Infinera (INFN) 10-Q 9 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 30, 2019	May 04, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	INFN
Entity Registrant Name	INFINERA CORP
Entity Central Index Key	0001138639
Current Fiscal Year End Date	--12-28
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding (in shares)		177,780,904

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 29, 2018
Current assets:
Cash and cash equivalents	$ 167,259	$ 202,954
Short-term investments	16,022	26,511
Short-term restricted cash	4,671	13,229
Accounts receivable, net of allowance for doubtful accounts of $5,276 in 2019 and $5,084 in 2018	267,117	317,115
Inventory	332,495	311,888
Prepaid expenses and other current assets	87,871	85,400
Total current assets	875,435	957,097
Property, plant and equipment, net	161,146	342,820
Operating lease right-of-use assets	65,598
Intangible assets	215,964	233,119
Goodwill	221,517	227,231
Long-term restricted cash	23,316	26,154
Other non-current assets	11,975	14,849
Total assets	1,574,951	1,801,270
Current liabilities:
Accounts payable	163,834	191,187
Accrued expenses and other current liabilities	141,087	131,891
Accrued compensation and related benefits	71,973	71,152
Accrued warranty	19,187	20,103
Deferred revenue	95,344	88,534
Total current liabilities	491,425	502,867
Long-term debt, net	279,738	266,929
Long-term financing lease obligation	0	193,538
Accrued warranty, non-current	20,564	20,918
Deferred revenue, non-current	30,727	31,768
Deferred tax liability	11,423	13,347
Operating lease liabilities	59,949	0
Other long-term liabilities	63,826	68,082
Commitments and contingencies (Note 19)
Stockholders’ equity:
Preferred stock, $0.001 par value Authorized shares – 25,000 and no shares issued and outstanding	0	0
Common stock, $0.001 par value Authorized shares – 500,000 as of March 30, 2019 and December 29, 2018 Issued and outstanding shares – 177,415 as of March 30, 2019 and 175,452 as of December 29, 2018	177	175
Additional paid-in capital	1,702,710	1,685,916
Accumulated other comprehensive loss	(30,714)	(25,300)
Accumulated deficit	(1,054,874)	(956,970)
Total stockholders' equity	617,299	703,821
Total liabilities and stockholders’ equity	$ 1,574,951	$ 1,801,270

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 29, 2018
Statement of Financial Position [Abstract]
Net of allowance for doubtful accounts	$ 5,276	$ 5,084
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)	177,415,000	175,452,000
Common stock, shares outstanding (in shares)	177,415,000	175,452,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Revenue:
Total revenue	$ 292,707	$ 202,681
Cost of revenue:
Amortization of intangible assets	8,252	5,341
Acquisition and integration costs	2,064	0
Restructuring and related	21,466	17
Total cost of revenue	226,275	120,513
Gross profit	66,432	82,168
Operating expenses:
Research and development	73,660	58,681
Sales and marketing	40,037	28,885
General and administrative	33,044	17,836
Amortization of intangible assets	7,057	1,607
Acquisition and integration costs	7,134	0
Restructuring and related	17,188	(163)
Total operating expenses	178,120	106,846
Loss from operations	(111,688)	(24,678)
Other income (expense), net:
Interest income	766	897
Interest expense	(7,563)	(3,683)
Other gain (loss), net	(2,923)	506
Total other income (expense), net	(9,720)	(2,280)
Loss before income taxes	(121,408)	(26,958)
Provision for (benefit from) income taxes	193	(678)
Net loss	$ (121,601)	$ (26,280)
Net loss per common share:
Basic (in usd per share)	$ (0.69)	$ (0.17)
Diluted (in usd per share)	$ (0.69)	$ (0.17)
Weighted average shares used in computing net loss per common share:
Basic (in shares)	176,406	150,333
Diluted (in shares)	176,406	150,333
Product
Revenue:
Revenue	$ 223,007	$ 171,629
Cost of revenue:
Cost of revenue	157,817	102,324
Services
Revenue:
Revenue	69,700	31,052
Cost of revenue:
Cost of revenue	$ 36,676	$ 12,831

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (121,601)	$ (26,280)
Other comprehensive income (loss), net of tax:
Change in unrealized gain (loss) on available-for-sale investments	65	(125)
Foreign currency translation adjustment	(5,557)	(4,816)
Actuarial gain on pension liabilities	78	0
Net change in accumulated other comprehensive loss	(5,414)	(4,941)
Comprehensive loss	$ (127,015)	$ (31,221)

CONSOLIDATED STATEMENT OF STOCK

CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance (in shares) at Dec. 30, 2017		149,471
Beginning balance at Dec. 30, 2017	$ 665,365	$ 149	$ 1,417,043	$ 6,254	$ (758,081)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)		162
Stock options exercised	1,260		1,260
ESPP shares issued (in shares)		1,284
ESPP shares issued	9,385	$ 2	9,383
Shares withheld for tax obligations (in shares)		(16)
Shares withheld for tax obligations	(97)		(97)
Restricted stock units released (in shares)		264
Stock-based compensation	11,111		11,111
Other comprehensive income (loss)	(4,941)			(4,941)
Net loss	(26,280)				(26,280)
Balance (in shares) at Mar. 31, 2018		151,165
Ending balance at Mar. 31, 2018	671,209	$ 151	1,438,700	1,313	(768,955)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative-effect adjustment from adoption of ASU	15,406				15,406
Balance (in shares) at Dec. 29, 2018		175,452
Beginning balance at Dec. 29, 2018	703,821	$ 175	1,685,916	(25,300)	(956,970)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
ESPP shares issued (in shares)		1,825
ESPP shares issued	7,740	$ 2	7,738
Restricted stock units released (in shares)		138
Stock-based compensation	9,056		9,056
Other comprehensive income (loss)	(5,414)			(5,414)
Net loss	(121,601)				(121,601)
Balance (in shares) at Mar. 30, 2019		177,415
Ending balance at Mar. 30, 2019	617,299	$ 177	$ 1,702,710	$ (30,714)	(1,054,874)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative-effect adjustment from adoption of ASU	$ 23,697				$ 23,697

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 30, 2019	Mar. 31, 2018
Cash Flows from Operating Activities:
Net loss		$ (121,601)	$ (26,280)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization		30,939	16,976
Non-cash restructuring and related credits		19,882	(81)
Amortization of debt discount and issuance costs		4,614	3,018
Operating lease expense, net of accretion		16,704
Stock-based compensation expense		8,713	10,983
Other loss		1,775	84
Changes in assets and liabilities:
Accounts receivable		49,754	(30,928)
Inventory		(24,937)	(2,329)
Prepaid expenses and other assets		(352)	(3,950)
Accounts payable		(23,439)	19,286
Accrued liabilities and other expenses		(25,139)	(6,181)
Deferred revenue		6,933	5,293
Net cash used in operating activities		(56,154)	(14,109)
Cash Flows from Investing Activities:
Purchase of available-for-sale investments		0	(2,986)
Proceeds from maturities of investments		10,542	50,168
Acquisition of business, net of cash acquired		(10,000)	0
Purchase of property and equipment		(6,590)	(8,019)
Net cash provided by (used in) investing activities		(6,048)	39,163
Cash Flows from Financing Activities:
Proceeds from issuance of debt, net		8,584	0
Proceeds from issuance of common stock		7,740	10,644
Minimum tax withholding paid on behalf of employees for net share settlement		0	(97)
Net cash provided by financing activities		16,324	10,547
Effect of exchange rate changes on cash and restricted cash		(1,213)	(58)
Net change in cash, cash equivalents and restricted cash		(47,091)	35,543
Cash, cash equivalents and restricted cash at beginning of period		242,337	121,486
Cash, cash equivalents and restricted cash at end of period	[1]	195,246	157,029
Supplemental disclosures of cash flow information:
Cash paid for income taxes, net of refunds		1,353	1,537
Cash paid for interest		4,315	9
Supplemental schedule of non-cash investing activities:
Transfer of inventory to fixed assets		1,805	893
Restricted Cash and Cash Equivalents [Abstract]
Total cash, cash equivalents and restricted cash		$ 242,337	$ 121,486
[1]	Reconciliation of cash, cash equivalents and restricted cash to the condensed consolidated balance sheets: March 30, 2019 March 31, 2018 (In thousands)Cash and cash equivalents$167,259 $151,436Short-term restricted cash4,671 84Long-term restricted cash23,316 5,509Total cash, cash equivalents and restricted cash$195,246 $157,029

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	3 Months Ended
	Mar. 30, 2019
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 29, 2018 . 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, employee benefit and pension plans, inventory valuation, accrued warranty, operating lease liabilities, business combinations, fair value measurement of investments and accounting for income taxes. Other less significant estimates, assumptions and judgments made by management include allowances for sales returns, allowances for doubtful accounts, useful life of intangible assets, and property, plant and equipment. 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 29, 2018 . The Company reclassified certain amounts reported in previous periods to conform to the current presentation. Effective in the fourth quarter of 2018, the Company elected to present amortization of intangible assets and acquisition and integration costs as separate line items within cost of revenue and operating expenses. As a result, the costs previously reflected in cost of revenue and operating expenses were reclassified to amortization of intangible assets and acquisition and integration costs within total cost of revenue and total operating expenses. Prior period amounts have been revised to conform to the current period presentation. This change in presentation does not affect the Company's total cost of revenue or total operating expenses. The following table shows reclassified amounts to conform to the current period's presentation: Three Months Ended March 31, 2018 Previously Reported Change in Presentation Reclassification Current Presentation Cost of revenue: Cost of product $ 107,665 $ (5,341 ) $ 102,324 Cost of services 12,831 — 12,831 Amortization of intangible assets (1) — 5,341 5,341 Restructuring and related 17 — 17 Total $ 120,513 $ — $ 120,513 Operating expenses: Research and development $ 58,681 $ — $ 58,681 Sales and marketing 30,492 (1,607 ) 28,885 General and administrative 17,836 — 17,836 Amortization of intangible assets (1) — 1,607 1,607 Restructuring and related (163 ) — (163 ) Total $ 106,846 $ — $ 106,846 (1) These lines were not previously reported in the consolidated statements of operations. To date, a few of the Company’s customers have accounted for a significant portion of its revenue. For the three months ended March 30, 2019 , one customer accounted for 11% of the Company's total revenue and for the corresponding period in 2018, two customers individually accounted for 29% and 11% 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 30, 2019 as compare d to those disclosed in the Company’s Annual Report on Form 10-K for the fiscal year ended December 29, 2018 , with the exception of the Company's lease accounting policy. Effective December 30, 2018, the Company adopted Accounting Standards Update 2016-02, “Leases (Topic 842)” ("Topic 842"). See Note 3, “Leases” 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 leases.

