price of the Notes in an over-the-counter market on March 29, 2018. The Notes are classified as Level 2 of the fair value hierarchy. The Notes became convertible at the option of the holders on December 1, 2017 and will be convertible until the close of business on the second scheduled trading day immediately preceding the maturity date. Based on the closing price of the Company’s common stock of $10.86 on March 29, 2018 (the last trading day of the fiscal quarter), the if-converted value of the Notes did not exceed their principal amount.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stockholders' Equity	Stockholders’ Equity Stock-based Compensation Plans The Company has stock-based compensation plans pursuant to which the Company has granted stock options, RSUs and PSUs. The Company also has an ESPP for all eligible employees. In February 2016, the Company's board of directors adopted the 2016 Equity Incentive Plan (“2016 Plan”) and the Company's stockholders approved the 2016 Plan in May 2016. In May 2017, the Company's stockholders approved an amendment to the 2016 Plan to increase the number of shares authorized for issuance under the 2016 Plan by 6.4 million shares. As of March 31, 2018 , the Company has reserved a total of 13.9 million shares of common stock for issuance of stock options, RSUs and PSUs to employees, non-employees, consultants and members of the Company's board of directors, pursuant to the 2016 Plan, plus any shares subject to awards granted under the Company’s 2007 Equity Incentive Plan (the “2007 Plan”) that, after the effective date of the 2016 Plan, expire, are forfeited or otherwise terminate without having been exercised in full to the extent such awards were exercisable, and shares issued pursuant to awards granted under the 2007 Plan that, after the effective date of the 2016 Plan, are forfeited to or repurchased by the Company due to failure to vest. The 2016 Plan has a maximum term of 10 years from the date of adoption, or it can be earlier terminated by the Company's board of directors. The 2007 Plan was canceled; however, it continues to govern outstanding grants under the 2007 Plan. The following tables summarize the Company’s equity award activity and related information (in thousands, except per share data): Number of Stock Options Weighted-Average Exercise Price Per Share Aggregate Intrinsic Value Outstanding at December 30, 2017 1,397 $ 8.11 $ 1 Stock options granted — $ — Stock options exercised (162 ) $ 7.79 $ 340 Stock options canceled (48 ) $ 11.47 Outstanding at March 31, 2018 1,187 $ 8.02 $ 3,380 Exercisable at March 31, 2018 1,187 $ 8.02 $ 3,380 Number of Restricted Stock Units Weighted- Average Grant Date Fair Value Per Share Aggregate Intrinsic Value Outstanding at December 30, 2017 6,791 $ 11.55 $ 42,988 RSUs granted 3,151 $ 11.01 RSUs released (264 ) $ 11.78 $ 2,065 RSUs canceled (239 ) $ 11.18 Outstanding at March 31, 2018 9,439 $ 11.37 $ 102,510 Number of Performance Stock Units Weighted- Average Grant Date Fair Value Per Share Aggregate Intrinsic Value Outstanding at December 30, 2017 1,367 $ 16.28 $ 8,651 PSUs granted 505 $ 15.87 PSUs released — $ — $ — PSUs canceled (327 ) $ 15.75 Outstanding at March 31, 2018 1,545 $ 16.25 $ 16,771 Expected to vest at March 31, 2018 1,098 $ 11,928 The aggregate intrinsic value of unexercised stock options is calculated as the difference between the closing price of the Company’s common stock of $10.86 at March 29, 2018 (the last trading day of the fiscal quarter) and the exercise prices of the underlying stock options. The aggregate intrinsic value of the stock options that have been exercised is calculated as the difference between the fair market value of the common stock at the date of exercise and the exercise price of the underlying stock options. The aggregate intrinsic value of unreleased RSUs and unreleased PSUs is calculated using the closing price of the Company's common stock of $10.86 at March 29, 2018 (the last trading day of the fiscal quarter). The aggregate intrinsic value of RSUs and PSUs released is calculated using the fair market value of the common stock at the date of release. The following table presents total stock-based compensation cost for instruments granted but not yet amortized, net of estimated forfeitures, of the Company’s equity compensation plans as of March 31, 2018 . These costs are expected to be amortized on a straight-line basis over the following weighted-average periods (in thousands, except for weighted-average period): Unrecognized Compensation Expense, Net Weighted- Average Period (in years) RSUs $ 80,840 3.0 PSUs $ 14,328 1.8 Employee Stock Options The Company did not grant any stock options during the three months ended March 31, 2018 . Amortization of stock-based compensation related to stock options in the three months ended March 31, 2018 was insignificant. Employee Stock Purchase Plan The fair value of the shares was estimated at the date of grant using the following assumptions (expense amounts in thousands): Three Months Ended Employee Stock Purchase Plan March 31, 2018 April 1, 2017 Volatility 62% 51% Risk-free interest rate 1.90% 0.81% Expected life 0.5 years 0.5 years Estimated fair value $3.13 $3.46 Total stock-based compensation expense $1,555 $1,681 Restricted Stock Units During the three months ended March 31, 2018 , the Company granted RSUs to employees to receive 3.2 million shares of the Company’s common stock. All RSUs awarded are subject to each individual's continued service to the Company through each applicable vesting date. The Company accounted for the fair value of the RSUs using the closing market price of the Company’s common stock on the date of grant. Amortization of stock-based compensation related to RSUs in the three months ended March 31, 2018 and April 1, 2017 was approximately $7.4 million and $7.7 million , respectively. Performance Stock Units Pursuant to the 2007 Plan and the 2016 Plan, the Company has granted PSUs to certain of the Company’s executive officers, senior management and other employees. All PSUs awarded are subject to each individual's continued service to the Company through each applicable vesting date and if the performance metrics are not met within the time limits specified in the award agreements, the PSUs will be canceled. PSUs granted to the Company’s executive officers and senior management under the 2007 Plan during the first quarter of 2015 and 2016 are based on the total stockholder return (“TSR”) of the Company's common stock price as compared to the TSR of the S&P North American Technology Multimedia Networking Index (“SPGIIPTR”) over the span of one year , two years and three years . The number of shares to be issued upon vesting of these PSUs range from zero to two times the target number of PSUs granted depending on the Company’s performance against the SPGIIPTR. PSUs granted to the Company’s executive officers and senior management under the 2016 Plan during the first quarter of 2018 are based on the TSR of the Company's common stock price relative to the TSR of the individual companies listed in the SPGIIPTR over the span of one year, two years and three years. The number of shares to be issued upon vesting of these PSUs range from zero to two times the target number of PSUs granted depending on the Company’s performance against the individual companies listed in the SPGIIPTR. The ranges of estimated values of the PSUs granted that are compared to the index, as well as the assumptions used in calculating these values were based on estimates as follows: 2018 2017 2016 Index SPGIIPTR SPGIIPTR SPGIIPTR Index volatility 33% 33% - 34% 18% Infinera volatility 58% - 59% 55% - 56% 55% Risk-free interest rate 2.37% - 2.40% 1.41% - 1.63% 0.95% - 1.07% Correlation with index/index component 0.04 - 0.48 0.10 - 0.49 0.58 - 0.59 Estimated fair value $14.99 - $19.46 $15.23 - $17.35 $10.31 - $16.62 In addition, certain other PSUs granted to the Company’s executive officers, senior management and certain other employees will only vest upon the achievement of specific financial or operational performance criteria. The following table summarizes by grant year, the Company’s PSU activity for the three months ended March 31, 2018 (in thousands): Grant Year Total Number of Performance Stock Units 2015 2016 2017 2018 Outstanding at December 30, 2017 1,367 77 420 869 — PSUs granted 505 — — — 505 PSUs released — — — — — PSUs canceled (327 ) (77 ) (189 ) (61 ) — Outstanding at March 31, 2018 1,545 — 231 808 505 Amortization of stock-based compensation related to PSUs in the three months ended March 31, 2018 and April 1, 2017 was approximately $2.1 million and $1.8 million , respectively. Stock-Based Compensation The following tables summarize the effects of stock-based compensation on the Company’s condensed consolidated balance sheets and statements of operations for the periods presented (in thousands): March 31, 2018 December 30, 2017 Stock-based compensation effects in inventory $ 5,383 $ 5,255 Three Months Ended March 31, 2018 April 1, 2017 Stock-based compensation effects included in net loss before income taxes Cost of revenue $ (122 ) $ 724 Research and development 4,324 3,780 Sales and marketing 2,898 2,726 General and administration 2,767 2,540 $ 9,867 $ 9,770 Cost of revenue – amortization from balance sheet (1) 1,116 1,107 Total stock-based compensation expense $ 10,983 $ 10,877 (1) Stock-based compensation expense deferred to inventory and deferred inventory costs in prior periods and recognized in the current period.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income taxes for the three months ended March 31, 2018 were a benefit of $0.7 million on a pre-tax loss of $27.0 million . This compared to a tax benefit of $0.2 million on a pre-tax loss of $40.6 million for the three months ended April 1, 2017. Provision for income taxes decreased by approximately $0.5 million during the three months ended March 31, 2018 compared to the corresponding period in 2017, as a result of an operating loss in the United States, lower foreign income tax for the Company's Swedish operations and release of tax reserves due to statute of limitations expiration. Due to the Company’s current operating losses and tax loss carryforwards in the United States and cost-plus international structures outside of Sweden, the tax expense or benefit is less sensitive to pretax income or loss than would otherwise be expected, compared to the statutory tax rate. In all periods, the tax expense and benefit projected in the Company's effective tax rate assumptions primarily represents foreign taxes of the Company's overseas subsidiaries compensated on a cost-plus basis, as well as the results of the Company's Swedish operations, inclusive of purchase accounting amortization and other charges for the three months ended March 31, 2018. The Company must assess the likelihood that some portion or all of its deferred tax assets will be recovered from future taxable income within the respective jurisdictions. In the past, the Company established a valuation allowance against its deferred tax assets as it determined that its ability to recover the value of these assets did not meet the “more-likely-than-not” standard. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management judgment is required on an on-going basis to determine whether it needs to maintain the valuation allowance recorded against its net deferred tax assets. The Company must consider all positive and negative evidence, including its forecasts of taxable income over the applicable carryforward periods, its current financial performance, its market environment and other factors in evaluating the need for a valuation allowance against its net U.S. deferred tax assets. At March 31, 2018, the Company does not believe that it is more-likely-than-not that it would be able to utilize its domestic deferred tax assets in the foreseeable future. Accordingly, the domestic net deferred tax assets continued to be fully reserved with a valuation allowance. To the extent that the Company determines that deferred tax assets are realizable on a more-likely-than-not basis, and adjustment is needed, that adjustment will be recorded in the period that the determination is made and would generally decrease the valuation allowance and record a corresponding benefit to earnings. The Company reasonably estimated the impact of the Tax Act on its income tax provision for the year ended December 30, 2017, based on its understanding of the Tax Act and guidance at that time. The estimates are subject to adjustment during a measurement period not to extend beyond one year from the enactment date of the Tax Act, or by December 22, 2018. During the three months ended March 31, 2018, no adjustments to prior year estimates were made. Adjustments may be made during the measurement period subject to refinement of the Company's analysis and further technical guidance.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Information	Segment Information Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision maker, or decision making group, in deciding how to allocate resources and in assessing performance. The Company’s chief operating decision maker is the Company’s Chief Executive Officer (“CEO”). The Company’s CEO reviews financial information presented on a consolidated basis, accompanied by information about revenue by geographic region for purposes of allocating resources and evaluating financial performance. The Company has one business activity as a provider of optical transport networking equipment, software and services. Accordingly, the Company is considered to be in a single reporting segment and operating unit structure. The following table sets forth long-lived assets by geographic region (in thousands): March 31, 2018 December 30, 2017 United States $ 127,851 $ 128,582 Other Americas 1,323 661 Europe, Middle East and Africa 3,310 3,527 Asia Pacific 2,712 3,172 Total property, plant and equipment, net $ 135,196 $ 135,942 For information regarding revenue disaggregated by geography, see Note 3, “Revenue Recognition” to the Notes to Condensed Consolidated Financial Statements.

