Neophotonics (NPTN) 10-Q 7 May 20 2020 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2020	Apr. 30, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Transition Report	false
Entity File Number	001-35061
Entity Registrant Name	NeoPhotonics Corp
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-3253730
Entity Address, Address Line One	3081 Zanker Road
Entity Address, City or Town	San Jose
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95134
City Area Code	408
Local Phone Number	232-9200
Title of 12(b) Security	Common Stock, $0.0025 par value
Trading Symbol	NPTN
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		48,756,020
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001227025
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 90,905	$ 70,467
Short-term investments	7,662	7,638
Restricted cash	10,932	10,972
Accounts receivable, net of allowance for doubtful accounts	61,663	68,890
Inventories	46,146	46,930
Prepaid expenses and other current assets	26,178	25,851
Total current assets	243,486	230,748
Property, plant and equipment, net	76,293	81,133
Operating lease right-of-use assets	15,128	15,603
Purchased intangible assets, net	1,953	2,151
Goodwill	1,115	1,115
Other long-term assets	3,781	3,929
Total assets	341,756	334,679
Current liabilities:
Accounts payable	58,283	58,554
Current portion of long-term debt	3,066	3,044
Accrued and other current liabilities	48,710	47,481
Total current liabilities	110,059	109,079
Long-term Debt, Excluding Current Maturities	37,791	39,237
Operating lease liabilities, noncurrent	15,998	16,543
Other noncurrent liabilities	10,670	9,614
Total liabilities	174,518	174,473
Commitments and contingencies (Note 11)
Stockholders’ equity:
Preferred stock, $0.0025 par value, 10,000 shares authorized, no shares issued or outstanding	0	0
Common stock, $0.0025 par value, 100,000 shares authorized, As of March 31, 2020, 48,017 shares issued and outstanding; as of December 31, 2019, 48,256 shares issued and outstanding	122	121
Additional paid-in capital	585,198	582,504
Accumulated other comprehensive loss	(9,841)	(7,871)
Accumulated deficit	(408,241)	(414,548)
Total stockholders’ equity	167,238	160,206
Total liabilities and stockholders’ equity	$ 341,756	$ 334,679

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.0025	$ 0.0025
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0025	$ 0.0025
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	48,662,000	48,526,000
Common stock, shares outstanding (in shares)	48,662,000	48,526,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenue	$ 97,401	$ 79,366
Cost of goods sold	67,675	63,629
Gross profit	29,726	15,737
Operating expenses:
Research and development	11,884	14,683
Sales and marketing	3,659	4,603
General and administrative	6,789	7,753
Amortization of purchased intangible assets	0	119
Asset sale related costs	12	329
Restructuring charges	0	179
Total operating expenses	22,344	27,666
Income (loss) from operations	7,382	(11,929)
Interest income	98	99
Interest expense	(378)	(493)
Other income (expense), net	1,198	(1,598)
Total interest and other income (expense), net	918	(1,992)
Income (loss) before income taxes	8,300	(13,921)
Income tax provision	(1,993)	(170)
Net income (loss)	$ 6,307	$ (14,091)
Basic net income (loss) per share (in dollars per share)	$ 0.13	$ (0.30)
Diluted net income (loss) per share (in dollars per share)	$ 0.12	$ (0.30)
Weighted average shares used to compute basic net income (loss) per share (in shares)	48,615	46,414
Weighted average shares used to compute diluted net income (loss) per share (in shares)	50,617	46,414

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 6,307	$ (14,091)
Other comprehensive income (loss):
Foreign currency translation adjustments, net of zero tax	(1,970)	2,937
Total other comprehensive (loss) income	(1,970)	2,937
Comprehensive income (loss)	$ 4,337	$ (11,154)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustments, tax	$ 0	$ 0

Condenced Consolidated Statemen

Condenced Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive loss	Accumulated deficit
Beginning balance (in shares) at Dec. 31, 2018		46,378
Beginning balance at Dec. 31, 2018	$ 160,240	$ 116	$ 564,722	$ (7,126)	$ (397,472)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	(11,154)			2,937	(14,091)
Issuance of common stock upon exercise of stock options (in shares)		48
Issuance of common stock upon exercise of stock options	166	$ 0	166
Issuance of common stock under employee stock purchase plan (in shares)		0
Issuance of common stock under employee stock purchase plan	0	$ 0	0
Issuance of common stock for vested restricted stock units (in shares)		42
Issuance of common stock for vested restricted stock units	0	$ 0	0
Tax withholding related to vesting of restricted stock units (in shares)		(13)
Tax withholding related to vesting of restricted stock units	(82)		(82)
Stock-based compensation costs	3,388		3,388
Ending Balance (in shares) at Mar. 31, 2019		46,455
Ending balance at Mar. 31, 2019	152,558	$ 116	568,194	(4,189)	(411,563)
Beginning balance (in shares) at Dec. 31, 2019		48,526
Beginning balance at Dec. 31, 2019	160,206	$ 121	582,504	(7,871)	(414,548)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	4,337			(1,970)	6,307
Issuance of common stock upon exercise of stock options (in shares)		52
Issuance of common stock upon exercise of stock options	231		231
Issuance of common stock under employee stock purchase plan (in shares)		0
Issuance of common stock under employee stock purchase plan	0	$ 0	0
Issuance of common stock for vested restricted stock units (in shares)		114
Issuance of common stock for vested restricted stock units	1	$ 1	0
Tax withholding related to vesting of restricted stock units (in shares)		(30)
Tax withholding related to vesting of restricted stock units	(219)		(219)
Stock-based compensation costs	2,682		2,682
Ending Balance (in shares) at Mar. 31, 2020		48,662
Ending balance at Mar. 31, 2020	$ 167,238	$ 122	$ 585,198	$ (9,841)	$ (408,241)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities
Net income (loss)	$ 6,307	$ (14,091)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	6,674	8,851
Stock-based compensation expense	2,518	3,338
Deferred taxes	1,214	0
Others	86	109
Loss (gain) on sale of assets and other write-offs	(25)	85
Write-down of inventories	3,011	764
Amortization of operating lease right-of-use assets	462	432
Foreign currency remeasurement	(1,118)	1,818
Change in assets and liabilities:
Accounts receivable	7,209	9,675
Inventories	(2,699)	(1,654)
Prepaid expenses and other assets	(469)	2,804
Accounts payable	523	(1,232)
Accrued and other liabilities	1,233	(2,200)
Net cash provided by operating activities	24,926	8,699
Cash flows from investing activities
Purchase of property, plant and equipment	(2,578)	(3,600)
Proceeds from sale of property, plant and equipment and other assets	109	4
Purchase of marketable securities	(24)	(43)
Net cash used in investing activities	(2,493)	(3,639)
Cash flows from financing activities
Proceeds from exercise of stock options and issuance of stock under ESPP	231	157
Tax withholding on restricted stock units	(219)	(82)
Proceeds from bank loans, net of debt issuance costs	0	5,000
Repayment of bank loans	(1,772)	(5,764)
Repayment of notes payable	0	(2,559)
Repayment of finance lease liabilities	(21)	(33)
Net cash used in financing activities	(1,781)	(3,281)
Effect of exchange rates on cash, cash equivalents and restricted cash	(254)	353
Net increase in cash, cash equivalents and restricted cash	20,398	2,132
Cash, cash equivalents and restricted cash at the beginning of the period	81,439	69,238
Cash, cash equivalents and restricted cash at the end of the period	101,837	71,370
Supplemental disclosure of non-cash investing and financing activities:
Unpaid property, plant and equipment in accounts payable	$ 1,130	$ 1,887