Leases

Leases	3 Months Ended
	Mar. 30, 2019
Leases [Abstract]
Leases	Leases Effective December 30, 2018, the Company adopted Topic 842 using the alternative modified transition method, which requires a cumulative-effect adjustment, if any, to the opening balance of retained earnings to be recognized on the date of adoption with prior periods not restated. The Company leases facilities under non-cancelable operating lease agreements. These leases have varying terms that range from one to 10 years and contain leasehold improvement incentives, rent holidays and escalation clauses. In addition, some of these leases have renewal options for up to five years . The Company determines if an arrangement contains a lease at inception. Operating leases are included in operating lease ROU assets, accrued expenses and operating lease liabilities on the Company's consolidated balance sheets. The Company does not have any finance leases. Operating lease ROU assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As most of the Company's leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. The operating lease ROU asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. Variable lease payments are expensed as incurred and are not included within the ROU asset and lease liability calculation. Variable lease payments primarily include reimbursements of costs incurred by lessors for common area maintenance and utilities. The Company's lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. The Company rents or subleases certain real estate under agreements that are classified as operating leases. Leases with an initial term of 12 months or less are not recorded on the balance sheet. The Company recognizes lease expense for these leases on a straight-line basis over the lease term. The Company does not account for lease components (e.g., fixed payments including rent) separately from the non-lease components (e.g., common-area maintenance costs). Adoption of Topic 842 The primary impact for the Company was the balance sheet recognition of operating lease ROU asset and operating lease liabilities. In addition, the Company's financing lease obligations that historically did not qualify for sale leaseback accounting under ASC 840-40, “Leases - Sale-Leaseback Transactions” (“ASC 840-40”) now meet the criteria for sale under Topic 842 and are recorded as operating leases. As a result, the Company reclassified financing liabilities of $198.3 million from accrued expenses and long-term financing lease obligations and assets of $174.6 million from property, plant and equipment, net, to $23.8 million accumulated deficit adjustment reflecting the cumulative effect of an accounting change related to the sale-leasebacks. The following table summarizes the impacts of adopting Topic 842 on the Company's condensed consolidated balance sheet as of December 29, 2018 (in thousands): As Reported Balance as of December 29, 2018 Adjustments due to Topic 842 As Adjusted Balance as of December 29, 2018 Assets Property, plant and equipment, net $ 342,820 $ (174,386 ) $ 168,434 Operating lease right-of-use assets $ — $ 78,855 $ 78,855 Other non-current assets $ 14,849 $ (4,884 ) $ 9,965 Liabilities Accrued expenses and other current liabilities $ 131,891 $ (7,343 ) $ 124,548 Long-term financing lease obligation $ 193,538 $ (193,538 ) $ — Other long-term liabilities $ 68,082 $ (4,907 ) $ 63,175 Operating lease liabilities - short-term $ — $ 19,209 $ 19,209 Operating lease liabilities - long-term $ — $ 62,467 $ 62,467 Equity Accumulated deficit $ 956,970 $ (23,697 ) $ 933,273 The Company has operating leases for real estate and automobiles. During the three months ended March 30, 2019, operating lease expense was approximately $16.2 million (including $10.2 million of accelerated rent expense due to restructuring resulting in abandonment of lease facilities). Variable lease cost, short-term lease cost and sublease income were immaterial during the three months ended March 30, 2019. The following table presents maturity of lease liabilities under our non-cancelable operating leases as of March 30, 2019 (in thousands): Remainder of 2019 $ 18,190 2020 21,047 2021 13,663 2022 11,409 2023 8,984 Thereafter 29,033 Total lease payments (1) $ 102,326 Less: interest (2) 24,137 Present value of lease liabilities $ 78,189 (1) Operating lease payments exclude $3.2 million of legally binding minimum lease payments for leases signed but not yet commenced. (2) Calculated using the interest rate for each lease. The following table presents supplemental information for the three months ended March 30, 2019 (in thousands, except for weighted average): Weighted average remaining lease term 5.1 years Weighted average discount rate 8.6 % Cash paid for amounts included in the measurement of lease liabilities $ 6,471 Operating cash flow from operating leases $ 6,471 Leased assets obtained in exchange for new operating lease liabilities $ 1,666 In addition, the Company has operating leases for office space that had not commenced as of March 30, 2019. The legally binding minimum lease payments for these leases is $3.2 million . The term of these leases is three years . ASC 840-40 Disclosures The following table presents future minimum lease payments related to the non-cancelable portion of operating leases as of December 29, 2018 (in thousands): 2019 2020 2021 2022 2023 Thereafter Total Operating lease payments $ 18,352 $ 14,047 $ 7,888 $ 5,926 $ 4,905 $ 18,303 $ 69,421 Financing Lease Obligations The Company evaluated two sale-leaseback transactions that were executed by Coriant in the past and assumed by the Company in the Acquisition (as defined in Note 7, "Business Combination" to the Notes to Condensed Consolidated Financial Statements). It was determined that these transactions did not qualify for sale-leaseback accounting under ASC 840-40. The Company leases a facility (land and all attached real property) in Naperville, Illinois that was sold to a third party and subsequently leased back. This was determined to be a failed sale-leaseback due to a $31.5 million imposition reimbursement payment to be made over 10 years , which was linked to the total building income generated each year. As a result of purchase accounting, the financing lease obligation was recorded at the present value of the remaining lease payments and expected value of the facility at the end of the occupancy period. The financing lease obligation will continue to be amortized over the remaining period of the lease term. The assets will continue to be depreciated over their remaining useful lives under ASC 840-40. Additionally, the Company leases a facility (land and all attached real property) in Finland, which was sold to a third party and subsequently leased back. The lease was determined to be a failed sale-leaseback due to the deposit being considered a form of collateral. The amount of the deposit was equal to one year of rental payments, whereas typical deposits are approximately two to three months of rental payments. As a result of purchase accounting, the financing lease obligation was recorded at the present value of the remaining lease payments and expected value of the facility at the end of the occupancy period. The financing lease obligation will continue to be amortized over the remaining period of the lease term under ASC 840-40. The assets will continue to be depreciated over their remaining useful lives. In the first quarter of 2019, in conjunction with the adoption of the new lease accounting standard, the transactions qualified for sale-leaseback accounting under Topic 842, as control of the underlying assets was transferred to the lessor. As such, the balances of fixed assets, accrued expenses and other long-term liabilities as of the transition date related to the Naperville, Illinois and Finland leases were reclassified to accumulated deficit as a cumulative effect of an accounting change.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Mar. 30, 2019
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting Pronouncements Recently Adopted In August 2018, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update No. 2018-15, “Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract” (“ASU 2018-15”). The update provides guidance for determining if a cloud computing arrangement is within the scope of internal-use software guidance, and would require capitalization of certain implementation costs. The Company adopted ASU 2018-15 in the first quarter of 2019. The Company's adoption of ASU 2018-15 did not have a significant impact on its consolidated financial statements. In June 2018, the FASB issued Accounting Standards Update No. 2018-07, “Improvements to Non-employee Share-Based Payment Accounting” (“ASU 2018-07”), which simplifies the accounting for share-based payments granted to non-employees for goods and services. Under ASU 2018-07, certain guidance on such payments to non-employees is aligned with the requirements for share-based payments granted to employees. The Company's adoption of ASU 2017-09 during its first quarter of 2019 did not have a significant impact on its consolidated financial statements. In February 2016, the FASB issued Topic 842, 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. The Company adopted Topic 842 in the first quarter of 2019 utilizing the modified retrospective transition method through a cumulative-effect adjustment at the beginning of the first quarter of 2019. The Company elected the package of practical expedients permitted under the transition guidance, which allowed the Company to carryforward its historical lease classification, assessment on whether a contract was or contains a lease, and initial direct costs for leases that existed prior to December 30, 2018. The Company also elected to combine its lease and non-lease components and not recognize right-of-use (“ROU”) assets and lease liabilities for leases with an initial term of 12 months or less. The Company did not elect to apply the hindsight practical expedient when determining lease term and assessing impairment of ROU assets. Accounting Pronouncements Not Yet Effective In August 2018, the FASB issued Accounting Standards Update No. 2018-14, “Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans” (“ASU 2018-14”). The update eliminates, adds, and modifies certain disclosure requirements for employers that sponsor defined benefit pension or other post-retirement plans. ASU 2018-14 is effective for the Company in its first quarter of 2020, with early adoption permitted. The Company is currently evaluating the impact the adoption of ASU 2018-14 will have on its consolidated financial statements. In August 2018, the FASB issued Accounting Standards Update No. 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement” (“ASU 2018-13”). The update eliminates, adds, and modifies certain disclosure requirements for fair value measurements. ASU 2018-13 is effective for the Company in its first quarter of 2020 and early adoption is permitted of the entire standard or only the provisions that eliminate or modify disclosure requirements. The Company is currently evaluating the impact the adoption of ASU 2018-13 will have on its consolidated financial statements. In January 2017, the FASB issued Accounting Standards Update No. 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. In June 2016, the FASB issued Accounting Standards Update No. 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.

Revenue Recognition

Revenue Recognition	3 Months Ended
	Mar. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition Capitalization of Costs to Obtain a Contract T he ending balance of the Company’s capitalized costs to obtain a contract as of March 30, 2019 and December 29, 2018 were $0.3 million and $0.4 million , respectively. The Company's amortization expense was not material for the three months ended March 30, 2019 and March 31, 2018. Disaggregation of Revenue The following table presents the Company's revenue disaggregated by revenue source (in thousands): Three Months Ended March 30, March 31, Product $ 223,007 $ 171,629 Services 69,700 31,052 Total revenue $ 292,707 $ 202,681 The Company sells its products directly to customers who are predominantly service providers and to channel partners that sell on its behalf. The following tables present the Company's revenue disaggregated by geography, based on the shipping address of the customer and by sales channel (in thousands): Three Months Ended March 30, March 31, United States $ 132,522 $ 129,025 Other Americas 15,132 5,215 Europe, Middle East and Africa 98,992 59,199 Asia Pacific 46,061 9,242 Total revenue $ 292,707 $ 202,681 Three Months Ended March 30, March 31, Direct $ 248,196 $ 188,462 Indirect 44,511 14,219 Total revenue $ 292,707 $ 202,681 Contract Balances The following table provides information about receivables, contract assets and contract liabilities from contracts with customers (in thousands): March 30, December 29, 2018 Accounts receivable, net $ 267,117 $ 317,115 Contract assets $ 18,837 $ 24,981 Deferred revenue $ 126,071 $ 120,302 Revenue recognized for the three months ended March 30, 2019 that was included in the deferred revenue balance at the beginning of the reporting period was $36.8 million . Changes in the contract asset and liability balances during the three months ended March 30, 2019 were not materially impacted by other factors. Transaction Price Allocated to the Remaining Performance Obligation 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 2019 2020 2021 2022 2023 Thereafter Total Revenue expected to be recognized in the future as of March 30, 2019 $ 335,418 $ 78,284 $ 28,268 $ 5,436 $ 3,041 $ 1,148 $ 451,595

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 30, 2019
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 30, 2019 As of December 29, 2018 Fair Value Measured Using Fair Value Measured Using Level 1 Level 2 Total Level 1 Level 2 Total Assets Money market funds $ 904 $ — $ 904 $ 10,347 $ — $ 10,347 Corporate bonds — 16,022 16,022 — 23,512 23,512 U.S. agency notes — — — — 2,999 2,999 U.S. treasuries — — — 23,987 — 23,987 Total assets $ 904 $ 16,022 $ 16,926 $ 34,334 $ 26,511 $ 60,845 Liabilities Foreign currency exchange forward contracts $ — $ (30 ) $ (30 ) $ — $ (91 ) $ (91 ) During the three months ended March 30, 2019 , there were no transfers of assets or liabilities between Level 1 and Level 2 of the fair value hierarchy. As of March 30, 2019 and December 29, 2018 , none of the Company’s existing securities were classified as Level 3 securities. The Company classifies certain facilities-related charges within Level 3 of the fair value hierarchy and applies fair value accounting on a nonrecurring basis when impairment indicators exist or upon the existence of observable fair values. The fair values are classified as Level 3 measurements due to the significance of unobservable inputs. These analyses require management to make assumptions and estimates regarding industry and economic factors, future operating results and discount rates. 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 2017 Restructuring 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 first half of 2018, the Company revised the estimates to its facilities-related accruals. See Note 10, “Restructuring and Related Costs” to the Notes to Condensed Consolidated Financial Statements for more information. Cash, Cash Equivalents and Investments Cash, cash equivalents and investments were as follows (in thousands): March 30, 2019 Adjusted Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash $ 166,355 $ — $ — $ 166,355 Money market funds 904 — — 904 Total cash and cash equivalents $ 167,259 $ — $ — $ 167,259 Corporate bonds 16,048 — (26 ) 16,022 Total short-term investments $ 16,048 $ — $ (26 ) $ 16,022 Total cash, cash equivalents and investments $ 183,307 $ — $ (26 ) $ 183,281 December 29, 2018 Adjusted Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash $ 168,620 $ — $ — $ 168,620 Money market funds 10,347 — — 10,347 U.S. treasuries 23,986 1 — 23,987 Total cash and cash equivalents $ 202,953 $ 1 $ — $ 202,954 Corporate bonds 23,603 — (91 ) 23,512 U.S. agency notes 3,000 — (1 ) 2,999 Total short-term investments $ 26,603 $ — $ (92 ) $ 26,511 Total cash, cash equivalents and investments $ 229,556 $ 1 $ (92 ) $ 229,465 As of March 30, 2019 , the Company’s available-for-sale investments have contractual maturity terms of up to 6 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 30, 2019 , the Company had $183.3 million of cash, cash equivalents and short-term investments, including $70.2 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.

Business Combination

Business Combination	3 Months Ended
	Mar. 30, 2019
Business Combinations [Abstract]
Business Combination	Business Combination On October 1, 2018 (the “Acquisition Date”), the Company completed the acquisition of all the outstanding limited liability company interests of Telecom Holding Parent LLC (“Coriant”), a Delaware limited liability company (the “Acquisition”). The Acquisition positions the Company as one of the largest providers of vertically integrated transport networking solutions in the world, enhances the Company's ability to serve a global customer base and accelerates delivery of the innovative solutions its customers demand. This Acquisition also positions the Company to expand the breadth of customer applications it can address, including metro aggregation and switching, disaggregated transport and routing, and software-enabled multi-layer network management and control. The Acquisition was accounted for under the acquisition method of accounting in accordance with ASC Topic 805, “Business Combinations” and consisted of the following (in thousands): Cash (1) $ 154,192 Equity consideration (2) 129,628 Total $ 283,820 (1) Cash consideration of $154.2 million includes $10.0 million that the Company held in escrow as of December 29, 2018. (2) Based on the closing price of the Company's common stock of $6.18 on October 1, 2018, the $129.6 million equity consideration represents the fair value of approximately 21 million shares of the Company's common stock issued to Coriant shareholders in accordance with the Purchase Agreement. The Company financed the cash portion of the purchase price of the Acquisition with the net proceeds from its offering of $402.5 million in aggregate principal amount of its 2.125% convertible senior notes due September 1, 2024 (the “2024 Notes”). See Note 13, “Debt” to the Notes to Condensed Consolidated Financial Statements for more information regarding the 2024 Notes. The Company allocated the fair value of the purchase price of the Acquisition to the tangible and intangible assets acquired as well as liabilities assumed, based on their estimated fair values. The excess of the purchase price over the fair values of these identifiable assets and liabilities was recorded as goodwill. The Company prepared an initial determination of the fair value of assets acquired and liabilities assumed as of the Acquisition Date using preliminary information. In accordance with Accounting Standards Codification 805, "Business Combinations," during the measurement period an acquirer retrospectively adjusts the provisional amounts recognized at the Acquisition Date to reflect information obtained about facts and circumstances that existed as of the Acquisition Date that, if known, would have affected the measurement of the amounts recognized as of the Acquisition Date. Accordingly, the Company has recognized measurement period adjustments made during the first quarter of 2019 to the fair value of certain assets acquired and liabilities assumed as a result of additional information obtained. None of the adjustments had a material impact on the Company's financial results. The following table summarizes the Company’s preliminary allocation of the purchase consideration based on the fair value of assets acquired and liabilities assumed at the Acquisition Date (in thousands): Amounts Recognized as of Acquisition Date Measurement Period Adjustments Total Cash and cash equivalents $ 15,549 $ — $ 15,549 Restricted cash 25,743 — 25,743 Accounts receivable 170,466 — 170,466 Inventory 96,067 — 96,067 Property, plant and equipment, net 217,991 — 217,991 Other assets 39,145 — 39,145 Intangible assets, net 200,700 — 200,700 Goodwill 48,235 503 48,738 Financing lease obligation (194,700 ) — (194,700 ) Deferred revenue (43,502 ) 211 (43,291 ) Other liabilities (291,874 ) (714 ) (292,588 ) Total net assets $ 283,820 $ — $ 283,820 The Company expects to finalize the allocation of the purchase consideration as soon as practicable, pending finalization of income taxes and any other adjustments related to acquired assets or liabilities, but no later than 12 months from the Acquisition Date. The following table presents details of the identifiable assets acquired at the Acquisition Date (in thousands, except estimated useful life): Fair Value Estimated Useful Life (In Years) Customer relationships and backlog $ 111,400 8 Developed technology 70,550 5 In-process technology 17,750 n/a Trade name 1,000 1 Total $ 200,700 Goodwill generated from this business combination is primarily attributable to the synergies from combining the operations of Coriant with that of the Company, which resulted in strengthening the Company's ability to serve a global customer base and accelerate delivery of product solutions. The goodwill recorded in the Acquisition is not expected to be deductible for income tax purposes.