Guarantees

Guarantees	3 Months Ended
	Mar. 31, 2018
Guarantees [Abstract]
Guarantees	Guarantees Product Warranties Activity related to product warranty was as follows (in thousands): Three Months Ended March 31, 2018 April 1, 2017 Beginning balance $ 30,909 $ 40,342 Charges to operations 4,357 4,659 Utilization (4,438 ) (3,388 ) Change in estimate (1) 20 (5,633 ) Balance at the end of the period $ 30,848 $ 35,980 (1) The Company records product warranty liabilities based on the latest quality and cost information available as of the date the revenue is recorded. The changes in estimate shown here are due to changes in overall actual failure rates, the mix of new versus used units related to replacement of failed units, and changes in the estimated cost of repair. As the Company's products mature over time, failure rates and repair costs generally decline leading to favorable changes in warranty reserves. In addition, during the first quarter of 2017, due to product quality improvements, the Company revised certain estimates used in calculating its product warranties that resulted in a one-time reduction to the warranty accrual of $2.2 million . Letters of Credit and Bank Guarantees The Company had $3.7 million of standby letters of credit and bank guarantees outstanding as of March 31, 2018 that consisted of $1.7 million related to customer performance guarantees, $1.3 million related to value added tax and customs' licenses, and $0.7 million related to property leases. The Company had $4.2 million of standby letters of credit and bank guarantees outstanding as of December 30, 2017 that consisted of $2.2 million related to customer performance guarantees and $1.3 million related to a value added tax license and $0.7 million related to property leases. As of March 31, 2018 and December 30, 2017 , the Company had a line of credit for approximately $1.6 million and $1.6 million , respectively, to support the issuance of letters of credit, of which zero and zero had been issued and outstanding, respectively. The Company has pledged approximately $5.3 million and $5.2 million of assets of a subsidiary to secure this line of credit and other obligations as of March 31, 2018 and December 30, 2017 , respectively.

Litigation and Contingencies

Litigation and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Litigation and Contingencies	Litigation and Contingencies Legal Matters On November 23, 2016, Oyster Optics, LLC (“Oyster Optics”) filed a complaint against the Company in the United States District Court for the Eastern District of Texas. The complaint asserts U.S. Patent Nos. 6,469,816, 6,476,952, 6,594,055, 7,099,592, 7,620,327, 8,374,511 and 8,913,898 (collectively, the “Oyster Optics patents in suit”). The complaint seeks unspecified damages and a permanent injunction. The Company believes that it does not infringe any valid and enforceable claim of the Oyster Optics patents in suit and intends to defend this action vigorously. The Company filed its answer to Oyster Optics' complaint on February 3, 2017. On October 23, 2017, the Company filed a petition for Inter Partes Review (“IPR”) of one of the Oyster Optics patents in suit, U.S. Patent No. 8,913,898 with the U.S. Patent and Trademark Office. Other defendants have filed IPR petitions in connection with the Oyster Optics patents in suit. A Markman decision issued on December 5, 2017 and fact discovery closed on December 22, 2017. Oyster Optics has now dropped all the Oyster Optics patents in suit, except for a few claims in U.S. Patent No. 7,620,327. A pre-trial conference is scheduled for May 29, 2018. The Court has set a trial date for June 2018. The Company is currently unable to predict the outcome of this litigation and therefore cannot reasonably estimate the possible loss or range of loss, if any, arising from this matter. On March 24, 2017, Core Optical Technologies, LLC (“Core Optical”) filed a complaint against the Company in the United States District Court for the Central District of California. The complaint asserts U.S. Patent No. 6,782,211 (the “Core Optical patent in suit”). The complaint seeks unspecified damages and a permanent injunction. The Company believes that it does not infringe any valid and enforceable claim of the Core Optical patent in suit and intends to defend this action vigorously. The Company filed its answer to Core Optical's complaint on September 25, 2017. A Markman hearing was scheduled for May 9, 2018. The Court has set a trial for March 2019. The Company is unable to predict the outcome of this litigation at this time and therefore cannot reasonably estimate the possible loss or range of loss, if any, arising from this matter. In addition to the matters described above, the Company is subject to various legal proceedings, claims and litigation arising in the ordinary course of business. While the outcome of these matters is currently not determinable, the Company does not expect that the ultimate costs to resolve these matters will have a material effect on its consolidated financial position, results of operations or cash flows. Loss Contingencies The Company is subject to the possibility of various losses arising in the ordinary course of business. These may relate to disputes, litigation and other legal actions. In the preparation of its quarterly and annual financial statements, the Company considers the likelihood of loss or the incurrence of a liability, including whether it is probable, reasonably possible or remote that a liability has been incurred, as well as the Company’s ability to reasonably estimate the amount of loss, in determining loss contingencies. In accordance with U.S. GAAP, an estimated loss contingency is accrued when it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. The Company regularly evaluates current information to determine whether any accruals should be adjusted and whether new accruals are required. As of March 31, 2018, the Company has accrued the estimated liabilities associated with certain loss contingencies. Indemnification Obligations From time to time, the Company enters into certain types of contracts that contingently require it to indemnify parties against third party claims. The terms of such indemnification obligations vary. These contracts may relate to: (i) certain real estate leases under which the Company may be required to indemnify property owners for environmental and other liabilities, and other claims arising from the Company’s use of the applicable premises; (ii) contracts with certain customers, which require the Company to indemnify them as further described below; and (iii) certain agreements with the Company’s officers, directors and certain key employees, under which the Company may be required to indemnify such persons for liabilities as further described below. In addition, the Company has agreed to indemnify certain customers for claims made against the Company’s products, where such claims allege infringement of third party intellectual property rights, including, but not limited to, patents, registered trademarks, and/or copyrights. Under the aforementioned intellectual property indemnification clauses, the Company may be obligated to defend the customer and pay for the damages awarded against the customer under an infringement claim as well as the customer’s attorneys’ fees and costs. These indemnification obligations generally do not expire after termination or expiration of the agreement containing the indemnification obligation. In certain cases, there are limits on and exceptions to the Company’s potential liability for indemnification. Although historically, the Company has not made significant payments under these indemnification obligations, the Company cannot estimate the amount of potential future payments, if any, that it might be required to make as a result of these agreements. The maximum potential amount of any future payments that the Company could be required to make under these indemnification obligations could be significant. As permitted under Delaware law and the Company’s charter and bylaws, the Company has agreements whereby it indemnifies certain of its officers and each of its directors. The term of the indemnification period is for the officer’s or director’s lifetime for certain events or occurrences while the officer or director is, or was, serving at the Company’s request in such capacity. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements could be significant; however, the Company has a director and officer insurance policy that may reduce its exposure and enable it to recover all or a portion of any future amounts paid. As a result of its insurance policy coverage, the Company believes the estimated fair value of these indemnification agreements is minimal.