Basis of presentation and signi

Basis of presentation and significant accounting policies	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of presentation and significant accounting policies	Basis of presentation and significant accounting policies Basis of Presentation and Consolidation The condensed consolidated financial statements of NeoPhotonics Corporation (“NeoPhotonics” or the “Company”) as of March 31, 2020 and for the three months ended March 31, 2020 and 2019, have been prepared in accordance with the instructions on Form 10-Q pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). In accordance with those rules and regulations, the Company has omitted certain information and notes normally provided in the Company’s annual consolidated financial statements. In the opinion of management, the condensed consolidated financial statements contain all adjustments, consisting only of normal recurring items, except as otherwise noted, necessary for the fair presentation of the Company’s financial position and results of operations for the interim periods. The year-end condensed consolidated balance sheet data was derived from audited consolidated financial statements, but does not include all disclosures required by U.S. generally accepted accounting principles (“U.S. GAAP”). These condensed consolidated financial statements should be read in conjunction with the Consolidated Financial Statements and Notes thereto included in the Company’s Annual Report on Form 10-K/A for the fiscal year ended December 31, 2019. The results of operations for the three months ended March 31, 2020 are not necessarily indicative of the results expected for the entire fiscal year. All intercompany accounts and transactions have been eliminated. Certain Significant Risks and Uncertainties The Company operates in a dynamic industry and, accordingly, can be affected by a variety of factors. For example, any of the following areas could have a negative effect on the Company in terms of its future financial position, results of operations or cash flows: the general state of the U.S., China and world economies; the highly cyclical nature of the industries the Company serves; the loss of any of its larger customers; restrictions on the Company's ability to sell to foreign customers due to trade laws, regulations and requirements; disruptions of the supply chain of components needed for its products; ability to obtain additional financing; inability to meet certain debt covenants; fundamental changes in the technology underlying the Company’s products; the hiring, training and retention of key employees; successful and timely completion of product design efforts; and new product design introductions by competitors. The inputs into the Company’s judgments and estimates consider the economic implications of the Covid-19 pandemic, as the Company knows them, on its critical and significant accounting estimates. The extent to which the Covid-19 pandemic may impact its business will depend on future developments, which are highly uncertain and cannot be predicted with confidence, such as the duration of the outbreak, travel restrictions governmental mandates issued to mitigate the spread of the disease, business closures, economic disruptions, and the effectiveness of actions taken to contain and treat the virus. Accordingly, the Company expects the Covid-19 pandemic may have a negative impact on its sales and results of operations, the size and duration of which the Company is currently unable to predict. Concentration In the three months ended March 31, 2020, Huawei accounted for approximately 52% of the Company's total revenue. One other customer was greater than 10% and the Company’s top five customers represented approximately 85% of the Company’s total revenue. In the three months ended March 31, 2019, Huawei accounted for approximately 49% of the Company's total revenue. One other customer was greater than 10% and the Company’s top five customers represented approximately 87% of the Company’s total revenue. As of March 31, 2020 and December 31, 2019, one and two customers, respectively, each accounted for more than 10% of the Company’s accounts receivable. Use of Estimates The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported revenue and expenses during the reporting period. Significant estimates made by management include: the useful lives of property, plant and equipment and intangible assets as well as future cash flows to be generated by those assets; fair values of identifiable assets acquired and liabilities assumed in business combinations; allowances for doubtful accounts; valuation allowances for deferred tax assets; valuation of excess and obsolete inventories; warranty reserves; litigation accrual and recognition of stock-based compensation, among others. Actual results could differ from these estimates. Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use ("ROU") assets, other current liabilities and operating lease liabilities on the Company's condensed consolidated balance sheets. Finance leases are included in property, plant and equipment, current portion of long-term debt and long-term debt, net of current portion on the condensed consolidated balance sheets. 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 an estimate of its incremental borrowing rate based on observed market data and other information available at the lease commencement date. The operating lease ROU assets also include any lease payments made and exclude lease incentives. Lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise such options. The Company does not record leases on the condensed consolidated balance sheet with a term of one year or less. The Company does not separate lease and non-lease components but rather account for each separate component as a single lease component for all underlying classes of assets. Variable lease payments are expensed as incurred and are not included within the operating lease ROU asset and lease liability calculation. Variable lease payments primarily include reimbursements of costs incurred by lessors for common area maintenance and utilities. Lease expense for minimum operating lease payments is recognized on a straight-line basis over the lease term. Accounting Pronouncements Recently Adopted In January 2017, the FASB issued ASU 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment (“ASU 2017-04”). This standard amends the goodwill impairment test to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, up to the total amount of goodwill allocated to that reporting unit. In November 2019, the FASB issued ASU 2019-10, according to which, the new standard is effective for smaller reporting companies (“SRC”) as defined by the SEC, for fiscal years beginning after December 15, 2022 including interim periods within those fiscal years. The Company early adopted ASU 2017-04 guidance on January 1, 2020. The adoption of this standard had no material impact on the Company’s consolidated financial statements and related disclosures. In November 2018, the FASB issued ASU 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606, which clarifies that certain transactions between participants in a collaborative arrangement should be accounted for under ASC 606 when the counterparty is a customer. In addition, ASU 2018-18 precludes an entity from presenting consideration from a transaction in a collaborative arrangement as revenue from contracts with customers if the counterparty is not a customer for that transaction. This guidance is effective for the Company beginning after December 15, 2019, with early adoption permitted. The Company adopted new guidance on January 1, 2020. The adoption of ASU 2018-08 had no material impact on the Company’s consolidated financial statements and related disclosures. Recent Accounting Pronouncements Not Yet Effective In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 amends existing guidance on the impairment of financial assets and adds an impairment model that is based on expected losses rather than incurred losses and requires an entity to recognize as an allowance its estimate of expected credit losses for its financial assets. An entity will apply this guidance through a cumulative-effect adjustment to retained earnings upon adoption (a modified-retrospective approach) while a prospective transition approach is required for debt securities for which an other-than-temporary impairment had been recognized before the effective date. In November 2019, the FASB issued ASU 2019-10, according to which, the new standard is effective for smaller reporting companies (“SRC”) as defined by the SEC, for fiscal years beginning after December 15, 2022 including interim periods within those fiscal years. The Company is in the process of evaluating the impact and timing of the adoption on its consolidated financial statements and related disclosures.