Derivative Instruments

Derivative Instruments	3 Months Ended
	Mar. 30, 2019
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 periodically 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. For the three months ended March 30, 2019 and March 31, 2018 , the before-tax effect of the foreign currency exchange forward contracts was a net gain of $0.7 million and a loss $0.6 million , respectively. In each of these periods, the impact of the gross gains and losses was offset by foreign exchange rate fluctuations on the underlying foreign currency denominated amounts. As of March 30, 2019 , 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 30, 2019 As of December 29, 2018 Gross Notional (1) Other Accrued Liabilities Gross Notional (1) Other Accrued Liabilities Foreign currency exchange forward contracts Related to euro denominated receivables $ 41,242 $ (30 ) $ 40,068 $ (52 ) Related to British pound denominated receivables $ — — $ 6,412 (38 ) Related to euro denominated restricted cash $ 236 — $ 240 (1 ) $ (30 ) $ (91 ) (1) Represents the face amounts of forward contracts that were outstanding as of the end of the period noted. Accounts Receivable Factoring The Company sells certain designated trade account receivables based on factoring arrangements to a large international banking institution. Pursuant to the terms of the arrangements, the Company accounts for these transactions in accordance with ASC 860, “Transfers and Servicing.” The Company's factor purchases trade accounts receivables on a non-recourse basis and without any further obligations. Trade accounts receivables balances sold are removed from the consolidated balance sheets and cash received are reflected as cash provided by operating activities in the consolidated statements of cash flow. The difference between the fair value of the Company's trade receivables and the proceeds received is recorded as interest expense in the Company's condensed consolidated statements of operations, and for the three months ended March 30, 2019, the Company's recognized factoring related interest expense was approximately $0.2 million . The gross amount of trade accounts receivables sold for the three months ended March 30, 2019, totaled approximately $24.4 million . The Company did not enter into any factoring arrangements during the three months ended March 31, 2018.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	3 Months Ended
	Mar. 30, 2019
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 30, 2019 (in thousands): Balance as of December 29, 2018 $ 227,231 Adjustment to goodwill acquired 503 Foreign currency translation adjustments (6,217 ) Balance as of March 30, 2019 $ 221,517 The gross carrying amount of goodwill may change due to the effects of foreign currency fluctuations as a portion of these assets are denominated in foreign currency. 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 30, 2019 and December 29, 2018 (in thousands, except for weighted average): March 30, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Useful Life (In Years) Intangible assets with finite lives: Trade names $ 1,000 $ (500 ) $ 500 NMF* Customer relationships 156,486 (48,453 ) 108,033 3.5 Developed technology 163,024 (73,343 ) 89,681 1.6 Total intangible assets with finite lives $ 320,510 $ (122,296 ) $ 198,214 5.1 In-process technology 17,750 — 17,750 Total intangible assets $ 338,260 $ (122,296 ) $ 215,964 December 29, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Useful Life (In Years) Intangible assets with finite lives: Trade names $ 1,000 $ (250 ) $ 750 NMF* Customer relationships 158,110 (42,478 ) 115,632 3.5 Developed technology 166,355 (67,368 ) 98,987 1.7 Total intangible assets with finite lives $ 325,465 $ (110,096 ) $ 215,369 5.2 In-process technology 17,750 — 17,750 Total intangible assets $ 343,215 $ (110,096 ) $ 233,119 *NMF = Not meaningful 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 a portion of these assets are denominated in foreign currency. Amortization expense was $15.3 million for the three months ended March 30, 2019 and was $6.9 million for the corresponding period in 2018. Intangible assets are carried at cost less accumulated amortization. Amortization expenses are recorded to the appropriate cost and expense categories. The following table summarizes the Company’s estimated future amortization expense of intangible assets with finite lives as of March 30, 2019 (in thousands): Fiscal Years Total Remainder of 2019 2020 2021 2022 2023 2024 and Thereafter Total future amortization expense $ 198,214 $ 44,554 $ 42,096 $ 29,558 $ 27,031 $ 21,131 $ 33,844

Balance Sheet Details

Balance Sheet Details	3 Months Ended
	Mar. 30, 2019
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, the Company's restricted cash balance includes amounts pledged as collateral on its derivative instruments. The following table provides details of selected balance sheet items (in thousands): March 30 December 29 Inventory Raw materials $ 82,528 $ 74,435 Work in process 63,004 57,232 Finished goods 186,963 180,221 Total inventory $ 332,495 $ 311,888 Property, plant and equipment, net Computer hardware $ 16,556 $ 15,633 Computer software (1) 35,752 40,923 Laboratory and manufacturing equipment 305,866 304,889 Land and building 12,352 187,184 Furniture and fixtures 2,601 2,587 Leasehold and building improvements 44,956 46,038 Construction in progress 38,579 32,997 Subtotal $ 456,662 $ 630,251 Less accumulated depreciation and amortization (295,516 ) (287,431 ) Total property, plant and equipment, net $ 161,146 $ 342,820 Accrued expenses and other current liabilities Loss contingency related to non-cancelable purchase commitments $ 26,458 $ 26,042 Professional and other consulting fees 9,046 10,442 Taxes payable 19,643 23,249 Accrued rebate and customer prepay liability 14,453 14,301 Restructuring accrual 30,977 13,097 Acquisition related funds in escrow — 10,000 Short-term financing lease obligation — 4,718 Short-term operating lease liability 18,240 — Other accrued expenses and other current liabilities 22,270 30,042 Total accrued expenses $ 141,087 $ 131,891 (1) Included in computer software at March 30, 2019 and December 29, 2018 were $14.6 million and $13.1 million , respectively, related to enterprise resource planning ( “ ERP ” ) systems that the Company implemented. The unamortized ERP costs at March 30, 2019 and December 29, 2018 were $4.8 million and $3.9 million , respectively.

Restructuring and Related Costs

Restructuring and Related Costs	3 Months Ended
	Mar. 30, 2019
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	Restructuring and Related Costs In December of 2018, the Company implemented a restructuring initiative (the “2018 Restructuring Plan”) as part of a comprehensive review of the Company's operations and ongoing integration activities in order to optimize resources for future growth, improve efficiencies and address redundancies following the Acquisition. As part of the 2018 Restructuring Plan, the Company hopes to reduce expenses, streamline the organization, and eliminate fixed costs to align more closely with its needs going forward. The Company expects to incur additional restructuring during 2019 as it progresses with the 2018 Restructuring Plan. The Company expects to substantially complete activities under the 2018 Restructuring Plan by the end of 2019. 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. The following table presents restructuring and other related costs included in cost of revenue and operating expenses in the accompanying consolidated statements of operations under the 2018 Restructuring Plan, Coriant's previous restructuring and reorganization plans, and the 2017 Restructuring Plan (in thousands): Three Months Ended March 30, 2019 Cost of Revenue Operating Expenses Severance and related expenses $ 20,698 $ 5,850 Accelerated amortization of lease assets due to cease use — 11,338 Asset impairment 768 — Total $ 21,466 $ 17,188 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, operating lease liabilities and other long-term liabilities in the accompanying condensed consolidated balance sheets (in thousands): December 29, 2018 Charges Cash Non-cash Settlements and Other March 30, Severance and related expenses $ 19,842 $ 26,548 $ (6,203 ) $ (1,356 ) $ 38,831 Accelerated amortization of lease assets due to cease use 11,338 (11,338 ) — Facilities 4,266 — — (4,266 ) — Asset impairment 243 768 (140 ) (768 ) 103 Total $ 24,351 $ 38,654 $ (6,343 ) $ (17,728 ) $ 38,934 As of March 30, 2019, the Company's restructuring liability was comprised of $38.8 million severance and related expenses, primarily due to the planned closure of the Company's Berlin, Germany manufacturing facility, which is being transitioned to a third-party manufacturer. The Company has committed funding from a third party to cover the costs associated with the planned closure of this facility.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	3 Months Ended
	Mar. 30, 2019
Equity [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Accumulated other comprehensive loss includes certain changes in equity that are excluded from net loss. The following table sets forth the changes in accumulated other comprehensive income (loss) by component for the three months ended March 30, 2019 (in thousands): Unrealized Loss on Other Available-for-Sale Securities Foreign Currency Translation Accumulated Tax Effect Actuarial Gain (Loss) on Pension Total Balance at December 29, 2018 $ (91 ) $ (18,932 ) $ (964 ) $ (5,313 ) $ (25,300 ) Net current-period other comprehensive income (loss) 65 (5,557 ) — 78 (5,414 ) Balance at March 30, 2019 $ (26 ) $ (24,489 ) $ (964 ) $ (5,235 ) $ (30,714 )

Basic and Diluted Net Loss Per

Basic and Diluted Net Loss Per Common Share	3 Months Ended
	Mar. 30, 2019
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 by the weighted average number of common shares outstanding during the period. Diluted net loss per common share is computed using net loss 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 restricted stock units (“RSUs”) and performance stock units (“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 2024 Notes from the conversion spread (as further discussed in Note 13, “Debt” to the Notes to Condensed Consolidated Financial Statements). The Company would include the dilutive effects of the 2024 Notes in the calculation of diluted net income per common share if the average market price is above the conversion price. Upon conversion of the 2024 Notes, it is the Company’s intention to pay cash equal to the lesser of the aggregate principal amount or the conversion value of the 2024 Notes being converted, therefore, only the conversion spread relating to the 2024 Notes would be included in the Company’s diluted earnings per share calculation unless their effect is anti-dilutive. The Company includes the common shares underlying PSUs in the calculation of diluted net income per common 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 30, March 31, Net loss $ (121,601 ) $ (26,280 ) Weighted average common shares outstanding - basic and diluted 176,406 150,333 Net loss per common share - basic and diluted $ (0.69 ) $ (0.17 ) The Company incurred net losses during the three months ended March 30, 2019 and March 31, 2018, and as a result, potential common shares from stock options, RSUs, PSUs and the assumed release of outstanding shares under the ESPP were not included in the diluted shares used to calculate net loss per share, as their inclusion would have been anti-dilutive. Additionally, due to the net loss position during these periods, the Company excluded the potential shares issuable upon conversion of the 2024 Notes and the $150.0 million in aggregate principal amount of its 1.75% convertible senior notes due June 1, 2018 (the “2018 Notes”) in the calculation of diluted earnings 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 30, March 31, Stock options 970 1,187 RSUs 12,473 9,439 PSUs 2,599 1,545 ESPP shares 1,325 2,247 Total 17,367 14,418