Recent Accounting Pronounceme24

Recent Accounting Pronouncements (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting Pronouncements Recently Adopted In December 2017, the SEC staff issued Staff Accounting Bulletin No. 118, “Income Tax Accounting Implications of the Tax Cuts and Jobs Act" (“SAB 118”), which allows the Company to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. Since the U.S. Tax Cuts and Jobs Act (the “Tax Act”) was passed in December 2017, and ongoing guidance and accounting interpretation are expected over the next 12 months, the Company considers the accounting of the transition tax and deferred tax re-measurements to be incomplete due to the forthcoming guidance and the ongoing analysis of final year-end data and tax positions. The Company expects to complete the analysis within the measurement period in accordance with SAB 118. In March 2018, the Financial Accounting Standards Board (the “FASB”) issued ASU 2018-05, Amendments to SEC Paragraphs Pursuant to SAB 118 and added such SEC guidance to Accounting Standards Codification 740, “Income Taxes, codified under the title: Income Tax Accounting Implications of the Tax Cuts and Jobs Act.” In May 2017, the FASB issued Accounting Standards Update 2017-09, “Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting” (“ASU 2017-09”), which amends the scope of modification accounting for share-based payment arrangements, and provides guidance on the types of changes to the terms or conditions of share-based payment awards to which an entity would be required to apply modification accounting under Topic 718. The Company's adoption of ASU 2017-09 during its first quarter of 2018 had no impact on its condensed consolidated financial statements. In November 2016, the FASB issued ASU 2016-18, which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents and amounts generally described as restricted cash or restricted cash equivalents. As such, restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and ending-of-period total amounts shown on the statement of cash flows. The Company adopted ASU 2016-18 during the first quarter of fiscal 2018, using the retrospective transition approach. See the condensed consolidated statements of cash flows for a reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets that sum to the total of the same such amounts on the condensed consolidated statements of cash flows. In May 2016, the FASB issued Accounting Standards Update 2016-11, “Revenue Recognition (Topic 605) and Derivatives and Hedging (Topic 815): Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09 and 2014-16 Pursuant to Staff Announcements at the March 3, 2016 EITF Meeting (SEC Update)” (“ASU 2016-11”), which rescinds various standards codified as part of Topic 605, Revenue Recognition in relation to the future adoption of Topic 606. These rescissions include changes to topics pertaining to revenue and expense recognition for freight services in process, accounting for shipping and handling fees and costs, and accounting for consideration given by a vendor to a customer. The Company adopted ASU 2016-11 during the first quarter of 2018. See Note 3, “Revenue Recognition” to the Notes to Condensed Consolidated Financial Statements for more information. In May 2014, the FASB issued ASC 606, which creates a single, joint revenue standard that is consistent across all industries and markets for companies that prepare their financial statements in accordance with U.S. GAAP. Under ASC 606, an entity is required to recognize revenue upon the transfer of promised goods or services to customers in an amount that reflects the consideration the entity expects to be entitled to receive in exchange for those goods or services. In August 2015, the FASB issued Accounting Standards update 2015-14, “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date,” which deferred the effective date of ASC 606 by one year with early adoption permitted beginning after December 15, 2016. The updated standard is effective for interim and annual periods beginning after December 15, 2017. In April 2016, the FASB issued Accounting Standards Update 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing,” which clarifies the implementation guidance on identifying performance obligations and licensing. In May 2016, the FASB issued Accounting Standards Update 2016-12, “Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients,” which amends the guidance on collectability, noncash consideration, presentation of sales tax and transition. In December 2016, the FASB issued Accounting Standards Update 2016-20, “Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers,” to increase stakeholders' awareness of the proposals and to expedite improvements to ASC 606. ASC 606 also includes Subtopic 340-40, “Other Assets and Deferred Costs - Contracts with Customers,” which requires the deferral of incremental costs of obtaining a contract with a customer. Collectively, the Company refers to ASC 606 and Subtopic 340-40 as “ASC 606.” The Company adopted ASC 606 as of December 31, 2017 using the modified retrospective transition method applied to those contracts that were not completed as of December 31, 2017. See Note 3, “Revenue Recognition” to the Notes to Condensed Consolidated Financial Statements for more information. Accounting Pronouncements Not Yet Effective In January 2017, the FASB issued Accounting Standards Update 2017-04, “Simplifying the Test for Goodwill Impairment” (“ASU 2017-04”). The guidance eliminates Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. A goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The same one-step impairment test will be applied to goodwill at all reporting units, even those with zero or negative carrying amounts. Entities will be required to disclose the amount of goodwill at reporting units with zero or negative carrying amounts. ASU 2017-04 will be effective for the Company's annual or any interim goodwill impairment tests in its first quarter of fiscal 2020. The Company is currently evaluating the impact the adoption of ASU 2017-04 will have on its consolidated financial statements. In June 2016, the FASB issued Accounting Standards Update 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”), which requires measurement and recognition of expected credit losses for financial assets held. This guidance is effective for the Company in its first quarter of fiscal 2020 and early adoption is permitted. The Company is currently evaluating the impact the adoption of ASU 2016-13 will have on its consolidated financial statements. In February 2016, the FASB issued Accounting Standards Update 2016-02, “Leases (Topic 842)” (“ASU 2016-02”), which amends the existing accounting standards for leases. The new standard requires lessees to record a right-of-use asset and a corresponding lease liability on the balance sheet (with the exception of short-term leases). For lessees, leases will continue to be classified as either operating or financing in the income statement. This guidance is effective for the Company in its first quarter of fiscal 2019 and early adoption is permitted. ASU 2016-02 is required to be applied with a modified retrospective approach and requires application of the new standard at the beginning of the earliest comparative period presented. The Company is currently evaluating the impact the adoption of ASU 2016-02 will have on its consolidated financial statements and expects to have increases in the assets and liabilities of its consolidated balance sheets.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table presents the Company's revenue disaggregated by revenue source (in thousands): Three Months Ended March 31, 2018 April 1, 2017 (1) Product $ 171,629 $ 147,053 Services 31,052 28,469 Total revenue $ 202,681 $ 175,522 The following tables present the Company's revenue disaggregated by geography, based on the shipping address of the customer, and by customer channel (in thousands): Three Months Ended March 31, 2018 April 1, 2017 (1) United States $ 129,025 $ 99,780 Other Americas 5,215 6,035 Europe, Middle East and Africa 59,199 57,413 Asia Pacific 9,242 12,294 Total revenue $ 202,681 $ 175,522 Three Months Ended March 31, 2018 April 1, 2017 (1) Direct $ 188,462 $ 165,946 Indirect 14,219 9,576 Total revenue $ 202,681 $ 175,522 (1) Prior period amounts have not been adjusted under the modified retrospective method.
Contract with Customer, Asset and Liability	The following table provides information about receivables, contract assets and contract liabilities from contracts with customers (in thousands): March 31, 2018 At Adoption Accounts receivable, net $ 161,541 $ 135,245 Contract assets $ 2,670 $ 2,825 Deferred revenue $ 71,641 $ 75,458
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction	The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied (or partially satisfied) at the end of the reporting period (in thousands): Remainder of 2018 2019 2020 2021 2022 Thereafter Total Revenue expected to be recognized in the future as of March 31, 2018 $ 167,860 $ 16,382 $ 13,040 $ 2,716 $ 1,972 $ 1,876 $ 203,846
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	The following tables summarize the impacts of adopting ASC 606 on the Company's condensed consolidated statement of operations for the three months ended March 31, 2018 and the Company's condensed consolidated balance sheet as of December 31, 2017 (in thousands): Three Months Ended March 31, 2018 As Reported Adjustments Balances Without Adoption of ASC 606 Income Statement Revenue Product $ 171,629 $ 1,944 $ 173,573 Services 31,052 1,282 32,334 $ 202,681 $ 3,226 $ 205,907 Costs and expenses Cost of revenue $ 120,513 $ 528 $ 121,041 Net loss $ (26,280 ) $ 2,698 $ (23,582 ) Balance at December 30, 2017 Adjustments due to ASC 606 As Adjusted Balance at December 31, 2017 Balance Sheet Assets Accounts receivable, net $ 126,152 $ 9,093 $ 135,245 Inventory $ 214,704 $ (239 ) $ 214,465 Prepaid expenses and other assets $ 43,339 $ 2,731 $ 46,070 Liabilities Accrued expenses $ 39,782 $ 15,645 $ 55,427 Deferred revenue $ 94,923 $ (19,465 ) $ 75,458 Equity Accumulated deficit $ (758,081 ) $ 15,406 $ (742,675 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables represent the Company’s fair value hierarchy for its assets and liabilities measured at fair value on a recurring basis (in thousands): As of March 31, 2018 As of December 30, 2017 Fair Value Measured Using Fair Value Measured Using Level 1 Level 2 Total Level 1 Level 2 Total Assets Money market funds $ 24,393 $ — $ 24,393 $ 20,371 $ — $ 20,371 Certificates of deposit — 240 240 — 240 240 Commercial paper — 46,834 46,834 — 26,912 26,912 Corporate bonds — 96,650 96,650 — 118,558 118,558 U.S. agency notes — 5,477 5,477 — 5,480 5,480 U.S. treasuries 30,916 — 30,916 35,408 — 35,408 Total assets $ 55,309 $ 149,201 $ 204,510 $ 55,779 $ 151,190 $ 206,969 Liabilities Foreign currency exchange forward contracts $ — $ (29 ) $ (29 ) $ — $ (204 ) $ (204 )
Investments at Fair Value	Cash, cash equivalents and investments were as follows (in thousands): March 31, 2018 Adjusted Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash $ 78,195 $ — $ — $ 78,195 Commercial paper 36,357 — (8 ) $ 36,349 Money market funds 24,393 — — 24,393 Corporate bonds 2,515 — — 2,515 U.S. treasuries 9,984 — — 9,984 Total cash and cash equivalents $ 151,444 $ — $ (8 ) $ 151,436 Certificates of deposit 240 — — 240 Commercial paper 10,490 — (5 ) 10,485 Corporate bonds 75,998 — (246 ) 75,752 U.S. agency notes 5,500 — (23 ) 5,477 U.S. treasuries 20,989 — (57 ) 20,932 Total short-term investments $ 113,217 $ — $ (331 ) $ 112,886 Corporate bonds 18,586 — (203 ) 18,383 Total long-term investments 18,586 — (203 ) 18,383 Total cash, cash equivalents and investments $ 283,247 $ — $ (542 ) $ 282,705 December 30, 2017 Adjusted Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash $ 87,991 $ — $ — $ 87,991 Money market funds 20,371 — — 20,371 U.S. treasuries 7,984 — (1 ) 7,983 Total cash and cash equivalents $ 116,346 $ — $ (1 ) $ 116,345 Certificates of deposit 240 — — 240 Commercial paper 26,924 — (12 ) 26,912 Corporate bonds 90,685 — (155 ) 90,530 U.S. agency notes 2,500 — (11 ) 2,489 U.S. treasuries 27,495 — (70 ) 27,425 Total short-term investments $ 147,844 $ — $ (248 ) $ 147,596 Corporate bonds 28,186 — (158 ) 28,028 U.S. agency notes 3,002 — (11 ) 2,991 Total long-term investments $ 31,188 $ — $ (169 ) $ 31,019 Total cash, cash equivalents and investments $ 295,378 $ — $ (418 ) $ 294,960