Revenue

Revenue	3 Months Ended
	Mar. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Product revenue The Company develops, manufactures and sells lasers and other high speed optoelectronic products that transmit, receive, modify and switch high speed digital optical signals for communications networks. Revenue is derived primarily from the sale of hardware products. The Company sells its products worldwide, primarily to leading network equipment manufacturers. Revenue recognition Revenue is recognized upon transfer of control of promised products or services to customers in an amount that reflects the consideration the Company expects to receive in exchange for those products or services. The Company generally bears all costs, risk of loss or damage and retains title to the goods up to the point of transfer of control of promised products to customer. Revenue related to the sale of consignment inventories at customer vendor managed locations is not recognized until the products are pulled from consignment inventories by customers. In instances where acceptance of the product or solutions is specified by the customer, revenue is deferred until such required acceptance criteria have been met. Shipping and handling costs are included in the cost of goods sold. The Company presents revenue net of sales taxes and any similar assessments. Nature of products Revenue from sale of hardware products is recognized upon transfer of control to the customer. The performance obligation for the sale of hardware products is satisfied at a point in time. The Company has aligned its products in two groups - High Speed Products and Network Products and Solutions. The following presents revenue by product group (in thousands): Three Months Ended 2020 2019 High Speed Products $ 89,850 $ 70,168 Network Products and Solutions 7,551 9,198 Total revenue $ 97,401 $ 79,366 The following table presents the Company's revenue information by geographical region. Revenue is classified based on the ship to location requested by the customer. Such classification recognizes that for many customers, including those in North America or in Europe, designated shipping points are often in China or elsewhere in Asia (in thousands): Three Months Ended 2020 2019 China $ 58,909 $ 45,547 Americas 18,340 13,829 Rest of world 20,152 19,990 Total revenue $ 97,401 $ 79,366 Deferred revenue The Company records deferred revenue when cash payments are received or due in advance of the Company's performance. There were no deferred revenue balances as of March 31, 2020 and December 31, 2019. Contract assets Contract assets are rights to consideration in exchange for goods or services that the Company has transferred to a customer when such right is conditional on something other than the passage of time. Contract assets exclude any amounts presented as an accounts receivable. There were no contract assets balances as of March 31, 2020 and December 31, 2019. Refund liabilities The Company recognizes a refund liability if the Company receives consideration from a customer and expects to refund some or all of that consideration to the customer. The refund liabilities as of March 31, 2020 and December 31, 2019 were immaterial.

Net income (loss) per share

Net income (loss) per share	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income (loss) per share	Net income (loss) per share The following table sets forth the computation of the basic and diluted net income (loss) per share for the periods indicated (in thousands, except per share amounts): Three Months Ended 2020 2019 Numerator: Net income (loss) $ 6,307 $ (14,091) Denominator: Weighted average shares used to compute per share amount: Basic 48,615 46,414 Diluted 50,617 46,414 Basic net income (loss) per share $ 0.13 $ (0.30) Diluted net income (loss) per share $ 0.12 $ (0.30) The Company has excluded the impact of the following outstanding employee stock options and restricted stock units as well as the shares expected to be issued under its employee stock purchase plan from the computation of diluted net income (loss) per share, as their effect would have been antidilutive (in thousands): Three Months Ended 2020 2019 Employee stock options 975 3,145 Restricted stock units 42 2,419 Market-based restricted stock units 612 677 Employee stock purchase plan 344 414 1,973 6,655

Cash, cash equivalents, short-t

Cash, cash equivalents, short-term investments, and restricted cash	3 Months Ended
	Mar. 31, 2020
Cash and Cash Equivalents [Abstract]
Cash, cash equivalents, short-term investments, and restricted cash	Cash, cash equivalents, short-term investments and restricted cash The following table summarizes the Company’s cash, cash equivalents and restricted cash (in thousands): March 31, 2020 December 31, 2019 Cash and cash equivalents $ 90,905 $ 70,467 Restricted cash 10,932 10,972 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 101,837 $ 81,439 The following table summarizes the Company’s unrealized gains and losses related to its short-term investments in marketable securities designated as available-for-sale (in thousands): As of March 31, 2020 As of December 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Loss Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Loss Fair Value Marketable securities: Money market funds $ 7,662 $ — $ — $ 7,662 $ 7,638 $ — $ — $ 7,638 Reported as: Short-term investments $ 7,662 $ 7,638 As of March 31, 2020 and December 31, 2019, maturities of marketable securities were less than 1 year. There were no realized gains and losses on the sale of marketable securities during the three months ended March 31, 2020 and 2019. The Company did not recognize any impairment losses on its marketable securities during the three months ended March 31, 2020 or 2019. As of March 31, 2020, the Company did not have any investments in marketable securities that were in an unrealized loss position for a period in excess of 12 months.

Fair value disclosures

Fair value disclosures	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair value disclosures	Fair value disclosures Assets and Liabilities Measured at Fair Value on a Recurring Basis The following table presents the Company's assets that are measured at fair value on a recurring basis (in thousands): As of March 31, 2020 As of December 31, 2019 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Short-term investments: Money market funds $ 7,662 $ — $ — $ 7,662 $ 7,638 $ — $ — $ 7,638 Other long-term assets: Mutual funds held in Rabbi Trust $ 528 $ — $ — $ 528 $ 616 $ — $ — $ 616 The Company offers a Non-Qualified Deferred Compensation Plan (“NQDC Plan”) to a select group of its highly compensated employees. The NQDC Plan provides participants the opportunity to defer payment of certain compensation as defined in the NQDC Plan. A Rabbi Trust has been established to fund the NQDC Plan obligation, which was fully funded at March 31, 2020. The assets held by the Rabbi Trust are substantially in the form of exchange traded mutual funds and are included in the Company’s other long-term assets on its condensed consolidated balance sheets as of March 31, 2020 and December 31, 2019. There were no liabilities that are measured at fair value on a recurring basis as of March 31, 2020. Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis As of March 31, 2020 and December 31, 2019 the Company had no assets or liabilities required to be measured at fair value on a nonrecurring basis. Assets and Liabilities Not Measured at Fair Value

Asset Sale

Asset Sale	3 Months Ended
	Mar. 31, 2020
Discontinued Operations and Disposal Groups [Abstract]
Asset Sale	Asset Sale NeoRussia In December 2018, the Company entered into an agreement with Joint Stock Company Rusnano, a related party, for Joint Stock Company Rusnano group to purchase the 100% interest in the operations of NeoPhotonics Corporation, LLC, the Company's manufacturing operations in Russia. In 2018, the Company recorded additional restructuring expense of $1.6 million related to these operations, bringing the total amount accrued for the Rusnano payment derivative to $2.0 million. As of December 31, 2018, the Company had recorded assets with a carrying value of $3.0 million as held for sale. The balance for liabilities held for sale as of December 31, 2018 was immaterial. In April 2019, the Company completed the sale of 100% interest in the operations of NeoPhotonics Corporation, LLC, the Company's manufacturing operations in Russia to Joint Stock Company Rusnano, a related party. In connection with the sale, the Company received $2.0 million in cash, settled the $2.0 million exit fee and recognized a gain on asset sale of $0.9 million within operating expenses during 2019. APAT In January 2017, the Company completed the sale of its Low Speed Transceiver Products’ assets to APAT Optoelectronics Components Co., Ltd. ("APAT OE") pursuant to an asset purchase agreement dated December 14, 2016 for consideration of approximately $25.0 million (in RMB equivalent) plus approximately $1.4 million (in RMB equivalent) post-closing transaction service fees to be received under a transition services agreement with APAT OE in which the Company provided short-term manufacturing and other specific services pursuant to such agreement. The related supply chain purchase commitments and value-added tax obligations were assumed by APAT OE. The receivable and payable balances related to the transition service arrangement were $11.7 million and $11.8 million, respectively, as of March 31, 2020. As of December 31, 2016, the balance in assets held for sale was $13.9 million, consisting of $13.1 million in inventories and $0.8 million in property, plant and equipment. As a result of post-closing adjustments, total consideration was reduced by approximately $3.4 million for inventory. In addition, an immaterial amount of property, plant and equipment was reclassified from assets held for sale. Upon closing, assets sold to APAT OE were approximately $12.8 million, including approximately $12.1 million in inventories and $0.7 million in property, plant and equipment. The adjusted consideration received of approximately $21.6 million was subject to further reduction of up to $10.0 million for any indemnification claims. As of March 31, 2020, the Company has a reserve of $6.5 million within accrued and other current liabilities for warranty claims. The indemnification warranties expired on June 30, 2017. The Company recognized a $2.2 million gain on the sale of these assets within operating loss in 2017. All of the Low Speed Transceiver Products were part of the Company’s Network Products and Solutions product group and included the low speed optical network (PON) products for which the end-of-life plan was announced in mid-2016.