Debt

Debt	3 Months Ended
	Mar. 30, 2019
Debt Disclosure [Abstract]
Debt	Debt Mortgage Payable In March 2019, the Company mortgaged a property it owns. The Company received proceeds of $8.7 million in connection with the loan. The loan carries a fixed interest rate of 5.25% and is repayable in 59 equal monthly installments of approximately $0.1 million each with the remaining unpaid principal balance plus accrued unpaid interest due five years from the date of the loan. Payments commenced in April 2019. As of March 30, 2019, no payments had been made and the entire balance of $8.7 million remained outstanding, of which $0.4 million was included in accrued expenses and other current liabilities and $8.3 million was included in long-term debt. 2.125% Convertible Senior Notes due September 1, 2024 In September 2018, the Company issued the 2024 Notes due on September 1, 2024, unless earlier repurchased, redeemed or converted. The 2024 Notes are governed by a base indenture dated as of September 11, 2018 and a first supplemental indenture dated as of September 11, 2018 (together, the “Indenture”), between the Company and U.S. Bank National Association, as trustee. The 2024 Notes are unsecured, and the Indenture does 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 the Company's other securities by the Company. Interest is payable semi-annually in arrears on March 1 and September 1 of each year, which commenced on March 1, 2019. The net proceeds to the Company were approximately $391.4 million , of which approximately $48.9 million was used to pay the cost of the capped call transactions with certain financial institutions (“Capped Calls”). The Company also used a portion of the remaining net proceeds to fund the cash portion of the purchase price of the Acquisition, including fees and expenses relating thereto, and intends to use the remaining net proceeds for general corporate purposes. The Capped Calls have an initial strike price of $9.87 per share, subject to certain adjustments, which corresponds to the initial conversion price of the 2024 Notes. The Capped Calls have initial cap prices of $15.19 per share, subject to certain adjustments. The Capped Calls cover, subject to anti-dilution adjustments, 40.8 million shares of common stock. The capped call transactions are expected generally to reduce or offset potential dilution to the Company's common stock upon any conversion of the 2024 Notes and/or offset any cash payments the Company is required to make in excess of the principal amount of converted 2024 Notes, as the case may be, with such reduction and/or offset subject to a cap. The Capped Calls expire on various dates between July 5, 2024 and August 29, 2024. The Capped Calls were recorded as a reduction of the Company’s stockholders’ equity in the accompanying condensed consolidated balance sheets. 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 2024 Notes. For any remaining conversion obligation, the Company intends to pay or deliver, as the case may be, either cash, shares of its common stock, or a combination of cash and shares of its common stock, at the Company’s election. The initial conversion rate is 101.2812 shares of common stock per $1,000 principal amount of 2024 Notes, subject to anti-dilution adjustments, which is equivalent to a conversion price of approximately $9.87 per share of common stock. Throughout the term of the 2024 Notes, the conversion rate may be adjusted upon the occurrence of certain events, including for any cash dividends. Holders of the 2024 Notes will not receive any cash payment representing accrued and unpaid interest upon conversion of a 2024 Note. Accrued but unpaid interest will be deemed to be paid in full upon conversion rather than canceled, extinguished or forfeited. Prior to June 1, 2024, holders may convert their 2024 Notes under the following circumstances: • during any fiscal quarter commencing after the fiscal quarter ended on December 29, 2018 (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 2024 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; • if the Company calls the 2024 Notes for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date; • 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 June 1, 2024 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their 2024 Notes at any time, regardless of the foregoing circumstances. If the Company undergoes a fundamental change as defined in the Indenture governing the 2024 Notes, holders may require the Company to repurchase for cash all or any portion of their 2024 Notes at a repurchase price equal to 100% of the principal amount of the 2024 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, be required to increase the conversion rate by a number of additional shares for a holder that elects to convert its 2024 Notes in connection with such make-whole fundamental change. The net carrying amounts of the debt obligation were as follows (in thousands): March 30, December 29, 2018 Principal $ 402,500 $ 402,500 Unamortized discount (1) (123,023 ) (127,264 ) Unamortized issuance cost (1) (8,030 ) (8,307 ) Net carrying amount $ 271,447 $ 266,929 (1) Unamortized debt conversion discount and issuance costs will be amortized over the remaining life of the 2024 Notes, which is approximately 66 months . As of March 30, 2019, the carrying amount of the equity component of the 2024 Notes was $128.7 million . In accounting for the issuance of the 2024 Notes, the Company separated the 2024 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 2024 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 2024 Notes. The Company allocated the total issuance costs incurred to the liability and equity components of the 2024 Notes based on their relative values. Issuance costs attributable to the liability component were recorded as a reduction to the liability portion of the 2024 Notes and will be amortized as interest expense over the term of the 2024 Notes. The issuance costs attributable to the equity component were netted with the equity component in stockholders’ equity. The Company recorded a deferred tax liability of $30.9 million in connection with the issuance of the 2024 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 2024 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 stockholders’ equity if freestanding. The following table sets forth total interest expense recognized related to the 2024 Notes (in thousands): Three Months Ended March 30, 2019 Contractual interest expense $ 2,138 Amortization of debt issuance costs 277 Amortization of debt discount 4,241 Total interest expense $ 6,656 For the three months ended March 30, 2019, the debt discount and debt issuance costs were amortized, using an annual effective interest rate of 10.07% , to interest expense over the term of the 2024 Notes. As of March 30, 2019, the fair value of the 2024 Notes was $318.0 million . The fair value was determined based on the quoted bid price of the 2024 Notes in an over-the-counter market on March 29, 2019. The 2024 Notes are classified as Level 2 of the fair value hierarchy. Based on the closing price of the Company’s common stock of $4.34 on March 29, 2019 (last trading day of the fiscal quarter), the if-converted value of the 2024 Notes did not exceed their principal amount. 1.75% Convertible Senior Notes due June 1, 2018 In May 2013, the Company issued the 2018 Notes, which matured on June 1, 2018. Upon maturity of the 2018 Notes, the Company repaid in full all $150.0 million in aggregate principal amount and the final coupon interest of $1.3 million . The following table sets forth total interest expense recognized related to the 2018 Notes (in thousands): Three Months Ended March 31, 2018 Contractual interest expense $ 656 Amortization of debt issuance costs 239 Amortization of debt discount 2,779 Total interest expense $ 3,674 The coupon rate was 1.75% . For the three months ended March 31, 2018 , 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 2018 Notes.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 30, 2019
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. As of March 30, 2019 , the Company has reserved a total of 15.4 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 29, 2018 1,115 $ 8.09 $ — Stock options granted — $ — Stock options exercised — $ — $ — Stock options canceled (145 ) $ 7.05 Outstanding at March 30, 2019 970 $ 8.24 $ — Exercisable at March 30, 2019 970 $ 8.24 $ — Number of Restricted Stock Units Weighted Average Grant Date Fair Value Per Share Aggregate Intrinsic Value Outstanding at December 29, 2018 6,746 $ 10.83 $ 26,446 RSUs granted 6,236 $ 4.33 RSUs released (139 ) $ 11.20 $ 669 RSUs canceled (370 ) $ 11.15 Outstanding at March 30, 2019 12,473 $ 7.56 $ 54,132 Number of Performance Stock Units Weighted Average Grant Date Fair Value Per Share Aggregate Intrinsic Value Outstanding at December 29, 2018 1,129 $ 16.10 $ 4,425 PSUs granted 1,650 $ 4.15 PSUs released — $ — $ — PSUs canceled (180 ) $ 16.50 Outstanding at March 30, 2019 2,599 $ 8.15 $ 11,280 Expected to vest at March 30, 2019 1,666 $ 7,230 The aggregate intrinsic value of unexercised stock options is calculated as the difference between the closing price of the Company’s common stock of $4.34 at March 29, 2019 (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 $4.34 at March 29, 2019 (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 30, 2019 . 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 $ 70,848 2.35 PSUs $ 11,322 1.72 Employee Stock Options The Company did not grant any stock options during the three months ended March 30, 2019 . Amortization of stock-based compensation related to stock options in the three months ended March 30, 2019 and the corresponding period in 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 30, 2019 March 31, 2018 Volatility 72% 62% Risk-free interest rate 2.48% 1.90% Expected life 0.5 years 0.5 years Estimated fair value $1.77 $3.13 Total stock-based compensation expense $1,316 $1,555 Restricted Stock Units During the three months ended March 30, 2019 , the Company granted RSUs to employees and members of the Company's board of directors representing the right to receive 6.2 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 30, 2019 and the corresponding period of 2018 was approximately $6.0 million and $7.4 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 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 2017 and the first half 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 SPGIIPTR, as well as the assumptions used in calculating these values were based on estimates as follows: 2018 2017 2016 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 PSUs granted to the Company's executive officers and senior management under the 2016 Plan during the first quarter of 2019 are based on performance criteria related to a specific financial target over the span of a three year performance period. These PSUs may become eligible for vesting before the end of the three year performance period if the applicable financial target is met. The number of shares to be issued upon vesting of these PSUs are capped at one time the target number of PSUs granted. In addition, one of the Company's executive officers was awarded a PSU that will be eligible to vest if the market price condition is met. The following table summarizes by grant year, the Company’s PSU activity for the three months ended March 30, 2019 (in thousands): Grant Year Total Number of Performance Stock Units 2016 2017 2018 2019 Outstanding at December 29, 2018 1,129 210 481 437 — PSUs granted 1,650 — — — 1,650 PSUs released — — — — — PSUs canceled (180 ) (156 ) (11 ) (13 ) — Outstanding at March 30, 2019 2,599 54 470 424 1,650 Amortization of stock-based compensation related to PSUs in the three months ended March 30, 2019 and the corresponding period of 2018 was approximately $1.7 million and $2.1 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 30, December 29, Stock-based compensation effects in inventory $ 5,094 $ 4,750 Three Months Ended March 30, March 31, Stock-based compensation effects included in net loss before income taxes Cost of revenue $ 538 $ (122 ) Research and development 3,603 4,324 Sales and marketing 1,547 2,898 General and administration 2,235 2,767 $ 7,923 $ 9,867 Cost of revenue – amortization from balance sheet (1) 790 1,116 Total stock-based compensation expense $ 8,713 $ 10,983 (1) Stock-based compensation expense deferred to inventory in prior periods and recognized in the current period.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income taxes for the three months ended March 30, 2019 were a tax expense of $0.2 million on pre-tax losses of $121.4 million . This compared to a tax benefit of $0.7 million on a pre-tax loss of $27.0 million for the three months ended March 31, 2018. Provision for income taxes increased by approximately $0.9 million during the three months ended March 30, 2019 as a result of additional foreign tax expense from including the entities from the Acquisition. The tax expense and benefit projected in the Company's effective tax rate primarily represents foreign taxes of the Company's overseas profitable subsidiaries, as well as results of the Company's Swedish operations, inclusive of purchase accounting amortization and other charges for the three months ended March 31, 2019. 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 30, 2019, 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.

Segment Information

Segment Information	3 Months Ended
	Mar. 30, 2019
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 30, December 29, 2018 United States $ 120,113 $ 288,614 Other Americas 2,730 2,370 Europe, Middle East and Africa 26,099 38,273 Asia Pacific 12,204 13,563 Total property, plant and equipment, net $ 161,146 $ 342,820 For information regarding revenue disaggregated by geography, see Note 4, “Revenue Recognition” to the Notes to Condensed Consolidated Financial Statements.

Guarantees

Guarantees	3 Months Ended
	Mar. 30, 2019
Guarantees [Abstract]
Guarantees	Guarantees Product Warranties Activity related to product warranty was as follows (in thousands): Three Months Ended March 30, 2019 March 31, 2018 Beginning balance $ 41,021 $ 30,909 Charges to operations 5,420 4,357 Utilization (5,803 ) (4,438 ) Change in estimate (1) (887 ) 20 Balance at the end of the period $ 39,751 $ 30,848 (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. Letters of Credit and Bank Guarantees The Company had $28.9 million of standby letters of credit and bank guarantees outstanding as of March 30, 2019 that consisted of $23.0 million related to customer performance guarantees, $1.4 million related to value added tax and customs' licenses, $2.7 million related to property leases, $1.2 million related to restructuring plans, $0.5 million related to credit cards and $0.2 million related to suppliers. The Company had $30.0 million of standby letters of credit and bank guarantees outstanding as of December 29, 2018 . These consisted of $23.4 million related to customer performance guarantees, $1.4 million related to a value added tax license, $2.9 million related to property leases, $1.8 million related to Coriant's pre-Acquisition restructuring plans and $0.5 million related to credit cards. As of March 30, 2019 and December 29, 2018 , the Company had a line of credit for approximately $1.6 million to support the issuance of letters of credit, of which zero been issued and outstanding for both periods. The Company has pledged approximately $4.8 million and $4.9 million of assets of a subsidiary to secure this line of credit and other obligations as of March 30, 2019 and December 29, 2018 , respectively.

Pension and Post-Retirement Ben

Pension and Post-Retirement Benefit Plans	3 Months Ended
	Mar. 30, 2019
Retirement Benefits [Abstract]
Pension and Post-Retirement Benefit Plans	Pension and Post-Retirement Benefit Plans As a result of the Acquisition, the Company acquired a number of post-employment plans in Germany, as well as a number of smaller post-employment plans in other countries, including both defined contribution and defined benefit plans. The defined benefit plans expose the Company to actuarial risks such as, investment risk, interest rate risk, life expectancy risk and salary risk. The characteristics of the defined benefit plans and the risks associated with them vary depending on legal, fiscal and economic requirements. Components of Net Periodic Benefit Cost Net periodic benefit cost for the Company's pension and other post-retirement benefit plans for the three months ended March 30, 2019 consisted of the following (in thousands): Service cost $ 356 Interest cost 371 Expected return on plan assets (604 ) Amortization of actuarial loss 418 Total net periodic benefit cost $ 541 Actuarial gains and losses are amortized using a corridor approach. The gain/loss corridor is equal to 10% of the greater of the pension benefit obligation and the market-related value of assets. Gains and losses in excess of the corridor are generally amortized over the average future working lifetime of the pension plan participants. All components of net periodic benefit cost are recorded in operating expense of the Company's condensed consolidated statements of operations.

Litigation and Contingencies

Litigation and Contingencies	3 Months Ended
	Mar. 30, 2019
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 infringement of U.S. Patent Nos. 6,469,816, 6,476,952, 6,594,055, 7,099,592, 7,620,327 (the “’327 patent”), 8,374,511 (the “‘511 patent”) and 8,913,898 (the “’898 patent”) (collectively, the “Oyster Optics patents in suit”). The complaint seeks unspecified damages and a permanent injunction. The Company filed its answer to Oyster Optics' complaint on February 3, 2017. The Company filed two petitions for Inter Partes Review (“IPR”) of the '898 patent with the U.S Patent and Trademark Office ("USPTO"). Other defendants have filed IPR petitions in connection with the remaining Oyster Optics patents in suit. The USPTO instituted two IPRs of the ‘511 patent and two IPRs of the ‘898 patent but denied IPR petitions in connection with the ‘327 patent. A Markman decision was issued on December 5, 2017 and fact discovery closed on December 22, 2017. Oyster Optics dropped the ‘511 and ‘898 patents, leaving only a few claims in the ‘327 patent at issue in the case. On May 15, 2018, Oyster Optics filed a new patent infringement complaint in the United States District Court for the Eastern District of Texas, naming the Company as a defendant. In its new complaint, Oyster Optics alleges infringement of the ‘327 patent, U.S. Patent No. 9,749,040 and the ‘898 patent. On June 8, 2018, the court granted the parties’ joint motion to sever and consolidate the first-filed lawsuit with the later filed case. The Company filed its answer to the new complaint on July 16, 2018. A case management conference was held on September 11, 2018, and the court set a trial date for November 4, 2019. On October 26, 2018, the Company filed an amended answer to include a license defense. On November 29, 2018, the Company filed a motion for summary judgment based on the license defense. The court issued a second Markman decision on May 3, 2019, in which the parties were ordered to schedule a mediation within 30 days of the decision. 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 infringement of 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 held on May 9, 2018 and the court has set a trial for March 2019. On June 14, 2018, the Company filed a petition for IPR of the Core Optical patent in suit in the USPTO. Core Optical contacted the Company on July 19, 2018 to propose that the case be stayed pending the IPR. The Company agreed to Core Optical’s proposal, and the parties filed a joint motion to stay, which the court granted on July 31, 2018. On October 17, 2018, Core Optical filed a response to the Company's IPR petition. On January 14, 2019, the USPTO denied the Company's IPR petition, and on February 13, 2019, the Company filed a request for rehearing in the USPTO requesting reconsideration of the dismissal of the Company's IPR petition. The parties participated in a mediation on March 15, 2019 and have agreed to a further mediation scheduled for late May 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. On June 8, 2017, a Civil Investigative Demand was issued to Coriant pursuant to a False Claims Act investigation by the U.S. government as to whether there has been any violation of 31 U.S.C. §3729. Coriant provided documents and other responses to the U.S. government, and the Company will continue to cooperate in the ongoing investigation. 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 30, 2019 and December 29, 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; and (ii) 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. 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. 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 Pronounceme_2