Derivative Instruments (Tables)

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivative Instruments not Designated as Hedging Instruments	The fair value of derivative instruments not designated as hedging instruments in the Company’s condensed consolidated balance sheets was as follows (in thousands): As of March 31, 2018 As of December 30, 2017 Gross Notional (1) Other Accrued Liabilities Gross Notional (1) Other Accrued Liabilities Foreign currency exchange forward contracts Related to euro denominated receivables $ 23,335 $ (29 ) $ 24,794 $ (202 ) Related to euro denominated restricted cash $ 259 — $ 252 (2 ) $ (29 ) $ (204 ) (1) Represents the face amounts of forward contracts that were outstanding as of the period noted.

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table presents details of the Company’s goodwill during the three months ended March 31, 2018 (in thousands): Balance as of December 30, 2017 $ 195,615 Foreign currency translation adjustments (3,053 ) Balance as of March 31, 2018 $ 192,562
Schedule of Finite-Lived Intangible Assets	The following tables present details of the Company’s intangible assets as of March 31, 2018 and December 30, 2017 (in thousands, except for weighted-average): March 31, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted-Average Remaining Useful Life (In Years) Intangible assets with finite lives: Customer relationships $ 50,253 $ (16,343 ) $ 33,910 5.4 Developed technology 103,072 (53,024 ) 50,048 2.5 Total intangible assets $ 153,325 $ (69,367 ) $ 83,958 3.6 December 30, 2017 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Useful Life (In Years) Intangible assets with finite lives: Customer relationships $ 51,050 $ (15,007 ) $ 36,043 5.6 Developed technology 104,708 (48,563 ) 56,145 2.7 Total intangible assets $ 155,758 $ (63,570 ) $ 92,188 3.9
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The following table summarizes the Company’s estimated future amortization expense of intangible assets with finite lives as of March 31, 2018 (in thousands): Fiscal Years Total Remainder of 2018 2019 2020 2021 2022 2023 and Thereafter Total future amortization expense $ 83,958 $ 20,370 $ 26,548 $ 19,372 $ 7,082 $ 6,466 $ 4,120

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Details of Selected Balance Sheet Items	The following table provides details of selected balance sheet items (in thousands): March 31, 2018 December 30, 2017 Inventory Raw materials $ 30,303 $ 27,568 Work in process 66,499 59,662 Finished goods 119,086 127,474 Total inventory $ 215,888 $ 214,704 Property, plant and equipment, net Computer hardware $ 14,098 $ 13,881 Computer software (1) 32,791 32,521 Laboratory and manufacturing equipment 250,562 246,380 Land and building 12,347 12,347 Furniture and fixtures 2,547 2,474 Leasehold and building improvements 43,301 43,475 Construction in progress 32,598 34,816 Subtotal $ 388,244 $ 385,894 Less accumulated depreciation and amortization (253,048 ) (249,952 ) Total property, plant and equipment, net $ 135,196 $ 135,942 Accrued expenses Loss contingency related to non-cancelable purchase commitments $ 6,207 $ 6,379 Professional and other consulting fees 4,837 5,305 Taxes payable 3,864 3,707 Royalties 5,447 5,404 Restructuring accrual 4,273 5,490 Right of return 12,756 — Other accrued expenses 14,571 13,497 Total accrued expenses $ 51,955 $ 39,782 (1) Included in computer software at March 31, 2018 and December 30, 2017 were $11.4 million related to enterprise resource planning ( “ ERP ” ) systems that the Company implemented. The unamortized ERP costs at March 31, 2018 and December 30, 2017 were $4.2 million and $4.7 million , respectively.

Restructuring and Other Relat30

Restructuring and Other Related Costs (Tables)	3 Months Ended
	Mar. 31, 2018
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	The following table presents restructuring and other related costs (credits) included in cost of revenue and operating expenses in the accompanying consolidated statements of operations under the 2017 Restructuring Plan (in thousands): Three Months Ended March 31, 2018 Cost of Revenue Operating Expenses Severance and related expenses $ 17 $ 945 Facilities — (1,084 ) Asset impairment — (24 ) Total $ 17 $ (163 )
Schedule of Restructuring Reserve by Type of Cost	Restructuring liabilities are reported within accrued expenses and other long-term liabilities in the accompanying consolidated balance sheets (in thousands): December 30, 2017 Charges (Credits) Cash Non-cash Settlements and Other March 31, 2018 Severance and related expenses $ 3,672 $ 962 $ (1,970 ) $ — $ 2,664 Facilities 6,947 (1,084 ) (268 ) (40 ) 5,555 Asset impairment — (24 ) — 24 — Total $ 10,619 $ (146 ) $ (2,238 ) $ (16 ) $ 8,219

Accumulated Other Comprehensi31

Accumulated Other Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Summary of Changes in Accumulated Other Comprehensive Income (Loss)	The following table sets forth the changes in accumulated other comprehensive income by component for the three months ended March 31, 2018 (in thousands): Unrealized Loss on Other Available-for-Sale Securities Foreign Currency Translation Accumulated Tax Effect Total Balance at December 30, 2017 $ (418 ) $ 7,551 $ (879 ) $ 6,254 Net current-period other comprehensive loss (125 ) (4,816 ) — (4,941 ) Balance at March 31, 2018 $ (543 ) $ 2,735 $ (879 ) $ 1,313

Basic and Diluted Net Loss Pe32

Basic and Diluted Net Loss Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Computation of Net Income (Loss) Per Common Share Basic and Diluted	The following table sets forth the computation of net loss per common share – basic and diluted (in thousands, except per share amounts): Three Months Ended March 31, 2018 April 1, 2017 Net loss $ (26,280 ) $ (40,451 ) Weighted average common shares outstanding - basic and diluted 150,333 145,786 Net loss per common share - basic and diluted $ (0.17 ) $ (0.28 )
Antidilutive Shares Excluded from Computation of Diluted Net Income (Loss) Per Share	The following sets forth the potentially dilutive shares excluded from the computation of the diluted net loss per share because their effect was anti-dilutive (in thousands): Three Months Ended March 31, 2018 April 1, 2017 Stock options 1,187 1,634 RSUs 9,439 7,773 PSUs 1,545 1,414 ESPP shares 2,247 953 Total 14,418 11,774