Balance sheet components

Balance sheet components	3 Months Ended
	Mar. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Balance sheet components	Balance sheet components Accounts receivable, net Accounts receivable, net, consists of the following (in thousands): March 31, 2020 December 31, 2019 Accounts receivable $ 61,914 $ 68,988 Trade notes receivable — 156 Allowance for doubtful accounts (251) (254) $ 61,663 $ 68,890 Inventories Inventories consist of the following (in thousands): March 31, 2020 December 31, 2019 Raw materials $ 21,987 $ 19,350 Work in process 13,957 12,262 Finished goods (1) 10,202 15,318 $ 46,146 $ 46,930 ________________________________________________________ (1) Finished goods inventory at customer vendor managed inventory locations was $1.5 million and $1.6 million as of March 31, 2020 and December 31, 2019, respectively. Prepaid expenses and other current assets Prepaid expenses and other current assets consist of the following (in thousands): March 31, 2020 December 31, 2019 Transition services agreement receivable (refer to Note 6) $ 11,680 $ 11,861 Prepaid taxes and taxes receivable 3,569 6,979 Deposits and other prepaid expenses 2,620 2,512 Other receivable 8,309 4,499 $ 26,178 $ 25,851 Purchased intangible assets Purchased intangible assets consist of the following (in thousands): March 31, 2020 December 31, 2019 Gross Accumulated Net Gross Accumulated Net Technology and patents $ 36,685 $ (35,537) $ 1,148 $ 36,880 $ (35,555) $ 1,325 Customer relationships 15,004 (15,004) — 15,089 (15,089) — Leasehold interest 1,201 (396) 805 1,222 (396) 826 $ 52,890 $ (50,937) $ 1,953 $ 53,191 $ (51,040) $ 2,151 Amortization expense relating to technology and patents and the leasehold interest intangible assets is included within cost of goods sold and customer relationships within operating expenses. The following table presents details of the amortization expense of the Company’s purchased intangible assets as reported in the condensed consolidated statements of operations (in thousands): Three Months Ended 2020 2019 Cost of goods sold $ 184 $ 184 Operating expenses — 119 Total $ 184 $ 303 The estimated future amortization expense of purchased intangible assets as of March 31, 2020, is as follows (in thousands): 2020 (remaining nine months) $ 539 2021 644 2022 27 2023 27 2024 27 Thereafter 689 $ 1,953 Accrued and other current liabilities Accrued and other current liabilities consist of the following (in thousands): March 31, 2020 December 31, 2019 Employee-related $ 19,706 $ 17,877 Transition services agreement payables (refer to Note 6) 11,759 11,765 Asset sale related warranty claims (refer to Note 6) 6,549 6,664 Operating lease liabilities, current 2,119 2,086 Income and other taxes payable 1,676 2,036 Accrued warranty 749 712 Other accrued expenses 6,152 6,341 $ 48,710 $ 47,481 Warranty accrual The table below summarizes the movement in the warranty accrual, which is included in accrued and other current liabilities (in thousands): Three Months Ended 2020 2019 Beginning balance $ 712 $ 672 Warranty accruals 225 315 Settlements (188) (248) Ending balance $ 749 $ 739 Other noncurrent liabilities Other noncurrent liabilities consist of the following (in thousands): March 31, 2020 December 31, 2019 Pension and other employee-related $ 3,958 $ 4,125 Asset retirement obligations 3,756 3,529 Deferred income tax liabilities 1,733 528 Government grant 1,172 1,380 Other 51 52 $ 10,670 $ 9,614