Recent Accounting Pronouncements (Policies)	3 Months Ended
	Mar. 30, 2019
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting Pronouncements Recently Adopted In August 2018, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update No. 2018-15, “Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract” (“ASU 2018-15”). The update provides guidance for determining if a cloud computing arrangement is within the scope of internal-use software guidance, and would require capitalization of certain implementation costs. The Company adopted ASU 2018-15 in the first quarter of 2019. The Company's adoption of ASU 2018-15 did not have a significant impact on its consolidated financial statements. In June 2018, the FASB issued Accounting Standards Update No. 2018-07, “Improvements to Non-employee Share-Based Payment Accounting” (“ASU 2018-07”), which simplifies the accounting for share-based payments granted to non-employees for goods and services. Under ASU 2018-07, certain guidance on such payments to non-employees is aligned with the requirements for share-based payments granted to employees. The Company's adoption of ASU 2017-09 during its first quarter of 2019 did not have a significant impact on its consolidated financial statements. In February 2016, the FASB issued Topic 842, 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. The Company adopted Topic 842 in the first quarter of 2019 utilizing the modified retrospective transition method through a cumulative-effect adjustment at the beginning of the first quarter of 2019. The Company elected the package of practical expedients permitted under the transition guidance, which allowed the Company to carryforward its historical lease classification, assessment on whether a contract was or contains a lease, and initial direct costs for leases that existed prior to December 30, 2018. The Company also elected to combine its lease and non-lease components and not recognize right-of-use (“ROU”) assets and lease liabilities for leases with an initial term of 12 months or less. The Company did not elect to apply the hindsight practical expedient when determining lease term and assessing impairment of ROU assets. Accounting Pronouncements Not Yet Effective In August 2018, the FASB issued Accounting Standards Update No. 2018-14, “Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans” (“ASU 2018-14”). The update eliminates, adds, and modifies certain disclosure requirements for employers that sponsor defined benefit pension or other post-retirement plans. ASU 2018-14 is effective for the Company in its first quarter of 2020, with early adoption permitted. The Company is currently evaluating the impact the adoption of ASU 2018-14 will have on its consolidated financial statements. In August 2018, the FASB issued Accounting Standards Update No. 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement” (“ASU 2018-13”). The update eliminates, adds, and modifies certain disclosure requirements for fair value measurements. ASU 2018-13 is effective for the Company in its first quarter of 2020 and early adoption is permitted of the entire standard or only the provisions that eliminate or modify disclosure requirements. The Company is currently evaluating the impact the adoption of ASU 2018-13 will have on its consolidated financial statements. In January 2017, the FASB issued Accounting Standards Update No. 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. In June 2016, the FASB issued Accounting Standards Update No. 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.

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 30, 2019
Accounting Policies [Abstract]
Schedule of Prior Period Adjustments	The following table shows reclassified amounts to conform to the current period's presentation: Three Months Ended March 31, 2018 Previously Reported Change in Presentation Reclassification Current Presentation Cost of revenue: Cost of product $ 107,665 $ (5,341 ) $ 102,324 Cost of services 12,831 — 12,831 Amortization of intangible assets (1) — 5,341 5,341 Restructuring and related 17 — 17 Total $ 120,513 $ — $ 120,513 Operating expenses: Research and development $ 58,681 $ — $ 58,681 Sales and marketing 30,492 (1,607 ) 28,885 General and administrative 17,836 — 17,836 Amortization of intangible assets (1) — 1,607 1,607 Restructuring and related (163 ) — (163 ) Total $ 106,846 $ — $ 106,846 (1) These lines were not previously reported in the consolidated statements of operations.

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 30, 2019
Leases [Abstract]
Schedule of New Accounting Pronouncements	The following table summarizes the impacts of adopting Topic 842 on the Company's condensed consolidated balance sheet as of December 29, 2018 (in thousands): As Reported Balance as of December 29, 2018 Adjustments due to Topic 842 As Adjusted Balance as of December 29, 2018 Assets Property, plant and equipment, net $ 342,820 $ (174,386 ) $ 168,434 Operating lease right-of-use assets $ — $ 78,855 $ 78,855 Other non-current assets $ 14,849 $ (4,884 ) $ 9,965 Liabilities Accrued expenses and other current liabilities $ 131,891 $ (7,343 ) $ 124,548 Long-term financing lease obligation $ 193,538 $ (193,538 ) $ — Other long-term liabilities $ 68,082 $ (4,907 ) $ 63,175 Operating lease liabilities - short-term $ — $ 19,209 $ 19,209 Operating lease liabilities - long-term $ — $ 62,467 $ 62,467 Equity Accumulated deficit $ 956,970 $ (23,697 ) $ 933,273
Lease costs	The following table presents supplemental information for the three months ended March 30, 2019 (in thousands, except for weighted average): Weighted average remaining lease term 5.1 years Weighted average discount rate 8.6 % Cash paid for amounts included in the measurement of lease liabilities $ 6,471 Operating cash flow from operating leases $ 6,471 Leased assets obtained in exchange for new operating lease liabilities $ 1,666
Operating lease liabilities	The following table presents maturity of lease liabilities under our non-cancelable operating leases as of March 30, 2019 (in thousands): Remainder of 2019 $ 18,190 2020 21,047 2021 13,663 2022 11,409 2023 8,984 Thereafter 29,033 Total lease payments (1) $ 102,326 Less: interest (2) 24,137 Present value of lease liabilities $ 78,189 (1) Operating lease payments exclude $3.2 million of legally binding minimum lease payments for leases signed but not yet commenced. (2) Calculated using the interest rate for each lease.
Schedule of Future Minimum Rental Payments for Operating Leases	The following table presents future minimum lease payments related to the non-cancelable portion of operating leases as of December 29, 2018 (in thousands): 2019 2020 2021 2022 2023 Thereafter Total Operating lease payments $ 18,352 $ 14,047 $ 7,888 $ 5,926 $ 4,905 $ 18,303 $ 69,421

Revenue Recognition (Tables)

Revenue Recognition (Tables)	3 Months Ended
	Mar. 30, 2019
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 30, March 31, Product $ 223,007 $ 171,629 Services 69,700 31,052 Total revenue $ 292,707 $ 202,681 The Company sells its products directly to customers who are predominantly service providers and to channel partners that sell on its behalf. The following tables present the Company's revenue disaggregated by geography, based on the shipping address of the customer and by sales channel (in thousands): Three Months Ended March 30, March 31, United States $ 132,522 $ 129,025 Other Americas 15,132 5,215 Europe, Middle East and Africa 98,992 59,199 Asia Pacific 46,061 9,242 Total revenue $ 292,707 $ 202,681 Three Months Ended March 30, March 31, Direct $ 248,196 $ 188,462 Indirect 44,511 14,219 Total revenue $ 292,707 $ 202,681
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 30, December 29, 2018 Accounts receivable, net $ 267,117 $ 317,115 Contract assets $ 18,837 $ 24,981 Deferred revenue $ 126,071 $ 120,302
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 2019 2020 2021 2022 2023 Thereafter Total Revenue expected to be recognized in the future as of March 30, 2019 $ 335,418 $ 78,284 $ 28,268 $ 5,436 $ 3,041 $ 1,148 $ 451,595

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 30, 2019
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 30, 2019 As of December 29, 2018 Fair Value Measured Using Fair Value Measured Using Level 1 Level 2 Total Level 1 Level 2 Total Assets Money market funds $ 904 $ — $ 904 $ 10,347 $ — $ 10,347 Corporate bonds — 16,022 16,022 — 23,512 23,512 U.S. agency notes — — — — 2,999 2,999 U.S. treasuries — — — 23,987 — 23,987 Total assets $ 904 $ 16,022 $ 16,926 $ 34,334 $ 26,511 $ 60,845 Liabilities Foreign currency exchange forward contracts $ — $ (30 ) $ (30 ) $ — $ (91 ) $ (91 )
Investments at Fair Value	Cash, cash equivalents and investments were as follows (in thousands): March 30, 2019 Adjusted Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash $ 166,355 $ — $ — $ 166,355 Money market funds 904 — — 904 Total cash and cash equivalents $ 167,259 $ — $ — $ 167,259 Corporate bonds 16,048 — (26 ) 16,022 Total short-term investments $ 16,048 $ — $ (26 ) $ 16,022 Total cash, cash equivalents and investments $ 183,307 $ — $ (26 ) $ 183,281 December 29, 2018 Adjusted Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash $ 168,620 $ — $ — $ 168,620 Money market funds 10,347 — — 10,347 U.S. treasuries 23,986 1 — 23,987 Total cash and cash equivalents $ 202,953 $ 1 $ — $ 202,954 Corporate bonds 23,603 — (91 ) 23,512 U.S. agency notes 3,000 — (1 ) 2,999 Total short-term investments $ 26,603 $ — $ (92 ) $ 26,511 Total cash, cash equivalents and investments $ 229,556 $ 1 $ (92 ) $ 229,465

Business Combination (Tables)

Business Combination (Tables)	3 Months Ended
	Mar. 30, 2019
Business Combinations [Abstract]
Schedule of business acquisitions	The Acquisition was accounted for under the acquisition method of accounting in accordance with ASC Topic 805, “Business Combinations” and consisted of the following (in thousands): Cash (1) $ 154,192 Equity consideration (2) 129,628 Total $ 283,820 (1) Cash consideration of $154.2 million includes $10.0 million that the Company held in escrow as of December 29, 2018. (2) Based on the closing price of the Company's common stock of $6.18 on October 1, 2018, the $129.6 million equity consideration represents the fair value of approximately 21 million shares of the Company's common stock issued to Coriant shareholders in accordance with the Purchase Agreement.
Schedule of Assets Acquired and Liabilities Assumed	The following table summarizes the Company’s preliminary allocation of the purchase consideration based on the fair value of assets acquired and liabilities assumed at the Acquisition Date (in thousands): Amounts Recognized as of Acquisition Date Measurement Period Adjustments Total Cash and cash equivalents $ 15,549 $ — $ 15,549 Restricted cash 25,743 — 25,743 Accounts receivable 170,466 — 170,466 Inventory 96,067 — 96,067 Property, plant and equipment, net 217,991 — 217,991 Other assets 39,145 — 39,145 Intangible assets, net 200,700 — 200,700 Goodwill 48,235 503 48,738 Financing lease obligation (194,700 ) — (194,700 ) Deferred revenue (43,502 ) 211 (43,291 ) Other liabilities (291,874 ) (714 ) (292,588 ) Total net assets $ 283,820 $ — $ 283,820
Schedule of Intangible Assets Acquired	The following table presents details of the identifiable assets acquired at the Acquisition Date (in thousands, except estimated useful life): Fair Value Estimated Useful Life (In Years) Customer relationships and backlog $ 111,400 8 Developed technology 70,550 5 In-process technology 17,750 n/a Trade name 1,000 1 Total $ 200,700

Derivative Instruments (Tables)

Derivative Instruments (Tables)	3 Months Ended
	Mar. 30, 2019
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 30, 2019 As of December 29, 2018 Gross Notional (1) Other Accrued Liabilities Gross Notional (1) Other Accrued Liabilities Foreign currency exchange forward contracts Related to euro denominated receivables $ 41,242 $ (30 ) $ 40,068 $ (52 ) Related to British pound denominated receivables $ — — $ 6,412 (38 ) Related to euro denominated restricted cash $ 236 — $ 240 (1 ) $ (30 ) $ (91 ) (1) Represents the face amounts of forward contracts that were outstanding as of the end of the period noted.

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	3 Months Ended
	Mar. 30, 2019
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 30, 2019 (in thousands): Balance as of December 29, 2018 $ 227,231 Adjustment to goodwill acquired 503 Foreign currency translation adjustments (6,217 ) Balance as of March 30, 2019 $ 221,517
Schedule of Finite-Lived Intangible Assets	The following tables present details of the Company’s intangible assets as of March 30, 2019 and December 29, 2018 (in thousands, except for weighted average): March 30, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Useful Life (In Years) Intangible assets with finite lives: Trade names $ 1,000 $ (500 ) $ 500 NMF* Customer relationships 156,486 (48,453 ) 108,033 3.5 Developed technology 163,024 (73,343 ) 89,681 1.6 Total intangible assets with finite lives $ 320,510 $ (122,296 ) $ 198,214 5.1 In-process technology 17,750 — 17,750 Total intangible assets $ 338,260 $ (122,296 ) $ 215,964 December 29, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Useful Life (In Years) Intangible assets with finite lives: Trade names $ 1,000 $ (250 ) $ 750 NMF* Customer relationships 158,110 (42,478 ) 115,632 3.5 Developed technology 166,355 (67,368 ) 98,987 1.7 Total intangible assets with finite lives $ 325,465 $ (110,096 ) $ 215,369 5.2 In-process technology 17,750 — 17,750 Total intangible assets $ 343,215 $ (110,096 ) $ 233,119 *NMF = Not meaningful
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 30, 2019 (in thousands): Fiscal Years Total Remainder of 2019 2020 2021 2022 2023 2024 and Thereafter Total future amortization expense $ 198,214 $ 44,554 $ 42,096 $ 29,558 $ 27,031 $ 21,131 $ 33,844

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	3 Months Ended
	Mar. 30, 2019
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 30 December 29 Inventory Raw materials $ 82,528 $ 74,435 Work in process 63,004 57,232 Finished goods 186,963 180,221 Total inventory $ 332,495 $ 311,888 Property, plant and equipment, net Computer hardware $ 16,556 $ 15,633 Computer software (1) 35,752 40,923 Laboratory and manufacturing equipment 305,866 304,889 Land and building 12,352 187,184 Furniture and fixtures 2,601 2,587 Leasehold and building improvements 44,956 46,038 Construction in progress 38,579 32,997 Subtotal $ 456,662 $ 630,251 Less accumulated depreciation and amortization (295,516 ) (287,431 ) Total property, plant and equipment, net $ 161,146 $ 342,820 Accrued expenses and other current liabilities Loss contingency related to non-cancelable purchase commitments $ 26,458 $ 26,042 Professional and other consulting fees 9,046 10,442 Taxes payable 19,643 23,249 Accrued rebate and customer prepay liability 14,453 14,301 Restructuring accrual 30,977 13,097 Acquisition related funds in escrow — 10,000 Short-term financing lease obligation — 4,718 Short-term operating lease liability 18,240 — Other accrued expenses and other current liabilities 22,270 30,042 Total accrued expenses $ 141,087 $ 131,891 (1) Included in computer software at March 30, 2019 and December 29, 2018 were $14.6 million and $13.1 million , respectively, related to enterprise resource planning ( “ ERP ” ) systems that the Company implemented. The unamortized ERP costs at March 30, 2019 and December 29, 2018 were $4.8 million and $3.9 million , respectively.