Convertible Senior Notes (Table

Convertible Senior Notes (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Components of Convertible Senior Notes	The net carrying amounts of the debt obligation were as follows (in thousands): March 31, 2018 December 30, 2017 Principal $ 150,000 $ 150,000 Unamortized discount (1) (1,891 ) (4,670 ) Unamortized issuance cost (1) (163 ) (402 ) Net carrying amount $ 147,946 $ 144,928 (1) Unamortized debt conversion discount and issuance costs will be amortized over the remaining life of the Notes, which is approximately 2 months from March 31, 2018.
Interest Expense Recognized Related To Notes	The following table sets forth total interest expense recognized related to the Notes (in thousands): Three Months Ended March 31, 2018 April 1, 2017 Contractual interest expense $ 656 $ 656 Amortization of debt issuance costs 239 216 Amortization of debt discount 2,779 2,514 Total interest expense $ 3,674 $ 3,386

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Company's Equity Award Activity - Options	The following tables summarize the Company’s equity award activity and related information (in thousands, except per share data): Number of Stock Options Weighted-Average Exercise Price Per Share Aggregate Intrinsic Value Outstanding at December 30, 2017 1,397 $ 8.11 $ 1 Stock options granted — $ — Stock options exercised (162 ) $ 7.79 $ 340 Stock options canceled (48 ) $ 11.47 Outstanding at March 31, 2018 1,187 $ 8.02 $ 3,380 Exercisable at March 31, 2018 1,187 $ 8.02 $ 3,380
Summary of Company's Equity Award Activity - RSUs	Number of Restricted Stock Units Weighted- Average Grant Date Fair Value Per Share Aggregate Intrinsic Value Outstanding at December 30, 2017 6,791 $ 11.55 $ 42,988 RSUs granted 3,151 $ 11.01 RSUs released (264 ) $ 11.78 $ 2,065 RSUs canceled (239 ) $ 11.18 Outstanding at March 31, 2018 9,439 $ 11.37 $ 102,510
Summary of Company's Equity Award Activity - PSUs	Number of Performance Stock Units Weighted- Average Grant Date Fair Value Per Share Aggregate Intrinsic Value Outstanding at December 30, 2017 1,367 $ 16.28 $ 8,651 PSUs granted 505 $ 15.87 PSUs released — $ — $ — PSUs canceled (327 ) $ 15.75 Outstanding at March 31, 2018 1,545 $ 16.25 $ 16,771 Expected to vest at March 31, 2018 1,098 $ 11,928
Total Stock Based Compensation Cost for Instruments Granted but Not Yet Amortized	The following table presents total stock-based compensation cost for instruments granted but not yet amortized, net of estimated forfeitures, of the Company’s equity compensation plans as of March 31, 2018 . These costs are expected to be amortized on a straight-line basis over the following weighted-average periods (in thousands, except for weighted-average period): Unrecognized Compensation Expense, Net Weighted- Average Period (in years) RSUs $ 80,840 3.0 PSUs $ 14,328 1.8
Estimated Fair Value of ESPP Shares	The fair value of the shares was estimated at the date of grant using the following assumptions (expense amounts in thousands): Three Months Ended Employee Stock Purchase Plan March 31, 2018 April 1, 2017 Volatility 62% 51% Risk-free interest rate 1.90% 0.81% Expected life 0.5 years 0.5 years Estimated fair value $3.13 $3.46 Total stock-based compensation expense $1,555 $1,681
Schedule of Share-based Payment Award, Valuation Assumptions	The ranges of estimated values of the PSUs granted that are compared to the index, as well as the assumptions used in calculating these values were based on estimates as follows: 2018 2017 2016 Index SPGIIPTR SPGIIPTR SPGIIPTR Index volatility 33% 33% - 34% 18% Infinera volatility 58% - 59% 55% - 56% 55% Risk-free interest rate 2.37% - 2.40% 1.41% - 1.63% 0.95% - 1.07% Correlation with index/index component 0.04 - 0.48 0.10 - 0.49 0.58 - 0.59 Estimated fair value $14.99 - $19.46 $15.23 - $17.35 $10.31 - $16.62
Schedule of Nonvested Performance Based Units Activity by Grant Year	The following table summarizes by grant year, the Company’s PSU activity for the three months ended March 31, 2018 (in thousands): Grant Year Total Number of Performance Stock Units 2015 2016 2017 2018 Outstanding at December 30, 2017 1,367 77 420 869 — PSUs granted 505 — — — 505 PSUs released — — — — — PSUs canceled (327 ) (77 ) (189 ) (61 ) — Outstanding at March 31, 2018 1,545 — 231 808 505
Summary of Effects of Stock-Based Compensation on Company's Balance Sheets and Statements of Operations	The following tables summarize the effects of stock-based compensation on the Company’s condensed consolidated balance sheets and statements of operations for the periods presented (in thousands): March 31, 2018 December 30, 2017 Stock-based compensation effects in inventory $ 5,383 $ 5,255 Three Months Ended March 31, 2018 April 1, 2017 Stock-based compensation effects included in net loss before income taxes Cost of revenue $ (122 ) $ 724 Research and development 4,324 3,780 Sales and marketing 2,898 2,726 General and administration 2,767 2,540 $ 9,867 $ 9,770 Cost of revenue – amortization from balance sheet (1) 1,116 1,107 Total stock-based compensation expense $ 10,983 $ 10,877 (1) Stock-based compensation expense deferred to inventory and deferred inventory costs in prior periods and recognized in the current period.

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Table of Long Lived Assets	The following table sets forth long-lived assets by geographic region (in thousands): March 31, 2018 December 30, 2017 United States $ 127,851 $ 128,582 Other Americas 1,323 661 Europe, Middle East and Africa 3,310 3,527 Asia Pacific 2,712 3,172 Total property, plant and equipment, net $ 135,196 $ 135,942

Guarantees (Tables)

Guarantees (Tables)	3 Months Ended
	Mar. 31, 2018
Guarantees [Abstract]
Activity Related to Product Warranty	Activity related to product warranty was as follows (in thousands): Three Months Ended March 31, 2018 April 1, 2017 Beginning balance $ 30,909 $ 40,342 Charges to operations 4,357 4,659 Utilization (4,438 ) (3,388 ) Change in estimate (1) 20 (5,633 ) Balance at the end of the period $ 30,848 $ 35,980 (1) The Company records product warranty liabilities based on the latest quality and cost information available as of the date the revenue is recorded. The changes in estimate shown here are due to changes in overall actual failure rates, the mix of new versus used units related to replacement of failed units, and changes in the estimated cost of repair. As the Company's products mature over time, failure rates and repair costs generally decline leading to favorable changes in warranty reserves. In addition, during the first quarter of 2017, due to product quality improvements, the Company revised certain estimates used in calculating its product warranties that resulted in a one-time reduction to the warranty accrual of $2.2 million .

Basis of Presentation and Sig37

Basis of Presentation and Significant Accounting Policies (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Dec. 30, 2017
Sales revenue, net | Customer concentration risk | Customer One
Concentration Risk [Line Items]
Concentration risk	29.00%	19.00%
Sales revenue, net | Customer concentration risk | Customer Two
Concentration Risk [Line Items]
Concentration risk	11.00%
1.75% Convertible Senior Notes Due June 1, 2018
Concentration Risk [Line Items]
Principal amount	$ 150,000,000		$ 150,000,000
Debt instrument interest percentage	1.75%

Revenue Recognition - Narrative

Revenue Recognition - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Dec. 31, 2017	Dec. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit	$ (768,955)		$ (742,675)	$ (758,081)
Revenues	202,681	$ 175,522
Capitalized cost to obtain contract	500
Deferred revenue recognized	14,500
Adjustments | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit				$ 15,406
Revenues	$ 3,226
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Payment term	30 days
Purchase commitment time frame	12 months
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Payment term	120 days
Purchase commitment time frame	24 months

Revenue Recognition - Disaggreg

Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Disaggregation of Revenue [Line Items]
Product	$ 171,629	$ 147,053
Services	31,052	28,469
Total revenue	202,681	175,522
United States
Disaggregation of Revenue [Line Items]
Total revenue	129,025	99,780
Other Americas
Disaggregation of Revenue [Line Items]
Total revenue	5,215	6,035
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenue	59,199	57,413
Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenue	9,242	12,294
Direct
Disaggregation of Revenue [Line Items]
Total revenue	188,462	165,946
Indirect
Disaggregation of Revenue [Line Items]
Total revenue	$ 14,219	$ 9,576

Revenue Recognition - Contract

Revenue Recognition - Contract with Customer, Asset and Liability (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Dec. 30, 2017
Revenue from Contract with Customer [Abstract]
Accounts receivable, net	$ 161,541	$ 135,245	$ 126,152
Receivables and contract assets	2,670	2,825
Deferred revenue	$ 71,641	$ 75,458

Revenue Recognition - Revenue,

Revenue Recognition - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Details) $ in Thousands	Mar. 31, 2018USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-12-31
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized in the future as of March 31, 2018	$ 167,860
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-12-31
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized in the future as of March 31, 2018	16,382
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-12-31
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized in the future as of March 31, 2018	13,040
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-12-31
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized in the future as of March 31, 2018	2,716
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-12-31
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized in the future as of March 31, 2018	1,972
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-12-31
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized in the future as of March 31, 2018	1,876
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized in the future as of March 31, 2018	$ 203,846