Debt

Debt	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Debt	Debt The table below summarizes the carrying amounts and weighted average interest rates of the Company’s debt (in thousands, except percentages): March 31, 2020 December 31, 2019 Carrying Interest Carrying Interest Long-term debt, current and noncurrent: Borrowing under Wells Fargo Credit Facility $ 26,596 2.93 % $ 27,329 3.72 % Mitsubishi Bank loans 8,803 1.05% -1.45% 9,255 1.04%-1.44% Mitsubishi Bank and Yamanashi Chuo Bank loan 5,616 1.07 % 5,868 1.07 % Total long-term debt 41,015 42,452 Finance lease liability 254 275 Unaccreted discount and issuance costs (412) (446) Total long-term debt, net of unaccreted discount and issuance costs $ 40,857 $ 42,281 Reported as: Current portion of long-term debt $ 3,066 $ 3,044 Long-term debt, net of current portion 37,791 39,237 Total long-term debt, net of unaccreted discount and issuance costs $ 40,857 $ 42,281 Notes payable and short-term borrowing The Company regularly issues notes payable to its suppliers in China. These notes are supported by non-interest bearing bank acceptance drafts issued under the Company’s existing line of credit facilities and are due three • Under the first line of credit facility with Shanghai Pudong Development Bank, the Company can borrow up to RMB 120.0 million ($16.9 million) for short-term loans at varying interest rates, or up to approximately RMB 240.0 million ($33.9 million) for bank acceptance drafts (with up to 50% compensating balance requirement). This line of credit facility expires in November 2021. In November 2017, the Company borrowed $17.0 million under this line which bore interest at 4.1%. The amount of $17.0 million under this line was repaid in May 2018. • Under the second line of credit facility with Shanghai Pudong Development Bank, which expires in November 2021, the Company can borrow up to RMB 30.0 million ($4.2 million) for short-term loans at varying interest rates, or up to approximately RMB 60.0 million ($8.5 million) for bank acceptance drafts (with up to 50% compensating balance requirement). Under these line of credit facilities, the non-interest bearing bank acceptance drafts issued in connection with the Company’s notes payable to its suppliers in China, had no outstanding balance at March 31, 2020 and December 31, 2019. As of March 31, 2020 and December 31, 2019, compensating balances relating to these bank acceptance drafts and letters of credit issued to suppliers and the Company’s subsidiaries totaled $2.5 million. Compensating balances are classified as restricted cash on the Company’s condensed consolidated balance sheets. In China, when there is a case pending in judicial court, banks may choose to limit borrowing against existing credit lines, regardless of the legitimacy of the case. The Company has a dispute pending with APAT OE in judicial court (Refer to Note 11). The Company has repaid funds borrowed and does not expect to make any additional draws against its credit facilities in China until this matter is resolved. Credit facilities In September 2017, the Company entered into a revolving line of credit agreement with Wells Fargo Bank, National Association ("Wells Fargo") as the administrative agent for a lender group (the "Wells Fargo Credit Facility" or "Credit Facility"). The Wells Fargo Credit Facility provides for borrowings equal to the lower of (a) a maximum revolver amount of $50.0 million, or (b) an amount equal to 80% - 85% of eligible accounts receivable plus 100% of qualified cash balances up to $15.0 million, less certain discretionary adjustments ("Borrowing Base"). The maximum revolver amount may be increased by up to $25.0 million, subject to certain conditions. The Credit Facility matures on June 30, 2022 and borrowings bear interest at an interest rate option of either (a) the LIBOR rate, plus an applicable margin ranging from 1.50% to 1.75% per annum, or (b) the prime lending rate, plus an applicable margin ranging from 0.50% to 0.75% per annum. The Company is also required to pay a commitment fee equal to 0.25% of the unused portion of the Credit Facility. The Credit Facility agreement ("Agreement") requires prepayment of the borrowings to the extent the outstanding balance is greater than the lesser of (a) the most recently calculated Borrowing Base, or (b) the maximum revolver amount. The Company is required to maintain a combination of certain defined cash balances and unused borrowing capacity under the Credit Facility of at least $20.0 million, of which at least $5.0 million shall include unused borrowing capacity. The Agreement also restricts the Company's ability to dispose of assets, permit change in control, merge or consolidate, make acquisitions, incur indebtedness, grant liens, make investments and make certain restricted payments. Borrowings under the Credit Facility are collateralized by substantially all of the Company's assets. On June 14, 2019, the Company entered into a First Amendment to the Credit Facility (the "Amended Credit Facility"). The Amendment removes Huawei from the list of “Eligible Accounts” as a basis for the Company’s borrowing while Huawei is on the U.S. Bureau of Industry and Security (“BIS”) “Entity List”. During the period of time while Huawei remains on the Entity List, the concentration limits of certain other customers are increased to partially offset the removal of Huawei. Additionally, until Huawei is no longer on the Entity List, the Company is required to maintain a temporary combination of certain defined unrestricted cash and unused borrowing capacity under the Credit Facility of at least $30.0 million in the U.S. and $40.0 million world-wide, of which at least $5.0 million shall include unused borrowing capacity. The Company was in compliance with the covenants of this Amended Credit Facility as of March 31, 2020 and December 31, 2019. As of March 31, 2020, the outstanding balance under the Credit Facility was $26.6 million and the weighted average rate under the LIBOR option was 2.93%. The remaining borrowing capacity as of March 31, 2020 was $7.1 million, of which $5.0 million is required to be maintained as unused borrowing capacity. The Company repaid $5.0 million in January 2019, which was borrowed in December 2018. During the three months ended March 31, 2020, $0.3 million of accrued interest was rolled into the principal amount of Wells Fargo Credit Facility. Mitsubishi Bank loans On February 25, 2015, the Company entered into certain loan agreements and related agreements with MUFG Bank, Ltd. (the “Mitsubishi Bank”) that provided for (i) a term loan in the aggregate principal amount of 500.0 million JPY ($4.4 million) (the “Term Loan A”) and (ii) a term loan in the aggregate principal amount of one billion JPY (approximately $9.2 million) (the “Term Loan B” and together with the Term Loan A, the “2015 Mitsubishi Bank Loans”). The 2015 Mitsubishi Bank Loans are secured by a mortgage on certain real property and buildings owned by the Company’s Japanese subsidiary. Interest on the 2015 Mitsubishi Bank Loans accrues and is paid monthly based upon the annual rate of the monthly Tokyo Interbank Offer Rate (TIBOR) plus 1.40%. The Term Loan A required interest only payments until the maturity date of February 23, 2018, with a lump sum payment of the aggregate principal amount on the maturity date. The Term Loan B requires equal monthly payments of principal equal to 8.3 million JPY (approximately $0.1 million) until the maturity date of February 25, 2025, with a lump sum payment of the balance of 8.4 million JPY (approximately $0.1 million) on the maturity date. Interest on the Term Loan B is accrued based upon monthly TIBOR plus 1.40% and is secured by real estate collateral. In conjunction with the execution of the Bank Loans, the Company paid a loan structuring fee, including consumption tax, of 40.5 million JPY (approximately $0.4 million). The Term Loan A of 500.0 million JPY (approximately $4.4 million) was repaid to the Mitsubishi Bank in January 2018. The 2015 Mitsubishi Bank Loans contain customary representations and warranties and customary affirmative and negative covenants applicable to the Company’s Japanese subsidiary, including, among other things, restrictions on cessation in business, management, mergers or acquisitions. The 2015 Mitsubishi Bank Loans contain financial covenants relating to minimum net assets, maximum ordinary loss and a coverage ratio covenant. The Company was in compliance with the related covenants as of March 31, 2020 and December 31, 2019. Outstanding principal balance for the Mitsubishi Term Loans was 491.7 million JPY (approximately $4.5 million) as of March 31, 2020. In March 2017, the Company entered into a loan agreement and related agreements with the Mitsubishi Bank for a term loan of 690.0 million JPY (approximately $6.4 million) (the “2017 Mitsubishi Bank Loan”) to acquire manufacturing equipment for its Japanese subsidiary. This loan is secured by the manufacturing equipment owned by the Company's subsidiary in Japan. Interest on the 2017 Mitsubishi Bank Loan is based on the annual rate of the monthly TIBOR rate plus 1.00%. The 2017 Mitsubishi Bank Loan matures on March 29, 2024 and requires monthly interest and principal payments over 72 months commencing in April 2018. The loan contains customary covenants relating to minimum net assets, maximum ordinary loss and a coverage ratio covenant. The Company was in compliance with these covenants as of March 31, 2020. The loan was available from March 31, 2017 to March 30, 2018 and 690.0 million JPY (approximately $6.4 million) under this loan was fully drawn in March 2017. Outstanding principal balance for the 2017 Mitsubishi Bank Loan was approximately 460.0 million JPY (approximately $4.3 million) as of March 31, 2020. Mitsubishi Bank and Yamanashi Chuo Bank loan In January 2018, the Company entered into a term loan agreement with Mitsubishi Bank and The Yamanashi Chuo Bank, Ltd. for a term loan in the aggregate principal amount of 850.0 million JPY (approximately $7.9 million) (the “Term Loan C”). The purpose of the Term Loan C is to obtain machinery for the core parts of the manufacturing line and payments for related expenses by the Company's subsidiary in Japan. The Term Loan C requires no additional security. The Term Loan C was available from January 29, 2018 to January 29, 2025. The full amount of the Term Loan C was drawn in January 2018. Interest on the Term Loan C is based upon the annual rate of the three months TIBOR rate plus 1.00%. The Term Loan C requires quarterly interest payments, along with the principal payments, over 82 months commencing in April 2018. The Term Loan C loan agreement contains customary representations and warranties and customary affirmative and negative covenants applicable to the Japanese Subsidiary, including, among other things, restrictions on cessation in business, management, mergers or acquisitions. The Term Loan C loan agreement contains financial covenants relating to minimum net assets and maximum ordinary loss. The Company was in compliance with these covenants as of March 31, 2020 and December 31, 2019. Outstanding principal balance for the Mitsubishi Bank and Yamanashi Chuo Bank Loan was approximately 607.1 million JPY (approximately $5.6 million) as of March 31, 2020. As of March 31, 2020, maturities of total long-term debt were as follows (in thousands): 2020 (remaining nine months) $ 2,334 2021 3,112 2022 29,708 2023 3,112 2024 2,314 Thereafter 435 $ 41,015

Leases

Leases	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Leases	Leases The Company has operating leases for offices, research and development facilities and manufacturing facilities. Leases have remaining terms of one year to seven years, some of which include options to extend the leases and some of which may include options to terminate the leases within one year. As of March 31, 2020 and December 31, 2019, an asset recorded in property, plant and equipment under a finance lease was immaterial. The components of lease expense were as follows (in thousands): Three Months Ended 2020 2019 Operating lease cost $ 759 $ 754 Variable and short-term lease cost 403 348 Total lease cost $ 1,162 $ 1,102 Other information related to leases was as follows (in thousands, except lease term and discount rate): Three Months Ended 2020 2019 Supplemental cash flow information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 718 $ 835 Right-of-use assets obtained in exchange for lease obligations: Operating leases $ — $ — Weighted average remaining lease term Operating leases 7.2 years 7.9 years Weighted average discount rate Operating leases 6.4 % 6.4 % Future minimum lease payments under non-cancelable leases as of March 31, 2020 were as follows (in thousands): Operating Leases 2020 (remaining nine months) $ 2,423 2021 3,093 2022 3,089 2023 3,039 2024 2,943 Thereafter 8,266 Total future minimum lease payments 22,853 Less imputed interest (4,736) Total $ 18,117 Operating Leases March 31, 2020 December 31, 2019 Accrued and other current liabilities $ 2,119 $ 2,086 Operating lease liabilities, noncurrent 15,998 16,543 Total $ 18,117 $ 18,629