Restructuring and Related Cos_2

Restructuring and Related Costs (Tables)	3 Months Ended
	Mar. 30, 2019
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	The following table presents restructuring and other related costs included in cost of revenue and operating expenses in the accompanying consolidated statements of operations under the 2018 Restructuring Plan, Coriant's previous restructuring and reorganization plans, and the 2017 Restructuring Plan (in thousands): Three Months Ended March 30, 2019 Cost of Revenue Operating Expenses Severance and related expenses $ 20,698 $ 5,850 Accelerated amortization of lease assets due to cease use — 11,338 Asset impairment 768 — Total $ 21,466 $ 17,188 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, operating lease liabilities and other long-term liabilities in the accompanying condensed consolidated balance sheets (in thousands): December 29, 2018 Charges Cash Non-cash Settlements and Other March 30, Severance and related expenses $ 19,842 $ 26,548 $ (6,203 ) $ (1,356 ) $ 38,831 Accelerated amortization of lease assets due to cease use 11,338 (11,338 ) — Facilities 4,266 — — (4,266 ) — Asset impairment 243 768 (140 ) (768 ) 103 Total $ 24,351 $ 38,654 $ (6,343 ) $ (17,728 ) $ 38,934

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 30, 2019
Equity [Abstract]
Summary of Changes in Accumulated Other Comprehensive Income (Loss)	The following table sets forth the changes in accumulated other comprehensive income (loss) by component for the three months ended March 30, 2019 (in thousands): Unrealized Loss on Other Available-for-Sale Securities Foreign Currency Translation Accumulated Tax Effect Actuarial Gain (Loss) on Pension Total Balance at December 29, 2018 $ (91 ) $ (18,932 ) $ (964 ) $ (5,313 ) $ (25,300 ) Net current-period other comprehensive income (loss) 65 (5,557 ) — 78 (5,414 ) Balance at March 30, 2019 $ (26 ) $ (24,489 ) $ (964 ) $ (5,235 ) $ (30,714 )

Basic and Diluted Net Loss Pe_2

Basic and Diluted Net Loss Per Common Share (Tables)	3 Months Ended
	Mar. 30, 2019
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 30, March 31, Net loss $ (121,601 ) $ (26,280 ) Weighted average common shares outstanding - basic and diluted 176,406 150,333 Net loss per common share - basic and diluted $ (0.69 ) $ (0.17 )
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 30, March 31, Stock options 970 1,187 RSUs 12,473 9,439 PSUs 2,599 1,545 ESPP shares 1,325 2,247 Total 17,367 14,418

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 30, 2019
Debt Disclosure [Abstract]
Components of Convertible Senior Notes	The net carrying amounts of the debt obligation were as follows (in thousands): March 30, December 29, 2018 Principal $ 402,500 $ 402,500 Unamortized discount (1) (123,023 ) (127,264 ) Unamortized issuance cost (1) (8,030 ) (8,307 ) Net carrying amount $ 271,447 $ 266,929 (1) Unamortized debt conversion discount and issuance costs will be amortized over the remaining life of the 2024 Notes, which is approximately 66 months .
Interest Expense Recognized Related To Notes	The following table sets forth total interest expense recognized related to the 2018 Notes (in thousands): Three Months Ended March 31, 2018 Contractual interest expense $ 656 Amortization of debt issuance costs 239 Amortization of debt discount 2,779 Total interest expense $ 3,674 The following table sets forth total interest expense recognized related to the 2024 Notes (in thousands): Three Months Ended March 30, 2019 Contractual interest expense $ 2,138 Amortization of debt issuance costs 277 Amortization of debt discount 4,241 Total interest expense $ 6,656

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 30, 2019
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 29, 2018 1,115 $ 8.09 $ — Stock options granted — $ — Stock options exercised — $ — $ — Stock options canceled (145 ) $ 7.05 Outstanding at March 30, 2019 970 $ 8.24 $ — Exercisable at March 30, 2019 970 $ 8.24 $ —
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 29, 2018 6,746 $ 10.83 $ 26,446 RSUs granted 6,236 $ 4.33 RSUs released (139 ) $ 11.20 $ 669 RSUs canceled (370 ) $ 11.15 Outstanding at March 30, 2019 12,473 $ 7.56 $ 54,132
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 29, 2018 1,129 $ 16.10 $ 4,425 PSUs granted 1,650 $ 4.15 PSUs released — $ — $ — PSUs canceled (180 ) $ 16.50 Outstanding at March 30, 2019 2,599 $ 8.15 $ 11,280 Expected to vest at March 30, 2019 1,666 $ 7,230
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 30, 2019 . 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 $ 70,848 2.35 PSUs $ 11,322 1.72
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 30, 2019 March 31, 2018 Volatility 72% 62% Risk-free interest rate 2.48% 1.90% Expected life 0.5 years 0.5 years Estimated fair value $1.77 $3.13 Total stock-based compensation expense $1,316 $1,555
Schedule of Share-based Payment Award, Valuation Assumptions	The ranges of estimated values of the PSUs granted that are compared to the SPGIIPTR, as well as the assumptions used in calculating these values were based on estimates as follows: 2018 2017 2016 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 30, 2019 (in thousands): Grant Year Total Number of Performance Stock Units 2016 2017 2018 2019 Outstanding at December 29, 2018 1,129 210 481 437 — PSUs granted 1,650 — — — 1,650 PSUs released — — — — — PSUs canceled (180 ) (156 ) (11 ) (13 ) — Outstanding at March 30, 2019 2,599 54 470 424 1,650
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 30, December 29, Stock-based compensation effects in inventory $ 5,094 $ 4,750 Three Months Ended March 30, March 31, Stock-based compensation effects included in net loss before income taxes Cost of revenue $ 538 $ (122 ) Research and development 3,603 4,324 Sales and marketing 1,547 2,898 General and administration 2,235 2,767 $ 7,923 $ 9,867 Cost of revenue – amortization from balance sheet (1) 790 1,116 Total stock-based compensation expense $ 8,713 $ 10,983 (1) Stock-based compensation expense deferred to inventory in prior periods and recognized in the current period.

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 30, 2019
Segment Reporting [Abstract]
Table of Long Lived Assets	The following table sets forth long-lived assets by geographic region (in thousands): March 30, December 29, 2018 United States $ 120,113 $ 288,614 Other Americas 2,730 2,370 Europe, Middle East and Africa 26,099 38,273 Asia Pacific 12,204 13,563 Total property, plant and equipment, net $ 161,146 $ 342,820

Guarantees (Tables)

Guarantees (Tables)	3 Months Ended
	Mar. 30, 2019
Guarantees [Abstract]
Activity Related to Product Warranty	Activity related to product warranty was as follows (in thousands): Three Months Ended March 30, 2019 March 31, 2018 Beginning balance $ 41,021 $ 30,909 Charges to operations 5,420 4,357 Utilization (5,803 ) (4,438 ) Change in estimate (1) (887 ) 20 Balance at the end of the period $ 39,751 $ 30,848 (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.

Pension and Post-Retirement B_2

Pension and Post-Retirement Benefit Plans (Tables)	3 Months Ended
	Mar. 30, 2019
Retirement Benefits [Abstract]
Schedule of Net Benefit Costs	Net periodic benefit cost for the Company's pension and other post-retirement benefit plans for the three months ended March 30, 2019 consisted of the following (in thousands): Service cost $ 356 Interest cost 371 Expected return on plan assets (604 ) Amortization of actuarial loss 418 Total net periodic benefit cost $ 541

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies - Restatement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Cost of revenue:
Amortization of intangible assets	$ 8,252	$ 5,341
Restructuring and related	21,466	17
Total cost of revenue	226,275	120,513
Operating expenses:
Research and development	73,660	58,681
Sales and marketing	40,037	28,885
General and administrative	33,044	17,836
Amortization of intangible assets	7,057	1,607
Restructuring and related	17,188	(163)
Total operating expenses	178,120	106,846
Product
Cost of revenue:
Cost of revenue	157,817	102,324
Services
Cost of revenue:
Cost of revenue	$ 36,676	12,831
Previously Reported
Cost of revenue:
Restructuring and related		17
Total cost of revenue		120,513
Operating expenses:
Research and development		58,681
Sales and marketing		30,492
General and administrative		17,836
Restructuring and related		(163)
Total operating expenses		106,846
Previously Reported | Product
Cost of revenue:
Cost of revenue		107,665
Previously Reported | Services
Cost of revenue:
Cost of revenue		12,831
Change in Presentation Reclassification
Cost of revenue:
Amortization of intangible assets		5,341
Restructuring and related		0
Total cost of revenue		0
Operating expenses:
Research and development		0
Sales and marketing		(1,607)
General and administrative		0
Amortization of intangible assets		1,607
Restructuring and related		0
Total operating expenses		0
Change in Presentation Reclassification | Product
Cost of revenue:
Cost of revenue		(5,341)
Change in Presentation Reclassification | Services
Cost of revenue:
Cost of revenue		$ 0

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 30, 2019USD ($)transaction
Lessee, Lease, Description [Line Items]
Renewal term	5 years
Leases not yet commenced	$ 3.2
Leases not yet commenced, term	3 years
Rent expense	$ 16.2
Accelerated rent expense	$ 10.2
Number of sale lease back transactions | transaction	2
Reimbursement expense	$ 31.5
Reimbursement term	10 years
Minimum
Lessee, Lease, Description [Line Items]
Term of contract	1 year
Maximum
Lessee, Lease, Description [Line Items]
Term of contract	10 years

Basis of Presentation and Sig_4

Basis of Presentation and Significant Accounting Policies - Additional Information (Details) - Sales revenue, net - Customer concentration risk	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Customer One
Concentration Risk [Line Items]
Concentration risk	11.00%	29.00%
Customer Two
Concentration Risk [Line Items]
Concentration risk		11.00%

Leases - Topic 842 Adjustments

Leases - Topic 842 Adjustments (Details) - USD ($) $ in Thousands	Dec. 29, 2018	Mar. 30, 2019	Jan. 01, 2019	Mar. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative-effect adjustment from adoption of ASU		$ 23,697		$ 15,406
Property, plant and equipment, net	$ 342,820	161,146	$ 168,434
Operating lease right-of-use assets		65,598	78,855
Other non-current assets	14,849	11,975	9,965
Accrued expenses and other current liabilities	131,891	141,087	124,548
Long-term financing lease obligation	193,538	0	0
Other long-term liabilities	68,082	63,826	63,175
Operating lease liabilities - short-term	0	18,240	19,209
Operating lease liabilities - long-term	0	59,949	62,467
Accumulated deficit	956,970	1,054,874	$ 933,273
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing liabilities	198,300
Decrease in property, plant and equipment	174,600
Property, plant and equipment, net	(174,386)
Operating lease right-of-use assets	78,855
Other non-current assets	(4,884)
Accrued expenses and other current liabilities	(7,343)
Long-term financing lease obligation	(193,538)
Other long-term liabilities	(4,907)
Operating lease liabilities - short-term	19,209
Operating lease liabilities - long-term	62,467
Accumulated deficit	(23,697)
Accumulated Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative-effect adjustment from adoption of ASU		$ 23,697		$ 15,406
Accumulated Deficit | ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative-effect adjustment from adoption of ASU	$ 23,800

Leases - Operating Lease Maturi

Leases - Operating Lease Maturity (Details) $ in Thousands	Mar. 30, 2019USD ($)
Leases [Abstract]
Remainder of 2019	$ 18,190
2020	21,047
2021	13,663
2022	11,409
2023	8,984
2024	29,033
Total lease payments	102,326
Less: interest	24,137
Present value of lease liabilities	$ 78,189

Leases - Lease Costs (Details)

Leases - Lease Costs (Details) $ in Thousands	3 Months Ended
	Mar. 30, 2019USD ($)
Leases [Abstract]
Weighted average remaining lease term	5 years 1 month
Weighted average discount rate	8.60%
Operating cash flow from operating leases	$ 6,471
Leased assets obtained in exchange for new operating lease liabilities	$ 1,666

Leases - Payments Under Topic 8

Leases - Payments Under Topic 840 (Details) $ in Thousands	Dec. 29, 2018USD ($)
Leases [Abstract]
2019	$ 18,352
2020	14,047
2021	7,888
2022	5,926
2023	4,905
Thereafter	18,303
Total	$ 69,421

Revenue Recognition - Narrative

Revenue Recognition - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 30, 2019	Dec. 29, 2018
Revenue from Contract with Customer [Abstract]
Capitalized cost to obtain contract	$ 0.3	$ 0.4
Deferred revenue recognized	$ 36.8

Revenue Recognition - Disaggreg

Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenue	$ 292,707	$ 202,681
United States
Disaggregation of Revenue [Line Items]
Total revenue	132,522	129,025
Other Americas
Disaggregation of Revenue [Line Items]
Total revenue	15,132	5,215
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenue	98,992	59,199
Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenue	46,061	9,242
Product
Disaggregation of Revenue [Line Items]
Revenue	223,007	171,629
Services
Disaggregation of Revenue [Line Items]
Revenue	69,700	31,052
Direct
Disaggregation of Revenue [Line Items]
Total revenue	248,196	188,462
Indirect
Disaggregation of Revenue [Line Items]
Total revenue	$ 44,511	$ 14,219

Revenue Recognition - Contract

Revenue Recognition - Contract with Customer, Asset and Liability (Details) - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 29, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Accounts receivable, net	$ 267,117	$ 317,115	$ 317,115
Contract assets	18,837		24,981
Deferred revenue	$ 126,071		$ 120,302