Revenue Recognition - Schedule

Revenue Recognition - Schedule of New Accounting Pronouncements and Changes in Accounting Principles (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Dec. 31, 2017	Dec. 30, 2017
Revenue
Product	$ 171,629	$ 147,053
Services	31,052	28,469
Revenues	202,681	175,522
Costs and expenses
Cost of revenue	120,513	111,466
Net loss	(26,280)	$ (40,451)
Assets
Accounts receivable, net	161,541		$ 135,245	$ 126,152
Inventory	215,888		214,465	214,704
Prepaid expenses and other current assets			46,070	43,339
Liabilities
Accrued expenses	51,955		55,427	39,782
Deferred revenue			75,458	94,923
Equity
Accumulated deficit	(768,955)		$ (742,675)	(758,081)
Balances Without Adoption of ASC 606
Revenue
Product	173,573
Services	32,334
Revenues	205,907
Costs and expenses
Cost of revenue	121,041
Net loss	(23,582)
Accounting Standards Update 2014-09 | Adjustments
Revenue
Product	1,944
Services	1,282
Revenues	3,226
Costs and expenses
Cost of revenue	528
Net loss	$ 2,698
Assets
Accounts receivable, net				9,093
Inventory				(239)
Prepaid expenses and other current assets				2,731
Liabilities
Accrued expenses				15,645
Deferred revenue				(19,465)
Equity
Accumulated deficit				$ 15,406

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair value, measurements, recurring - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 30, 2017
Assets
Total assets	$ 204,510	$ 206,969
Foreign currency exchange forward contracts
Liabilities
Foreign currency exchange forward contracts	(29)	(204)
Money market funds
Assets
Total assets	24,393	20,371
Certificates of deposit
Assets
Total assets	240	240
Commercial paper
Assets
Total assets	46,834	26,912
Corporate bonds
Assets
Total assets	96,650	118,558
U.S. agency notes
Assets
Total assets	5,477	5,480
U.S. treasuries
Assets
Total assets	30,916	35,408
Level 1
Assets
Total assets	55,309	55,779
Level 1 | Foreign currency exchange forward contracts
Liabilities
Foreign currency exchange forward contracts	0	0
Level 1 | Money market funds
Assets
Total assets	24,393	20,371
Level 1 | Certificates of deposit
Assets
Total assets	0	0
Level 1 | Commercial paper
Assets
Total assets	0	0
Level 1 | Corporate bonds
Assets
Total assets	0	0
Level 1 | U.S. agency notes
Assets
Total assets	0	0
Level 1 | U.S. treasuries
Assets
Total assets	30,916	35,408
Level 2
Assets
Total assets	149,201	151,190
Level 2 | Foreign currency exchange forward contracts
Liabilities
Foreign currency exchange forward contracts	(29)	(204)
Level 2 | Money market funds
Assets
Total assets	0	0
Level 2 | Certificates of deposit
Assets
Total assets	240	240
Level 2 | Commercial paper
Assets
Total assets	46,834	26,912
Level 2 | Corporate bonds
Assets
Total assets	96,650	118,558
Level 2 | U.S. agency notes
Assets
Total assets	5,477	5,480
Level 2 | U.S. treasuries
Assets
Total assets	$ 0	$ 0

Fair Value Measurements - Inves

Fair Value Measurements - Investments at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 30, 2017
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cash	$ 78,195	$ 87,991
Adjusted Amortized Cost	283,247	295,378
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(542)	(418)
Fair Value	282,705	294,960
Cash and Cash Equivalents
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost	151,444	116,346
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(8)	(1)
Fair Value	151,436	116,345
Cash and Cash Equivalents | Money market funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost	24,393	20,371
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	24,393	20,371
Cash and Cash Equivalents | Commercial paper
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost	36,357
Gross Unrealized Gains	0
Gross Unrealized Losses	(8)
Fair Value	36,349
Cash and Cash Equivalents | Corporate bonds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost	2,515
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	2,515
Cash and Cash Equivalents | U.S. treasuries
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost	9,984	7,984
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(1)
Fair Value	9,984	7,983
Short-term Investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost	113,217	147,844
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(331)	(248)
Fair Value	112,886	147,596
Short-term Investments | Commercial paper
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost	10,490	26,924
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(5)	(12)
Fair Value	10,485	26,912
Short-term Investments | Certificates of deposit
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost	240	240
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	240	240
Short-term Investments | Corporate bonds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost	75,998	90,685
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(246)	(155)
Fair Value	75,752	90,530
Short-term Investments | U.S. agency notes
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost	5,500	2,500
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(23)	(11)
Fair Value	5,477	2,489
Short-term Investments | U.S. treasuries
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost	20,989	27,495
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(57)	(70)
Fair Value	20,932	27,425
Other Long-term Investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost	18,586	31,188
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(203)	(169)
Fair Value	18,383	31,019
Other Long-term Investments | Corporate bonds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost	18,586	28,186
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(203)	(158)
Fair Value	$ 18,383	28,028
Other Long-term Investments | U.S. agency notes
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Adjusted Amortized Cost		3,002
Gross Unrealized Gains		0
Gross Unrealized Losses		(11)
Fair Value		$ 2,991

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 30, 2017	Apr. 01, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	18 months
Cash, cash equivalents and short-term investments	$ 264,300,000
Cash and cash equivalents held by foreign subsidiaries	151,436,000	$ 116,345,000	$ 125,658,000
Foreign Subsidiary
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents held by foreign subsidiaries	50,000,000
Operating Expenses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Facilities	(1,084,000)	7,300,000
Cost-method Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment charge on cost-method investments	$ 0	$ 1,900,000

Cost-method Investment (Details

Cost-method Investment (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 30, 2017	Dec. 31, 2016
Gain (Loss) on Investments [Line Items]
Cost-method investment, total	$ 5,110,000	$ 5,110,000
Cost-method Investments
Gain (Loss) on Investments [Line Items]
Purchase of cost-method investment			$ 7,000,000
Cost-method investment, preferred stock warrant issued			$ 10,000,000
Cost-method investment, total	$ 5,100,000	5,100,000
Less than percent of voting securities (less than)	20.00%
Impairment charge on cost-method investments	$ 0	$ 1,900,000

Derivative Instruments - Narrat

Derivative Instruments - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Posted collateral	$ 0.9
Before-tax effect of foreign currency exchange forward contracts not designated as hedging instruments, gain (loss)	$ (0.6)	$ (0.3)

Derivative Instruments - Fair V

Derivative Instruments - Fair Value of Derivative Instruments Not Designated as Hedging Activities (Details) - Not designated as hedging instrument - USD ($)	Mar. 31, 2018	Dec. 30, 2017
Derivative [Line Items]
Other Accrued Liabilities	$ (29,000)	$ (204,000)
Related to euro denominated receivables
Derivative [Line Items]
Gross Notional	23,335,000	24,794,000
Other Accrued Liabilities	(29,000)	(202,000)
Related to euro denominated restricted cash
Derivative [Line Items]
Gross Notional	259,000	252,000
Other Accrued Liabilities	$ 0	$ (2,000)

Goodwill and Intangible Asset49

Goodwill and Intangible Assets - Goodwill Roll Forward (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Goodwill [Roll Forward]
Balance as of December 30, 2017	$ 195,615
Foreign currency translation adjustments	(3,053)
Balance as of March 31, 2018	$ 192,562

Goodwill and Intangible Asset50

Goodwill and Intangible Assets - Purchased Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 30, 2017
Intangible assets with finite lives:
Gross Carrying Amount	$ 153,325	$ 155,758
Accumulated Amortization	(69,367)	(63,570)
Net Carrying Amount	$ 83,958	$ 92,188
Weighted average remaining useful life (in years)	3 years 7 months 23 days	3 years 10 months 8 days
Customer relationships
Intangible assets with finite lives:
Gross Carrying Amount	$ 50,253	$ 51,050
Accumulated Amortization	(16,343)	(15,007)
Net Carrying Amount	$ 33,910	$ 36,043
Weighted average remaining useful life (in years)	5 years 4 months 20 days	5 years 7 months 20 days
Developed technology
Intangible assets with finite lives:
Gross Carrying Amount	$ 103,072	$ 104,708
Accumulated Amortization	(53,024)	(48,563)
Net Carrying Amount	$ 50,048	$ 56,145
Weighted average remaining useful life (in years)	2 years 5 months 18 days	2 years 8 months 15 days

Goodwill and Intangible Asset51

Goodwill and Intangible Assets - Future Amortization Expense (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Net Carrying Amount	$ 83,958	$ 92,188
Remainder of 2018	20,370
2,019	26,548
2,020	19,372
2,021	7,082
2,022	6,466
2023 and Thereafter	$ 4,120

Goodwill and Intangible Asset52

Goodwill and Intangible Assets - Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Dec. 30, 2017
Intangible assets with finite lives:
Goodwill impairment	$ 0
Amortization expense	6,900	$ 6,300
Impairment charge	$ 0	252
Other intangible assets
Intangible assets with finite lives:
Impairment charge			$ 300
Developed technology
Intangible assets with finite lives:
Finite-lived intangible assets, period increase (decrease)		$ 300
Finite-lived intangible asset, useful life		5 years

Balance Sheet Details (Details)