Japan pension plan

Japan pension plan	3 Months Ended
	Mar. 31, 2020
Retirement Benefits [Abstract]
Japan pension plan	Japan pension plan The pension liability related to the Company’s Retirement Allowance Plan (“RAP”) in Japan as of March 31, 2020 was $3.7 million, of which $0.3 million was recorded in accrued and other current liabilities and the remainder in other noncurrent liabilities on the Company’s condensed consolidated balance sheet. The pension liability related to the Company’s RAP in Japan as of December 31, 2019 was $4.1 million, of which $0.6 million, was recorded in accrued and other current liabilities and the remainder in other noncurrent liabilities on the Company’s condensed consolidated balance sheet. Net periodic pension cost associated with this plan was immaterial in the three months ended March 31, 2020 and 2019.

Commitments and contingencies

Commitments and contingencies	3 Months Ended
	Mar. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	Commitments and contingencies Litigation From time to time, the Company is subject to various claims and legal proceedings, either asserted or unasserted, that arise in the ordinary course of business. The Company accrues for legal contingencies if the Company can estimate the potential liability and if the Company believes it is probable that the case will be ruled against it. If a legal claim for which the Company did not accrue is resolved against it, the Company would record the expense in the period in which the ruling was made. The Company believes that the likelihood of an ultimate amount of liability, if any, for any pending claims of any type (alone or combined) will materially affect the Company’s financial position, results of operations or cash flows is remote. The ultimate outcome of any litigation is uncertain, however, and unfavorable outcomes could have a material negative impact on the Company’s financial condition and operating results. Regardless of outcome, litigation can have an adverse impact on the Company because of defense costs, negative publicity, diversion of management resources and other factors. In January 2010, Finisar Corporation, or Finisar (acquired by II-VI, Inc. in September 2019), filed a complaint in the U.S. District Court for the Northern District of California, or the Court, against Source Photonics, Inc., MRV Communications, Inc., Oplink Communications, Inc. and the Company, or collectively, the co-defendants. In the complaint, Finisar alleged infringement of certain of its U.S. patents. In 2010 the Company filed an answer to the complaint and counterclaims, asserting two claims of patent infringement and additional claims. The Court dismissed without prejudice all co-defendants (including the Company) except Source Photonics, Inc., on grounds that such claims should have been asserted in four separate lawsuits, one against each defendant. This dismissal does not prevent Finisar from bringing a new similar lawsuit against the Company. In 2011 the Company and Finisar agreed to suspend their respective claims and in 2012 the Company and Finisar further agreed to toll their respective claims. While there has been no action on this matter since 2012, the Company is currently unable to predict the outcome of this dispute and therefore cannot determine the likelihood of loss nor estimate a range of possible loss. In December 2016, the Company was served with a lawsuit filed by Lestina International Ltd. (“Lestina”), in Santa Clara County, CA. The lawsuit is regarding a dispute of approximately $3.0 million related to purchase orders for the Company’s Low Speed Transceiver Products that was soon thereafter sold by the Company to APAT OE in January 2017. The purchase orders in question were included in the asset sale and were assumed liabilities by the purchaser of the business. The parties engaged in extensive negotiations and in January 2019, the parties agreed to a proposed settlement which was placed on the record of the Superior Court of Santa Clara County agreeing that NeoPhotonics Dongguan Co., Ltd. (“NeoDongguan”) (a wholly-owned subsidiary of the Company located in China) would pay to Lestina a total of $2.2 million. These payments were completed in two installments paid in February and June 2019. Upon Lestina's receipt of the final payment in June 2019, Lestina shipped to NeoDongguan the remaining parts from the original purchase orders. In April 2018, APAT OE filed a lawsuit in the Qianhai Court in Shenzhen, China against NeoPhotonics (China) Co., Ltd. (a wholly-owned subsidiary of the Company located in China) and NeoPhotonics Dongguan Co. Ltd. (collectively "NeoChina") and NeoPhotonics Corporation with a claim of approximately $20.0 million. The lawsuit relates to the sale of the low speed transceiver business to APAT OE from NeoChina. APAT OE claims that the business has been losing money and that APAT OE was not given all of the information about the business they purchased prior to signing the Asset Purchase Agreement. In May 2018, counsel on behalf of NeoChina filed a motion objecting to the jurisdiction, claiming that the proper jurisdiction for any dispute between these parties is the Shenzhen Court of International Arbitration (or the "Arbitration Court") and the proper parties to this dispute are NeoChina and APAT OE, pursuant to the Asset Purchase Agreement signed by APAT OE and NeoChina (or the "APA"). In June 2018 a hearing was held in the Qianhai Court in Shenzhen, China and in August 2018 the Court ruled in favor of APAT OE. In October 2018, a hearing was held in the Intermediate Court of Shenzhen (or the "Intermediate Court") on an appeal which was filed by NeoChina and in November 2018 the Intermediate Court ruled in favor of NeoChina and dismissed in totality the litigation against NeoChina, ruling that arbitration was the proper forum for such dispute resolution between the parties. The litigation continued against NeoPhotonics Corporation in Qianhai Court and Intermediate Court, where NeoPhotonics Corporation claims that there is no existing contract between APAT OE and NeoPhotonics Corporation and therefore there is no basis for litigation. In December 2019, NeoPhotonics Corporation received a notice that the case against NeoPhotonics Corporation had been dismissed in the Qianhai Court in Shenzhen, China. APAT OE has appealed this decision to the Shenzhen Intermediate Court. The Company is unable to predict the outcome of this matter and is not currently aware of the precise amount of the ongoing claim by APAT against NeoPhotonics Corporation in this lawsuit. In December 2018, APAT OE filed claims through two lawsuits against NeoChina, NeoPhotonics Corporation Limited Hong Kong (or NeoHK), Novel Centennial Limited BVI (or NeoBVI) and NeoPhotonics Corporation (collectively the "defendants") in the Intermediate Court in addition to a pre-trial preservation order. On the same day the Court issued the order to preserve approximately $29.0 million of NeoChina assets, which is the approximate amount of the revised claims by APAT OE against all defendants in the first of the two lawsuits filed in December 2018. In January 2019, there was an additional pre-trial preservation order to preserve approximately $3.8 million of NeoChina assets. The temporary pre-trial preservation order was made simultaneously to the filing of the two lawsuits, but the defendants were not served or aware of the lawsuit until later in January 2019. In the first lawsuit, the legal claims are the same as the ones APAT OE filed in April 2018 in Qianhai Court in Shenzhen, China (as described above). The difference is that instead of distributing claims in separate cases, APAT OE has combined its claims to one single case and added the additional defendants of NeoHK and NeoBVI and increased the claimed damages to approximately $29.0 million. In the second lawsuit, the claims are new and related to the alleged new issues related to a contract manufacturer located in the Philippines and claiming damages in the amount of RMB 50.9 million (approximately $7.6 million). APAT OE claims that the defendants have interfered with APAT OE’s ability to sign an engagement agreement with the contract manufacturer. The defendants believe this dispute is related to and should be under the jurisdiction that was agreed to in the APA, and therefore should be properly transferred to the Shenzhen Court of International Arbitration. On April 30, 2020, the Shenzhen Intermediate Court ruled in both lawsuits that the Court has no jurisdiction over disputes between Neo China and APAT OE and that any disputes between those parties should be transferred to the Shenzhen Court of International Arbitration. Additionally, the Court ruled that because there is no arbitration award against Neo China, the Court has no jurisdiction over NeoHK, NeoBVI, or NeoPhotonics Corporation. These rulings are subject to appeal by APAT OE and the Company is unable to predict the outcome of this matter. In February 2019, NeoChina filed a case in the Qianhai Court in Shenzhen, China against APAT OE and Zhejiang Merchants Property Insurance Company for losses and damages caused to NeoChina from APAT OE’s previously granted property preservation. The claim was for approximately RMB 350,000 (approximately $52,000) in damages and legal fees and was heard in May 2019. In December 2019 NeoChina received a final judgment in favor of the defendants. APAT Arbitration In June 2017, APAT OE filed an arbitration claim in the Shenzhen Court of International Arbitration (or the Arbitration Court) against NeoChina (collectively both of the Company’s China subsidiaries), claiming that approximately $1.5 million of the inventory that was sold to APAT OE by NeoChina in an Asset Purchase Agreement executed between the parties on December 14, 2016 was aged inventory and of no value. The arbitration was heard in the Arbitration Court in August 2017. In October 2017, NeoChina was informed that it was successful in the defense of the dispute and was also successful in its counterclaim against APAT OE. NeoChina was awarded approximately RMB 700,000 (approximately $110,000) in compensatory damages and attorney fees as well as having the approximately $1.5 million claim against it rejected in its entirety. In April 2018, APAT OE filed a Notice of Judicial Review of the arbitration judgment in the Shenzhen Intermediate Court in Shenzhen, China. The case was heard in May 2018, and NeoChina was successful in disputing the Judicial Review, which means that the arbitration judgment against APAT OE and in favor of NeoChina stands. In July 2018, NeoChina applied together to the Shenzhen Intermediate Court for enforcement of the previous arbitration ruling because APAT OE had refused to perform the arbitral award. In October 2018, the Court enforced the award, officially closing this arbitration matter. In July 2018, NeoChina filed an arbitration claim against APAT OE in the Arbitration Court claiming approximately $12.0 million in damages as related to liability under the APA. NeoChina also was granted a property preservation of APAT OE’s bank accounts. In February 2019 NeoChina applied to the Arbitration Court to reduce the claim to $7.1 million according to the evidence of confirmation requests received by NeoChina. In August 2019, NeoChina applied to the Arbitration Court to modify the claim to $8.1 million subject to the supplementary evidence of NeoChina. On March 31, 2020, the Arbitration Court ruled in favor of NeoChina and awarded NeoChina 54,607,000 RMB (approximately $7.7 million). On April 27, 2020, NeoChina filed an enforcement action in the Intermediate People's Court of Shenzhen Municipality to enforce this arbitration award. In November 2018, APAT OE filed an additional arbitration claim against NeoChina claiming approximately $7.8 million for liability under the APA. In March 2019, NeoChina filed a response and counterclaim against APAT OE including a claim for attorney fees in the amount of RMB 810,000 (approximately $121,000). This matter was heard in the same hearing as the NeoChina arbitration claim referenced above. On March 31, 2020, the Arbitration Court ruled in NeoChina's' favor and awarded 846,000 RMB (approximately $119,000) for attorney's fees and arbitration fees. On April 27, 2020, NeoChina filed an enforcement action in the Intermediate People's Court of Shenzhen Municipality to enforce this arbitration award. Indemnifications In the normal course of business, the Company enters into agreements that contain a variety of representations and warranties and provides for general indemnification. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future, but have not yet been made. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. However, the Company may record charges in the future as a result of these indemnification obligations.