Revenue Recognition - Revenue,

Revenue Recognition - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Details) $ in Thousands	Mar. 30, 2019USD ($)
Revenue from Contract with Customer [Abstract]
Revenue expected to be recognized in the future as of March 30, 2019	$ 451,595
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Revenue from Contract with Customer [Abstract]
Revenue expected to be recognized in the future as of March 30, 2019	$ 335,418
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized in the future, period	9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue from Contract with Customer [Abstract]
Revenue expected to be recognized in the future as of March 30, 2019	$ 78,284
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized in the future, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue from Contract with Customer [Abstract]
Revenue expected to be recognized in the future as of March 30, 2019	$ 28,268
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized in the future, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue from Contract with Customer [Abstract]
Revenue expected to be recognized in the future as of March 30, 2019	$ 5,436
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized in the future, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue from Contract with Customer [Abstract]
Revenue expected to be recognized in the future as of March 30, 2019	$ 3,041
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized in the future, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue from Contract with Customer [Abstract]
Revenue expected to be recognized in the future as of March 30, 2019	$ 1,148
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized in the future, period

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. 30, 2019	Dec. 29, 2018
Assets
Total assets	$ 16,926	$ 60,845
Money market funds
Assets
Total assets	904	10,347
Corporate bonds
Assets
Total assets	16,022	23,512
U.S. agency notes
Assets
Total assets	0	2,999
U.S. treasuries
Assets
Total assets	0	23,987
Level 1
Assets
Total assets	904	34,334
Level 1 | Money market funds
Assets
Total assets	904	10,347
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	0	23,987
Level 2
Assets
Total assets	16,022	26,511
Level 2 | Money market funds
Assets
Total assets	0	0
Level 2 | Corporate bonds
Assets
Total assets	16,022	23,512
Level 2 | U.S. agency notes
Assets
Total assets	0	2,999
Level 2 | U.S. treasuries
Assets
Total assets	0	0
Foreign currency exchange forward contracts
Liabilities
Foreign currency exchange forward contracts	(30)	(91)
Foreign currency exchange forward contracts | Level 1
Liabilities
Foreign currency exchange forward contracts	0	0
Foreign currency exchange forward contracts | Level 2
Liabilities
Foreign currency exchange forward contracts	$ (30)	$ (91)

Fair Value Measurements - Inves

Fair Value Measurements - Investments at Fair Value (Details) - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 29, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Cash	$ 166,355	$ 168,620
Adjusted Amortized Cost	183,307	229,556
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(26)	(92)
Fair Value	183,281	229,465
Cash and Cash Equivalents
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Adjusted Amortized Cost	167,259	202,953
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	0
Fair Value	167,259	202,954
Cash and Cash Equivalents | Money market funds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Adjusted Amortized Cost	904	10,347
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	904	10,347
Cash and Cash Equivalents | U.S. treasuries
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Adjusted Amortized Cost		23,986
Gross Unrealized Gains		1
Gross Unrealized Losses		0
Fair Value		23,987
Short-term Investments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Adjusted Amortized Cost	16,048	26,603
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(26)	(92)
Fair Value	16,022	26,511
Short-term Investments | Corporate bonds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Adjusted Amortized Cost	16,048	23,603
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(26)	(91)
Fair Value	$ 16,022	23,512
Short-term Investments | U.S. agency notes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Adjusted Amortized Cost		3,000
Gross Unrealized Gains		0
Gross Unrealized Losses		(1)
Fair Value		$ 2,999

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018	Dec. 30, 2017	Dec. 29, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	6 months
Cash, cash equivalents and short-term investments	$ 183,300
Cash and cash equivalents held by foreign subsidiaries	167,259	$ 151,436		$ 202,954
Foreign Subsidiary
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents held by foreign subsidiaries	$ 70,200
Operating Expenses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Facilities		$ (1,084)	$ 7,300

Business Combination - Prelimin

Business Combination - Preliminary Purchase Consideration (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 01, 2018	Mar. 30, 2019	Dec. 29, 2018
Business Acquisition [Line Items]
Acquisition related funds in escrow		$ 0	$ 10,000
Telecom Holding Parent LLC
Business Acquisition [Line Items]
Cash	$ 154,192
Equity consideration	129,628
Total	$ 283,820
Acquisition related funds in escrow			$ 10,000
Common Stock | Telecom Holding Parent LLC
Business Acquisition [Line Items]
Share price (in dollars per share)	$ 6.18
Number of shares issued (in shares)	21,000,000

Derivative Instruments - Narrat

Derivative Instruments - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Derivative [Line Items]
Before-tax effect of foreign currency exchange forward contracts not designated as hedging instruments, gain (loss)	$ 700	$ (600)
Interest expense	7,563	$ 3,683
Trade Accounts Receivable
Derivative [Line Items]
Interest expense	200
Receivables sold	$ 24,400

Business Combination - Assets A

Business Combination - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 29, 2018	Oct. 01, 2018
Business Acquisition [Line Items]
Goodwill	$ 221,517	$ 227,231
Telecom Holding Parent LLC
Business Acquisition [Line Items]
Cash and cash equivalents	15,549		$ 15,549
Restricted cash	25,743		25,743
Accounts receivable	170,466		170,466
Inventory	96,067		96,067
Property, plant and equipment, net	217,991		217,991
Other assets	39,145		39,145
Intangible assets, net	200,700		200,700
Goodwill	48,738		48,235
Financing lease obligation	(194,700)		(194,700)
Deferred revenue	(43,291)		(43,502)
Other liabilities	(292,588)		(291,874)
Total net assets	283,820		$ 283,820
ASU 2017-01 | Telecom Holding Parent LLC
Business Acquisition [Line Items]
Goodwill	503
Deferred revenue	211
Other liabilities	$ (714)

Derivative Instruments - Fair V

Derivative Instruments - Fair Value of Derivative Instruments Not Designated as Hedging Activities (Details) - Not designated as hedging instrument - USD ($)	Mar. 30, 2019	Dec. 29, 2018
Derivative [Line Items]
Other Accrued Liabilities	$ (30,000)	$ (91,000)
Related to euro denominated receivables
Derivative [Line Items]
Gross Notional	41,242,000	40,068,000
Other Accrued Liabilities	(30,000)	(52,000)
Related to British pound denominated receivables
Derivative [Line Items]
Gross Notional	0	6,412,000
Other Accrued Liabilities	0	(38,000)
Related to euro denominated restricted cash
Derivative [Line Items]
Gross Notional	236,000	240,000
Other Accrued Liabilities	$ 0	$ (1,000)

Business Combination - Narrativ

Business Combination - Narrative (Details) - 2.125% Convertible Senior Notes Due September 1, 2024 - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 29, 2018
Business Acquisition [Line Items]
Principal amount	$ 402,500	$ 402,500
Debt instrument interest percentage	2.125%

Business Combination - Intangib

Business Combination - Intangible Assets Acquired (Details) - USD ($) $ in Thousands	Oct. 01, 2018	Mar. 30, 2019	Dec. 29, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life (Years)		5 years 1 month 6 days	5 years 2 months 12 days
Customer relationships and backlog
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life (Years)		3 years 6 months	3 years 6 months
Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life (Years)		1 year 7 months 6 days	1 year 8 months 12 days
Telecom Holding Parent LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Total	$ 200,700	$ 200,700
Telecom Holding Parent LLC | Customer relationships and backlog
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived assets	$ 111,400
Estimated Useful Life (Years)	8 years
Telecom Holding Parent LLC | Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived assets	$ 70,550
Estimated Useful Life (Years)	5 years
Telecom Holding Parent LLC | Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived assets	$ 1,000
Estimated Useful Life (Years)	1 year
In-process technology | Telecom Holding Parent LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Indefinite-lived assets	$ 17,750

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Goodwill Roll Forward (Details) $ in Thousands	3 Months Ended
	Mar. 30, 2019USD ($)
Goodwill [Roll Forward]
Balance as of December 29, 2018	$ 227,231
Adjustment to goodwill acquired	503
Foreign currency translation adjustments	(6,217)
Balance as of March 30, 2019	$ 221,517

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Purchased Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 30, 2019	Dec. 29, 2018
Intangible assets with finite lives:
Gross Carrying Amount	$ 320,510	$ 325,465
Accumulated Amortization	(122,296)	(110,096)
Net Carrying Amount	$ 198,214	$ 215,369
Weighted average remaining useful life (in years)	5 years 1 month 6 days	5 years 2 months 12 days
Gross Carrying Amount	$ 338,260	$ 343,215
Net Carrying Amount	215,964	233,119
Trade names
Intangible assets with finite lives:
Gross Carrying Amount	1,000	1,000
Accumulated Amortization	(500)	(250)
Net Carrying Amount	500	750
Customer relationships
Intangible assets with finite lives:
Gross Carrying Amount	156,486	158,110
Accumulated Amortization	(48,453)	(42,478)
Net Carrying Amount	$ 108,033	$ 115,632
Weighted average remaining useful life (in years)	3 years 6 months	3 years 6 months
Developed technology
Intangible assets with finite lives:
Gross Carrying Amount	$ 163,024	$ 166,355
Accumulated Amortization	(73,343)	(67,368)
Net Carrying Amount	$ 89,681	$ 98,987
Weighted average remaining useful life (in years)	1 year 7 months 6 days	1 year 8 months 12 days
In-process technology
Intangible assets with finite lives:
Gross Carrying Amount	$ 17,750	$ 17,750

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairment	$ 0
Amortization expense	$ 15,300	$ 6,900

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Future Amortization Expense (Details) - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 29, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Net Carrying Amount	$ 198,214	$ 215,369
Remainder of 2019	44,554
2020	42,096
2021	29,558
2022	27,031
2023	21,131
2024 and Thereafter	$ 33,844

Balance Sheet Details (Details)

Balance Sheet Details (Details) - USD ($) $ in Thousands	Mar. 30, 2019	Jan. 01, 2019	Dec. 29, 2018
Inventory
Raw materials	$ 82,528		$ 74,435
Work in process	63,004		57,232
Finished goods	186,963		180,221
Total inventory	332,495		311,888
Property, plant and equipment, net
Property, plant and equipment, gross	456,662		630,251
Less accumulated depreciation and amortization	(295,516)		(287,431)
Total property, plant and equipment, net	161,146	$ 168,434	342,820
Accrued expenses and other current liabilities
Loss contingency related to non-cancelable purchase commitments	26,458		26,042
Professional and other consulting fees	9,046		10,442
Taxes payable	19,643		23,249
Accrued rebate and customer prepay liability	14,453		14,301
Restructuring accrual	30,977		13,097
Acquisition related funds in escrow	0		10,000
Short-term financing lease obligation	0		4,718
Short-term operating lease liability	18,240	$ 19,209	0
Other accrued expenses and other current liabilities	22,270		30,042
Total accrued expenses	141,087		131,891
Computer hardware
Property, plant and equipment, net
Property, plant and equipment, gross	16,556		15,633
Computer software
Property, plant and equipment, net
Property, plant and equipment, gross	35,752		40,923
Laboratory and manufacturing equipment
Property, plant and equipment, net
Property, plant and equipment, gross	305,866		304,889
Land and building
Property, plant and equipment, net
Property, plant and equipment, gross	12,352		187,184
Furniture and fixtures
Property, plant and equipment, net
Property, plant and equipment, gross	2,601		2,587
Leasehold and building improvements
Property, plant and equipment, net
Property, plant and equipment, gross	44,956		46,038
Construction in progress
Property, plant and equipment, net
Property, plant and equipment, gross	38,579		32,997
Enterprise resource planning systems
Property, plant and equipment, net
Property, plant and equipment, gross	14,600		13,100
Total property, plant and equipment, net	$ 4,800		$ 3,900

Restructuring and Related Cos_3

Restructuring and Related Costs - Restructuring and Other Related Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018	Dec. 30, 2017
Restructuring Cost and Reserve [Line Items]
Total	$ 38,654
Cost of Revenue
Restructuring Cost and Reserve [Line Items]
Severance and related expenses	20,698	$ 17
Accelerated amortization of lease assets due to cease use	0
Facilities		0
Asset impairment	768	0
Total	21,466	17
Operating Expenses
Restructuring Cost and Reserve [Line Items]
Severance and related expenses	5,850	945
Accelerated amortization of lease assets due to cease use	11,338
Facilities		(1,084)	$ 7,300
Asset impairment	0	(24)
Total	$ 17,188	$ (163)

Restructuring and Related Cos_4

Restructuring and Related Costs - Schedule of Restructuring Reserve by Type of Cost (Details) $ in Thousands	3 Months Ended
	Mar. 30, 2019USD ($)
Restructuring Reserve [Roll Forward]
Beginning balance	$ 24,351
Charges	38,654
Cash	(6,343)
Non-cash Settlements and Other	(17,728)
Ending balance	38,934
Severance and related expenses
Restructuring Reserve [Roll Forward]
Beginning balance	19,842
Charges	26,548
Cash	(6,203)
Non-cash Settlements and Other	(1,356)
Ending balance	38,831
Accelerated amortization of lease assets due to cease use
Restructuring Reserve [Roll Forward]
Charges	11,338
Non-cash Settlements and Other	(11,338)
Ending balance	0
Facilities
Restructuring Reserve [Roll Forward]
Beginning balance	4,266
Charges	0
Cash	0
Non-cash Settlements and Other	(4,266)
Ending balance	0
Asset impairment
Restructuring Reserve [Roll Forward]
Beginning balance	243
Charges	768
Cash	(140)
Non-cash Settlements and Other	(768)
Ending balance	$ 103

Restructuring and Related Cos_5

Restructuring and Related Costs - Narrative (Details) - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 29, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring liability	$ 38,934	$ 24,351
Severance and related expenses
Restructuring Cost and Reserve [Line Items]
Restructuring liability	$ 38,831	$ 19,842

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss (Details) $ in Thousands	3 Months Ended
	Mar. 30, 2019USD ($)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ (964)
Beginning balance	703,821
Net current-period other comprehensive loss	0
Ending balance	(964)
Ending balance	617,299
Unrealized Loss on Other Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(91)
Net current-period other comprehensive loss	65
Ending balance	(26)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(18,932)
Net current-period other comprehensive loss	(5,557)
Ending balance	(24,489)
Actuarial Gain (Loss) on Pension
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(5,313)
Net current-period other comprehensive loss	78
Ending balance	(5,235)
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(25,300)
Net current-period other comprehensive loss	(5,414)
Ending balance	$ (30,714)