Balance Sheet Details (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Dec. 30, 2017
Inventory
Raw materials	$ 30,303		$ 27,568
Work in process	66,499		59,662
Finished goods	119,086		127,474
Total inventory	215,888	$ 214,465	214,704
Property, plant and equipment, net
Property, plant and equipment, gross	388,244		385,894
Less accumulated depreciation and amortization	(253,048)		(249,952)
Total property, plant and equipment, net	135,196		135,942
Accrued expenses
Loss contingency related to non-cancelable purchase commitments	6,207		6,379
Professional and other consulting fees	4,837		5,305
Taxes payable	3,864		3,707
Royalties	5,447		5,404
Restructuring accrual	4,273		5,490
Right of return	12,756		0
Other accrued expenses	14,571		13,497
Total accrued expenses	51,955	$ 55,427	39,782
Computer hardware
Property, plant and equipment, net
Property, plant and equipment, gross	14,098		13,881
Computer software
Property, plant and equipment, net
Property, plant and equipment, gross	32,791		32,521
Laboratory and manufacturing equipment
Property, plant and equipment, net
Property, plant and equipment, gross	250,562		246,380
Land and building
Property, plant and equipment, net
Property, plant and equipment, gross	12,347		12,347
Furniture and fixtures
Property, plant and equipment, net
Property, plant and equipment, gross	2,547		2,474
Leasehold and building improvements
Property, plant and equipment, net
Property, plant and equipment, gross	43,301		43,475
Construction in progress
Property, plant and equipment, net
Property, plant and equipment, gross	32,598		34,816
Enterprise resource planning systems
Property, plant and equipment, net
Property, plant and equipment, gross	11,400		11,400
Total property, plant and equipment, net	$ 4,200		$ 4,700

Restructuring and Other Relat54

Restructuring and Other Related Costs - Restructuring and Other Related Costs (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 30, 2017
Restructuring Cost and Reserve [Line Items]
Total	$ (146)
Cost of Revenue
Restructuring Cost and Reserve [Line Items]
Severance and related expenses	17
Facilities	0
Asset impairment	0
Total	17
Operating Expenses
Restructuring Cost and Reserve [Line Items]
Severance and related expenses	945
Facilities	(1,084)	$ 7,300
Asset impairment	(24)
Total	$ (163)

Restructuring and Other Relat55

Restructuring and Other Related Costs - Schedule of Restructuring Reserve by Type of Cost (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Restructuring Reserve [Roll Forward]
Beginning balance	$ 10,619
Charges (Credits)	(146)
Cash	(2,238)
Non-cash Settlements and Other	(16)
Ending balance	8,219
Severance and related expenses
Restructuring Reserve [Roll Forward]
Beginning balance	3,672
Charges (Credits)	962
Cash	(1,970)
Non-cash Settlements and Other	0
Ending balance	2,664
Facilities
Restructuring Reserve [Roll Forward]
Beginning balance	6,947
Charges (Credits)	(1,084)
Cash	(268)
Non-cash Settlements and Other	(40)
Ending balance	5,555
Asset impairment
Restructuring Reserve [Roll Forward]
Beginning balance	0
Charges (Credits)	(24)
Cash	0
Non-cash Settlements and Other	24
Ending balance	$ 0

Restructuring and Other Relat56

Restructuring and Other Related Costs - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 30, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring liability	$ 8,219	$ 10,619
Facility closures
Restructuring Cost and Reserve [Line Items]
Restructuring liability	5,555	6,947
Severance and related expenses
Restructuring Cost and Reserve [Line Items]
Restructuring liability	$ 2,664	$ 3,672

Accumulated Other Comprehensi57

Accumulated Other Comprehensive Income (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ (879)
Beginning balance	6,254
Net current-period other comprehensive loss	0
Net current-period other comprehensive loss	(4,941)
Ending balance	(879)
Ending balance	1,313
Unrealized Loss on Other Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(418)
Net current-period other comprehensive loss	(125)
Ending balance	(543)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	7,551
Net current-period other comprehensive loss	(4,816)
Ending balance	$ 2,735

Basic and Diluted Net Loss Pe58

Basic and Diluted Net Loss Per Common Share - Computation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Earnings Per Share [Abstract]
Net loss	$ (26,280)	$ (40,451)
Weighted average common shares outstanding - basic and diluted (in shares)	150,333	145,786
Net loss per common share - basic and diluted (in dollars per share)	$ (0.17)	$ (0.28)

Basic and Diluted Net Loss Pe59

Basic and Diluted Net Loss Per Common Share - Antidilutive Shares (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share computation (in shares)	14,418	11,774
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share computation (in shares)	1,187	1,634
RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share computation (in shares)	9,439	7,773
PSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share computation (in shares)	1,545	1,414
ESPP shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share computation (in shares)	2,247	953

Convertible Senior Notes - Narr

Convertible Senior Notes - Narrative (Details)	May 30, 2013USD ($)$ / shares	May 30, 2013USD ($)$ / shares	Mar. 31, 2018USD ($)d	Mar. 29, 2018$ / shares	Dec. 30, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 24, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchase price as a percentage on principal amount of the notes upon the occurrence of a fundamental change			100.00%
Debt issuance costs, gross	$ 5,500,000	$ 5,500,000
Total estimated fair value of the notes			$ 151,100,000
Closing price of common stock (in usd per share) | $ / shares				$ 10.86
Long-term debt | Accounting Standards Update 2015-03
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt issuance cost increase (decrease)					$ 2,100,000
Other noncurrent assets | Accounting Standards Update 2015-03
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt issuance cost increase (decrease)						$ (2,100,000)
1.75% Convertible Senior Notes Due June 1, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from issuance of debt, net		$ 144,500,000
Initial conversion rate per $1,000 principal amount of Notes	0.0794834
Initial conversion price (in usd per share) | $ / shares	$ 12.58	$ 12.58
Net equity component carrying amount			43,300,000		$ 43,300,000
Deferred tax liability			$ 17,000,000
Debt instrument interest percentage			1.75%
Additional effective rate of interest to be used on amortized carrying value			10.23%				10.23%
Convertible senior notes, conversion circumstance one
Accounts, Notes, Loans and Financing Receivable [Line Items]
Threshold trading days for debt instrument conversion | d			20
Convertible threshold consecutive trading days | d			30
Convertible threshold minimum percentage			130.00%
Convertible senior notes, conversion circumstance two
Accounts, Notes, Loans and Financing Receivable [Line Items]
Convertible threshold consecutive trading days | d			5
Convertible threshold business days | d			5
Debt instrument, convertible, if-converted value in excess of principal			$ 1,000
Convertible, threshold maximum percentage			98.00%

Convertible Senior Notes - Comp

Convertible Senior Notes - Components of Convertible Senior Notes (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 30, 2017
Debt Instrument [Line Items]
Remaining life	2 months
1.75% Convertible Senior Notes Due June 1, 2018
Debt Instrument [Line Items]
Principal amount	$ 150,000,000	$ 150,000,000
Unamortized discount	(1,891,000)	(4,670,000)
Unamortized issuance cost	(163,000)	(402,000)
Net carrying amount	$ 147,946,000	$ 144,928,000

Convertible Senior Notes - Inte

Convertible Senior Notes - Interest Expense Recognized Related to Notes Prior to Capitalization of Interest (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Debt Disclosure [Abstract]
Contractual interest expense	$ 656	$ 656
Amortization of debt issuance costs	239	216
Amortization of debt discount	2,779	2,514
Total interest expense	$ 3,674	$ 3,386

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)shares	Apr. 01, 2017USD ($)	Mar. 29, 2018$ / shares	May 31, 2017shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing price of common stock (in usd per share) | $ / shares			$ 10.86
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units granted (in shares)	3,151,000
Amortization of stock-based compensation | $	$ 7.4	$ 7.7
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units granted (in shares)	505,000
Performance stock unit grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amortization of stock-based compensation | $	$ 2.1	$ 1.8
2016 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in shares authorized (in shares)				6,400,000
Reserved common stock for issuance of options (in shares)	13,900,000
2016 Plan maximum term	10 years
2016 Equity Incentive Plan | PSUs | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ranges of number of shares issued on vesting of PSUs		0
2016 Equity Incentive Plan | PSUs | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ranges of number of shares issued on vesting of PSUs		2
2016 Equity Incentive Plan | PSUs | Existing employees | Vesting 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Duration of grants based on shareholder return of common stock price versus designated index		1 year
2016 Equity Incentive Plan | PSUs | Existing employees | Vesting 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Duration of grants based on shareholder return of common stock price versus designated index		2 years
2016 Equity Incentive Plan | PSUs | Existing employees | Vesting 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Duration of grants based on shareholder return of common stock price versus designated index		3 years
2007 Equity Incentive Plan | PSUs | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ranges of number of shares issued on vesting of PSUs	0
2007 Equity Incentive Plan | PSUs | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ranges of number of shares issued on vesting of PSUs	2
2007 Equity Incentive Plan | PSUs | Existing employees | Vesting 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Duration of grants based on shareholder return of common stock price versus designated index	1 year
2007 Equity Incentive Plan | PSUs | Existing employees | Vesting 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Duration of grants based on shareholder return of common stock price versus designated index	2 years
2007 Equity Incentive Plan | PSUs | Existing employees | Vesting 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Duration of grants based on shareholder return of common stock price versus designated index	3 years