Stockholders' equity

Stockholders' equity	3 Months Ended
	Mar. 31, 2020
Stockholders' Equity Note [Abstract]
Stockholders’ equity	Stockholders’ equity Common Stock As of March 31, 2020, the Company had reserved 9,273,221 common stock for issuance under its equity incentive plans and 1,717,211 common stock shares for issuance under its employee stock purchase plan. Accumulated Other Comprehensive Loss The components of accumulated other comprehensive loss, net of related taxes, were as follows (in thousands): Foreign Currency Translation Adjustments Defined Benefit Pension Plan Adjustment Total Accumulated Other Comprehensive Loss Balance as of December 31, 2019 $ 7,641 $ 230 $ 7,871 Other comprehensive loss, net of taxes of zero 1,970 — 1,970 Balance as of March 31, 2020 $ 9,611 $ 230 $ 9,841 No material amounts were reclassified out of accumulated other comprehensive income during the three months ended March 31, 2020 and 2019 for realized gains or losses on available-for-sale securities. Accumulated Deficit Approximately $9.2 million of the Company’s retained earnings within its total accumulated deficit as of December 31, 2019 was subject to restriction due to the fact that the Company’s subsidiaries in China are required to set aside at least 10% of their respective accumulated profits each year end to fund statutory common reserves.

Restricted net assets

Restricted net assets	3 Months Ended
	Mar. 31, 2020
Restricted Net Assets [Abstract]
Restricted net assets	Restricted net assets The Company’s consolidated subsidiaries operating in China and Japan are restricted from transferring funds or assets to its parent company in the form of cash dividends, loans or advances. As of March 31, 2020 and December 31, 2019, the Company's consolidated subsidiaries had $20.9 million and $21.1 million, respectively, of restricted net assets. This compares to the Company's consolidated net assets of $167.2 million and $160.2 million as of March 31, 2020 and December 31, 2019, respectively, which consisted of (in thousands): March 31, 2020 December 31, 2019 Cash restricted in China as a result of ongoing litigation and unfulfilled government grants $ 10,896 $ 10,936 China earnings restricted to fund statutory common reserves in China 9,081 9,240 Loan agreements in Japan requiring local subsidiaries to maintain minimum net asset levels 925 920 Total restricted net assets in the Company's consolidated subsidiaries $ 20,902 $ 21,096