Basic and Diluted Net Loss Pe_3

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. 30, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Net loss	$ (121,601)	$ (26,280)
Weighted average common shares outstanding - basic and diluted (in shares)	176,406	150,333
Net loss per common share - basic and diluted (in dollars per share)	$ (0.69)	$ (0.17)

Basic and Diluted Net Loss Pe_4

Basic and Diluted Net Loss Per Common Share - Antidilutive Shares (Details) - USD ($) shares in Thousands, $ in Millions	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share computation (in shares)	17,367	14,418
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share computation (in shares)	970	1,187
RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share computation (in shares)	12,473	9,439
PSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share computation (in shares)	2,599	1,545
ESPP shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share computation (in shares)	1,325	2,247
1.75% Convertible Senior Notes Due June 1, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Principal amount	$ 150
Debt instrument interest percentage	1.75%	1.75%

Debt - Narrative (Details)

Debt - Narrative (Details) $ / shares in Units, shares in Millions	Jun. 01, 2018USD ($)	Mar. 30, 2019USD ($)installment$ / sharesshares	Sep. 30, 2018USD ($)d	Mar. 30, 2019USD ($)installment$ / sharesshares	Mar. 31, 2018USD ($)	Mar. 29, 2019$ / shares	Dec. 29, 2018USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt outstanding in long term debt		$ 279,738,000		$ 279,738,000			$ 266,929,000
Proceeds from issuance of debt, net				$ 8,584,000	$ 0
Closing price of common stock (in usd per share) | $ / shares						$ 4.34
2.125% Convertible Senior Notes Due September 1, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt instrument interest percentage		2.125%		2.125%
Debt outstanding in long term debt		$ 271,447,000		$ 271,447,000			$ 266,929,000
Proceeds from issuance of debt, net			$ 391,400,000
Payment of capped call			$ 48,900,000
Strike price (in dollars per share) | $ / shares		$ 9.87		$ 9.87
Cap price (in dollars per share) | $ / shares		$ 15.19		$ 15.19
Number of shares covered by capped transactions (in shares) | shares		40.8		40.8
Conversion ratio			101.2812
Debt instrument, convertible, if-converted value in excess of principal			$ 1,000
Conversion price (in dollars per share) | $ / shares		$ 9.87		$ 9.87
Purchase price as a percentage on principal amount of the notes upon the occurrence of a fundamental change			100.00%
Net equity component carrying amount		$ 128,700,000		$ 128,700,000
Deferred tax liability		$ 30,900,000		$ 30,900,000
Additional effective rate of interest to be used on amortized carrying value		10.07%		10.07%
Fair value of convertible debt		$ 318,000,000		$ 318,000,000
2.125% Convertible Senior Notes, Circumstance 1
Accounts, Notes, Loans and Financing Receivable [Line Items]
Threshold trading days | d			20
Threshold consecutive trading days | d			30
Convertible threshold minimum percentage			130.00%
2.125% Convertible Senior Notes, Circumstance 2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt instrument, convertible, if-converted value in excess of principal			$ 1,000
Threshold trading days | d			5
Threshold consecutive trading days | d			5
Convertible, threshold maximum percentage			98.00%
1.75% Convertible Senior Notes Due June 1, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt instrument interest percentage		1.75%		1.75%	1.75%
Repayment of debt	$ 150,000,000
Additional effective rate of interest to be used on amortized carrying value					10.23%
Repayment of final coupon interest	$ 1,300,000
Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from debt		$ 8,700,000
Debt instrument interest percentage		5.25%		5.25%
Debt payment installments | installment		59		59
Debt payment		$ 100,000
Debt term		5 years
Debt outstanding		$ 8,700,000		$ 8,700,000
Debt outstanding in short term debt		400,000		400,000
Debt outstanding in long term debt		$ 8,300,000		$ 8,300,000

Debt - Components of Convertibl

Debt - Components of Convertible Senior Notes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Dec. 29, 2018
Debt Instrument [Line Items]
Net carrying amount	$ 279,738	$ 266,929
2.125% Convertible Senior Notes Due September 1, 2024
Debt Instrument [Line Items]
Principal amount	402,500	402,500
Unamortized discount	(123,023)	(127,264)
Unamortized issuance cost	(8,030)	(8,307)
Net carrying amount	$ 271,447	$ 266,929
Debt instrument term	66 months

Debt - Interest Expense Recogni

Debt - Interest Expense Recognized Related to Notes Prior to Capitalization of Interest (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
2.125% Convertible Senior Notes Due September 1, 2024
Debt Instrument [Line Items]
Contractual interest expense	$ 2,138
Amortization of debt issuance costs	277
Amortization of debt discount	4,241
Total interest expense	$ 6,656
1.75% Convertible Senior Notes Due June 1, 2018
Debt Instrument [Line Items]
Contractual interest expense		$ 656
Amortization of debt issuance costs		239
Amortization of debt discount		2,779
Total interest expense		$ 3,674

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 30, 2019USD ($)shares	Mar. 31, 2018USD ($)	Mar. 29, 2019$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing price of common stock (in usd per share) | $ / shares			$ 4.34
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units granted (in shares)	6,236
Amortization of stock-based compensation | $	$ 6	$ 7.4
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units granted (in shares)	1,650
Performance stock unit grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amortization of stock-based compensation | $	$ 1.7	$ 2.1
2016 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserved common stock for issuance of options (in shares)	15,400
2016 Plan maximum term	10 years
2016 Equity Incentive Plan | PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	3 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. 30, 2019USD ($)$ / sharesshares
Number of Stock Options
Stock options, beginning balance (in shares) | shares	1,115
Stock options, granted (in shares) | shares	0
Stock options, exercised (in shares) | shares	0
Stock options, canceled (in shares) | shares	(145)
Stock options, ending balance (in shares) | shares	970
Stock options, exercisable (in shares) | shares	970
Weighted-Average Exercise Price Per Share
Weighted-average exercise price per share, beginning balance (in usd per share) | $ / shares	$ 8.09
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	0
Weighted-average exercise price per share, options canceled (in usd per share) | $ / shares	7.05
Weighted-average exercise price per share, ending balance (in usd per share) | $ / shares	8.24
Average exercise price per share, exercisable (in usd per share) | $ / shares	$ 8.24
Aggregate Intrinsic Value
Aggregate intrinsic value, beginning balance | $	$ 0
Aggregate intrinsic value, options exercised | $	0
Aggregate intrinsic value, ending balance | $	0
Aggregate intrinsic value, exercisable | $	$ 0

Stockholders' Equity - Equity_2

Stockholders' Equity - Equity Award Activity - RSUs (Details) - Restricted stock units $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 30, 2019USD ($)$ / sharesshares
Number of Restricted Stock Units
Number of units, beginning balance (in shares) | shares	6,746
Number of units granted (in shares) | shares	6,236
Number of units released (in shares) | shares	(139)
Number units canceled (in shares) | shares	(370)
Number of units, ending balance (in shares) | shares	12,473
Weighted- Average Grant Date Fair Value Per Share
Weighted-average grant date fair value per share, beginning balance (in usd per share) | $ / shares	$ 10.83
Weighted-average grant date fair value per share, granted (in usd per share) | $ / shares	4.33
Weighted-average grant date fair value per share, released (in usd per share) | $ / shares	11.20
Weighted-average grant date fair value per share, canceled (in usd per share) | $ / shares	11.15
Weighted-average grant date fair value per share, ending balance (in usd per share) | $ / shares	$ 7.56
Aggregate Intrinsic Value
Aggregate intrinsic value, beginning balance | $	$ 26,446
Aggregate intrinsic value, RSUs released | $	669
Aggregate intrinsic value, ending balance | $	$ 54,132

Stockholders' Equity - Equity_3

Stockholders' Equity - Equity Award Activity - PSUs (Details) - PSUs $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 30, 2019USD ($)$ / sharesshares
Number of Performance Stock Units
Number of units, beginning balance (in shares)	1,129
Number of units granted (in shares)	1,650
Number of units released (in shares)	0
Number units canceled (in shares)	(180)
Number of units, ending balance (in shares)	2,599
Number of restricted stock units, expected to vest (in shares)	1,666
Weighted- Average Grant Date Fair Value Per Share
Weighted-average grant date fair value per share, beginning balance (in usd per share) | $ / shares	$ 16.10
Weighted-average grant date fair value per share, granted (in usd per share) | $ / shares	4.15
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	16.50
Weighted-average grant date fair value per share, ending balance (in usd per share) | $ / shares	$ 8.15
Aggregate Intrinsic Value
Aggregate intrinsic value, beginning balance | $	$ 4,425
Aggregate Intrinsic Value, PSUs released | $	0
Aggregate intrinsic value, ending balance | $	11,280
Aggregate intrinsic value, expected to vest | $	$ 7,230

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. 30, 2019USD ($)
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, net	$ 70,848
Weighted-average period	2 years 4 months 6 days
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, net	$ 11,322
Weighted-average period	1 year 8 months 19 days

Stockholders' Equity - Estimate

Stockholders' Equity - Estimated Fair Value of ESPP, Valuation Assumptions (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 8,713	$ 10,983
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility	72.00%	62.00%
Risk-free interest rate	2.48%	1.90%
Expected life	6 months	6 months
Estimated fair value (in usd per share)	$ 1.77	$ 3.13
Total stock-based compensation expense	$ 1,316	$ 1,555

Stockholders' Equity - Valuatio

Stockholders' Equity - Valuation Assumptions (Details) - PSUs	3 Months Ended
	Mar. 30, 2019$ / shares	Mar. 31, 2018$ / shares	Apr. 01, 2017$ / shares	Mar. 26, 2016$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Index volatility	33.00%			18.00%
Infinera volatility		58.00%		55.00%
Volatility minimum			55.00%
Volatility maximum		59.00%	56.00%
Estimated fair value (in dollars per share)	$ 4.15
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Index volatility			33.00%
Risk-free interest rate		2.37%	1.41%	0.95%
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%
Risk-free interest rate		2.40%	1.63%	1.07%
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. 30, 2019shares
Number of Performance Stock Units
Number of units, beginning balance (in shares)	1,129
Number of units granted (in shares)	1,650
Number of units released (in shares)	0
Number units canceled (in shares)	(180)
Number of units, ending balance (in shares)	2,599
2015
Number of Performance Stock Units
Number of units, beginning balance (in shares)	210
Number of units granted (in shares)	0
Number of units released (in shares)	0
Number units canceled (in shares)	(156)
Number of units, ending balance (in shares)	54
2016
Number of Performance Stock Units
Number of units, beginning balance (in shares)	481
Number of units granted (in shares)	0
Number of units released (in shares)	0
Number units canceled (in shares)	(11)
Number of units, ending balance (in shares)	470
2017
Number of Performance Stock Units
Number of units, beginning balance (in shares)	437
Number of units granted (in shares)	0
Number of units released (in shares)	0
Number units canceled (in shares)	(13)
Number of units, ending balance (in shares)	424
2018
Number of Performance Stock Units
Number of units, beginning balance (in shares)	0
Number of units granted (in shares)	1,650
Number of units released (in shares)	0
Number units canceled (in shares)	0
Number of units, ending balance (in shares)	1,650

Stockholders' Equity - Balance

Stockholders' Equity - Balance Sheet and Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018	Dec. 29, 2018
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	$ 7,923	$ 9,867
Cost of revenue – amortization from balance sheet	790	1,116
Total stock-based compensation expense	8,713	10,983
Cost of revenue
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	538	(122)
Research and development
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	3,603	4,324
Sales and marketing
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	1,547	2,898
General and administration
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	2,235	$ 2,767
Stock-based compensation effects in inventory
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects in inventory	$ 5,094		$ 4,750

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Provision (benefit) for income taxes	$ 193	$ (678)
Pre-tax loss	121,408	$ 26,958
Income tax benefit increase	$ 900

Segment Information (Details)

Segment Information (Details) $ in Thousands	3 Months Ended
	Mar. 30, 2019USD ($)segment	Dec. 29, 2018USD ($)
Segment Reporting [Abstract]
Number of business activities | segment	1
Number of reporting segments | segment	1
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property, plant and equipment, net	$ 161,146	$ 342,820
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property, plant and equipment, net	120,113	288,614
Other Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property, plant and equipment, net	2,730	2,370
Europe, Middle East and Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property, plant and equipment, net	26,099	38,273
Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property, plant and equipment, net	$ 12,204	$ 13,563

Guarantees - Activity Related t

Guarantees - Activity Related to Warranty (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Movement in Standard Product Warranty Accrual [Roll Forward]
Beginning balance	$ 41,021	$ 30,909
Charges to operations	5,420	4,357
Utilization	(5,803)	(4,438)
Change in estimate	(887)	20
Balance at the end of the period	$ 39,751	$ 30,848

Guarantees - Narrative (Details

Guarantees - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Dec. 29, 2018
Guarantor Obligations [Line Items]
Outstanding standby letters of credit	$ 28,900	$ 30,000
Restructuring plans	38,934	24,351
Debt instrument, collateral amount	4,800	4,900
Banker's guarantees or performance bonds
Guarantor Obligations [Line Items]
Line of credit facility, remaining borrowing capacity	1,600
Proceeds from lines of credit	0
Letter of credit
Guarantor Obligations [Line Items]
Customer performance guarantee	23,000	23,400
Value added tax license	1,400	1,400
Property leases	2,700	2,900
Restructuring plans	1,200
Pre-Acquisition restructuring plans		1,800
Credit cards	500	$ 500
Suppliers	$ 200

Pension and Post-Retirement B_3

Pension and Post-Retirement Benefit Plans - Components of Net Periodic Benefit Cost (Details) $ in Thousands	3 Months Ended
	Mar. 30, 2019USD ($)
Retirement Benefits [Abstract]
Service cost	$ 356
Interest cost	371
Expected return on plan assets	(604)
Amortization of actuarial loss	418
Total net periodic benefit cost	$ 541