Stockholders' Equity - Equity A

Stockholders' Equity - Equity Award Activity - Options (Details) - Stock options $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)$ / sharesshares
Number of Stock Options
Stock options, beginning balance (in shares) | shares	1,397
Stock options, granted (in shares) | shares	0
Stock options, exercised (in shares) | shares	(162)
Stock options, canceled (in shares) | shares	(48)
Stock options, ending balance (in shares) | shares	1,187
Stock options, exercisable (in shares) | shares	1,187
Weighted-Average Exercise Price Per Share
Weighted-average exercise price per share, beginning balance (in usd per share) | $ / shares	$ 8.11
Weighted-average exercise per share, options granted (in usd per share) | $ / shares	0
Weighted-average exercise price per share, options exercised (in usd per share) | $ / shares	7.79
Weighted-average exercise price per share, options canceled (in usd per share) | $ / shares	11.47
Weighted-average exercise price per share, ending balance (in usd per share) | $ / shares	8.02
Average exercise price per share, exercisable (in usd per share) | $ / shares	$ 8.02
Aggregate Intrinsic Value
Aggregate intrinsic value, beginning balance | $	$ 1
Aggregate intrinsic value, options exercised | $	340
Aggregate intrinsic value, ending balance | $	3,380
Aggregate intrinsic value, exercisable | $	$ 3,380

Stockholders' Equity - Equity65

Stockholders' Equity - Equity Award Activity - RSUs (Details) - Restricted stock units $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)$ / sharesshares
Number of Restricted Stock Units
Number of units, beginning balance (in shares) | shares	6,791
Number of units granted (in shares) | shares	3,151
Number of units released (in shares) | shares	(264)
Number units canceled (in shares) | shares	(239)
Number of units, ending balance (in shares) | shares	9,439
Weighted- Average Grant Date Fair Value Per Share
Weighted-average grant date fair value per share, beginning balance (in usd per share) | $ / shares	$ 11.55
Weighted-average grant date fair value per share, granted (in usd per share) | $ / shares	11.01
Weighted-average grant date fair value per share, released (in usd per share) | $ / shares	11.78
Weighted-average grant date fair value per share, canceled (in usd per share) | $ / shares	11.18
Weighted-average grant date fair value per share, ending balance (in usd per share) | $ / shares	$ 11.37
Aggregate Intrinsic Value
Aggregate intrinsic value, beginning balance | $	$ 42,988
Aggregate intrinsic value, RSUs released | $	2,065
Aggregate intrinsic value, ending balance | $	$ 102,510

Stockholders' Equity - Equity66

Stockholders' Equity - Equity Award Activity - PSUs (Details) - PSUs $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)$ / sharesshares
Number of Performance Stock Units
Number of units, beginning balance (in shares)	1,367
Number of units granted (in shares)	505
Number of units released (in shares)	0
Number units canceled (in shares)	(327)
Number of units, ending balance (in shares)	1,545
Number of restricted stock units, expected to vest (in shares)	1,098
Weighted- Average Grant Date Fair Value Per Share
Weighted-average grant date fair value per share, beginning balance (in usd per share) | $ / shares	$ 16.28
Weighted-average grant date fair value per share, granted (in usd per share) | $ / shares	15.87
Weighted-average grant date fair value per share, released (in usd per share) | $ / shares	0
Weighted-average grant date fair value per share, canceled (in usd per share) | $ / shares	15.75
Weighted-average grant date fair value per share, ending balance (in usd per share) | $ / shares	$ 16.25
Aggregate Intrinsic Value
Aggregate intrinsic value, beginning balance | $	$ 8,651
Aggregate Intrinsic Value, PSUs released | $	0
Aggregate intrinsic value, ending balance | $	16,771
Aggregate intrinsic value, expected to vest | $	$ 11,928

Stockholders' Equity - Total St

Stockholders' Equity - Total Stock Based Compensation Cost for Instruments Granted but Not Yet Amortized (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, net	$ 80,840
Weighted-average period	3 years
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, net	$ 14,328
Weighted-average period	1 year 9 months 18 days

Stockholders' Equity - Estimate

Stockholders' Equity - Estimated Fair Value of ESPP, Valuation Assumptions (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 10,983	$ 10,877
Employee Stock Purchase Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility	62.00%	51.00%
Risk-free interest rate	1.90%	0.81%
Expected life	6 months	6 months
Estimated fair value (in usd per share)	$ 3.13	$ 3.46
Total stock-based compensation expense	$ 1,555	$ 1,681

Stockholders' Equity - Valuatio

Stockholders' Equity - Valuation Assumptions (Details) - PSUs	3 Months Ended	12 Months Ended
	Mar. 31, 2018$ / shares	Dec. 30, 2017$ / shares	Dec. 31, 2016$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Index volatility	33.00%		18.00%
Infinera volatility			55.00%
Volatility minimum	58.00%	55.00%
Volatility maximum	59.00%	56.00%
Risk-free interest rate minimum	2.37%	1.41%	0.95%
Risk-free interest rate maximum	2.40%	1.63%	1.07%
Estimated fair value (in dollars per share)	$ 15.87
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Index volatility		33.00%
Correlation with index/index component	0.04	0.10	0.58
Estimated fair value (in dollars per share)	$ 14.99	$ 15.23	$ 10.31
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Index volatility		34.00%
Correlation with index/index component	0.48	0.49	0.59
Estimated fair value (in dollars per share)	$ 19.46	$ 17.35	$ 16.62

Stockholders' Equity - Nonveste

Stockholders' Equity - Nonvested Performance Based Units Activity By Grant Year (Details) - PSUs shares in Thousands	3 Months Ended
	Mar. 31, 2018shares
Number of Performance Stock Units
Number of units, beginning balance (in shares)	1,367
Number of units granted (in shares)	505
Number of units released (in shares)	0
Number units canceled (in shares)	(327)
Number of units, ending balance (in shares)	1,545
2,015
Number of Performance Stock Units
Number of units, beginning balance (in shares)	77
Number of units granted (in shares)	0
Number of units released (in shares)	0
Number units canceled (in shares)	(77)
Number of units, ending balance (in shares)	0
2,016
Number of Performance Stock Units
Number of units, beginning balance (in shares)	420
Number of units granted (in shares)	0
Number of units released (in shares)	0
Number units canceled (in shares)	(189)
Number of units, ending balance (in shares)	231
2,017
Number of Performance Stock Units
Number of units, beginning balance (in shares)	869
Number of units granted (in shares)	0
Number of units released (in shares)	0
Number units canceled (in shares)	(61)
Number of units, ending balance (in shares)	808
2,018
Number of Performance Stock Units
Number of units, beginning balance (in shares)	0
Number of units granted (in shares)	505
Number of units released (in shares)	0
Number units canceled (in shares)	0
Number of units, ending balance (in shares)	505

Stockholders' Equity - Balance

Stockholders' Equity - Balance Sheet and Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Dec. 30, 2017
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	$ 9,867	$ 9,770
Cost of revenue – amortization from balance sheet	1,116	1,107
Total stock-based compensation expense	10,983	10,877
Cost of revenue
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	(122)	724
Research and development
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	4,324	3,780
Sales and marketing
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	2,898	2,726
General and administration
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	2,767	$ 2,540
Stock-based compensation effects in inventory
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects in inventory	$ 5,383		$ 5,255

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Income Tax Disclosure [Abstract]
Provision (benefit) for income taxes	$ (678)	$ (158)
Pre-tax income (loss)	(26,958)	$ (40,609)
Income tax benefit increase	$ 500

Segment Information (Details)

Segment Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)segment	Dec. 30, 2017USD ($)
Geographic Information For Property Plant And Equipment [Line Items]
Number of business activities | segment	1
Number of reporting segments | segment	1
Total property, plant and equipment, net	$ 135,196	$ 135,942
United States
Geographic Information For Property Plant And Equipment [Line Items]
Total property, plant and equipment, net	127,851	128,582
Other Americas
Geographic Information For Property Plant And Equipment [Line Items]
Total property, plant and equipment, net	1,323	661
Europe, Middle East and Africa
Geographic Information For Property Plant And Equipment [Line Items]
Total property, plant and equipment, net	3,310	3,527
Asia Pacific
Geographic Information For Property Plant And Equipment [Line Items]
Total property, plant and equipment, net	$ 2,712	$ 3,172

Guarantees - Activity Related t

Guarantees - Activity Related to Warranty (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Movement in Standard Product Warranty Accrual [Roll Forward]
Beginning balance	$ 30,909	$ 40,342
Charges to operations	4,357	4,659
Utilization	(4,438)	(3,388)
Change in estimate	20	(5,633)
Balance at the end of the period	$ 30,848	35,980
Product Quality Improvements
Movement in Standard Product Warranty Accrual [Roll Forward]
Change in estimate		$ (2,200)

Guarantees - Narrative (Details

Guarantees - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 30, 2017
Guarantor Obligations [Line Items]
Outstanding standby letters of credit	$ 3.7	$ 4.2
Debt instrument, collateral amount	5.3	5.2
Banker's guarantees or performance bonds
Guarantor Obligations [Line Items]
Line of credit facility, remaining borrowing capacity	1.6	1.6
Proceeds from lines of credit	0	0
Letter of credit
Guarantor Obligations [Line Items]
Customer performance guarantee	1.7	2.2
Value added tax license	1.3	1.3
Property leases	$ 0.7	$ 0.7