Stock-based compensation

Stock-based compensation	3 Months Ended
	Mar. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock-based compensation	Stock-based compensation The following table summarizes the stock-based compensation expense recognized in the three months ended March 31, 2020 and 2019 (in thousands): Three Months Ended 2020 2019 Cost of goods sold $ 537 $ 601 Research and development 758 881 Sales and marketing 530 678 General and administrative 693 1,178 $ 2,518 $ 3,338 Determining Fair Value The Company estimated the fair value of certain stock-based awards using a Black-Scholes-Merton valuation model. Stock Options and Restricted Stock Units (RSUs) The following table summarizes the Company’s stock option and RSU activity, excluding market-based RSUs, during the three months ended March 31, 2020: Stock Options Restricted Stock Units Number of Weighted Number of Weighted Balance as of December 31, 2019 2,598,745 $ 5.93 3,170,981 $ 5.80 Granted — — 224,131 6.72 Exercised/Converted (52,501) 4.40 (114,188) 5.96 Cancelled/Forfeited (23,505) 11.15 (61,675) 6.10 Balance as of March 31, 2020 2,522,739 5.91 3,219,249 5.85 At March 31, 2020, the Company had $0.5 million of unrecognized stock-based compensation expense for stock options, net of estimated forfeitures. At March 31, 2020, the Company had $11.7 million of unrecognized stock-based compensation expense for RSUs, excluding market-based RSUs, net of estimated forfeitures. Market-based Restricted Stock Units As of March 31, 2020, the Company has granted 705,000 shares of market-based RSUs to certain employees. These RSUs will vest if the 30-day weighted average closing price of the Company's common stock is equal to or greater than certain price targets per share and the recipients remain in continuous service with the Company through such service period. No market-based RSUs have vested and 93,500 market-based RSUs have been cancelled through March 31, 2020. The weighted average grant-date fair value per share of market-based RSUs granted during 2019 and 2018 was approximately $4.86 and $5.82 per share, respectively. As of March 31, 2020, the Company had $1.1 million of unrecognized stock-based compensation expense for these RSUs, net of estimated forfeitures, which will be recognized over the remaining weighted-average period of 1.30 years. The fair value of market-based RSUs was measured on the grant date using Monte Carlo simulation model with the following assumptions: Market-based restricted stock units Assumptions Weighted-average volatility 66% Risk-free interest rate 2.79% Expected dividends —% Stock Appreciation Units (SAU) SAUs are liability classified share-based awards. Outstanding SAUs are re-measured each reporting period at fair value until settlement. The Company did not grant any SAUs during the three months ended March 31, 2020 or 2019. As of March 31, 2020 and December 31, 2019, there were 153,404 and 163,471 SAUs outstanding, respectively, and related SAU liabilities were $0.5 million and $0.8 million, respectively. Employee Stock Purchase Plan (ESPP)

Income taxes

Income taxes	3 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income taxes	Income taxes The provision for income taxes in the periods presented is based upon the income (loss) before income taxes (in thousands): Three Months Ended 2020 2019 Income tax provision $ (1,993) $ (170) The Company’s income tax provision in the three months ended March 31, 2020 was due to income taxes on earnings from operations in the U.S. and foreign tax jurisdictions. The Company’s income tax provision in the three months ended March 31, 2019 was primarily related to income taxes of the Company’s non-U.S. operations. The increase in income tax expense for the three months ended March 31, 2020, as compared to the same period in 2019 was primarily due to increased earnings from its U.S. operations for the three months ended March 31, 2020 while the Company has historically experienced net losses in the U.S. The Company conducts its business globally and its operating income is subject to varying rates of tax in the U.S., China and Japan. Consequently, the Company’s effective tax rate is dependent upon the geographic distribution of its earnings or losses and the tax laws and regulations in each geographical region. Due to historical losses in the U.S., the Company has a full valuation allowance on its U.S. federal and state deferred tax assets. Management continues to evaluate the realizability of deferred tax assets and the related valuation allowance. If management's assessment of the deferred tax assets or the corresponding valuation allowance were to change, the Company would record the related adjustment to income during the period in which management makes the determination. As of March 31, 2020, there were no material changes to either the nature or the amounts of the uncertain tax positions previously determined for the year ended December 31, 2019. On March 27, 2020, the “Coronavirus Aid, Relief, and Economic Security Act” (“CARES Act”) was signed into law. The new legislation includes a number of income tax provisions applicable to individuals and businesses. Due to historical net operating losses incurred in the U.S., the CARES Act did not have material impacts on the Company’s condensed consolidated financial statements as of March 31, 2020. The Company continues to examine the elements of the CARES Act and the impacts they may have on its future business.

Subsequent events

Subsequent events	3 Months Ended
	Mar. 31, 2020
Subsequent Events [Abstract]
Subsequent events	Subsequent events On April 13, 2020, the Company’s 2010 Equity Incentive Plan (the “2010 Plan”) terminated in accordance with its terms. On April 14, 2020, the Company’s Board of Directors approved a 2020 Equity Incentive Plan (the “2020 Plan”), to establish a new equity plan and share reserve for the grant of stock options, restricted stock unit awards and other awards. The 2020 Plan is subject to its approval by the Company’s stockholders and is included as a proposal at the Company’s annual meeting of stockholders scheduled for June 2, 2020. In connection with the approval of the 2020 Plan, the Board of Directors also terminated the Company’s 2011 Inducement Award Plan (the “Inducement Plan”). If the 2020 Plan is approved by the Company’s stockholders, the aggregate number of shares of its common stock that may be issued under the 2020 Plan will not exceed the sum of (i) 2,121,414 shares and (ii) certain shares subject to outstanding awards granted under the 2010 Plan or the Inducement Plan that may become available for issuance under the 2020 Plan, as such shares become available from time to time. No additional awards may be granted under the 2010 Plan or the Inducement Plan.

Basis of presentation and sig_2

Basis of presentation and significant accounting policies (Policies)	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The condensed consolidated financial statements of NeoPhotonics Corporation (“NeoPhotonics” or the “Company”) as of March 31, 2020 and for the three months ended March 31, 2020 and 2019, have been prepared in accordance with the instructions on Form 10-Q pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). In accordance with those rules and regulations, the Company has omitted certain information and notes normally provided in the Company’s annual consolidated financial statements. In the opinion of management, the condensed consolidated financial statements contain all adjustments, consisting only of normal recurring items, except as otherwise noted, necessary for the fair presentation of the Company’s financial position and results of operations for the interim periods. The year-end condensed consolidated balance sheet data was derived from audited consolidated financial statements, but does not include all disclosures required by U.S. generally accepted accounting principles (“U.S. GAAP”). These condensed consolidated financial statements should be read in conjunction with the Consolidated Financial Statements and Notes thereto included in the Company’s Annual Report on Form 10-K/A for the fiscal year ended December 31, 2019. The results of operations for the three months ended March 31, 2020 are not necessarily indicative of the results expected for the entire fiscal year. All intercompany accounts and transactions have been eliminated.
Certain Significant Risks And Uncertainties	Certain Significant Risks and Uncertainties The Company operates in a dynamic industry and, accordingly, can be affected by a variety of factors. For example, any of the following areas could have a negative effect on the Company in terms of its future financial position, results of operations or cash flows: the general state of the U.S., China and world economies; the highly cyclical nature of the industries the Company serves; the loss of any of its larger customers; restrictions on the Company's ability to sell to foreign customers due to trade laws, regulations and requirements; disruptions of the supply chain of components needed for its products; ability to obtain additional financing; inability to meet certain debt covenants; fundamental changes in the technology underlying the Company’s products; the hiring, training and retention of key employees; successful and timely completion of product design efforts; and new product design introductions by competitors. The inputs into the Company’s judgments and estimates consider the economic implications of the Covid-19 pandemic, as the Company knows them, on its critical and significant accounting estimates. The extent to which the Covid-19 pandemic may impact its business will depend on future developments, which are highly uncertain and cannot be predicted with confidence, such as the duration of the outbreak, travel restrictions governmental mandates issued to mitigate the spread of the disease, business closures, economic disruptions, and the effectiveness of actions taken to contain and treat the virus. Accordingly, the Company expects the Covid-19 pandemic may have a negative impact on its sales and results of operations, the size and duration of which the Company is currently unable to predict.
Concentration	In the three months ended March 31, 2020, Huawei accounted for approximately 52% of the Company's total revenue. One other customer was greater than 10% and the Company’s top five customers represented approximately 85% of the Company’s total revenue. In the three months ended March 31, 2019, Huawei accounted for approximately 49% of the Company's total revenue. One other customer was greater than 10% and the Company’s top five customers represented approximately 87% of the Company’s total revenue.
Use of Estimates	Use of Estimates The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported revenue and expenses during the reporting period. Significant estimates made by management include: the useful lives of property, plant and equipment and intangible assets as well as future cash flows to be generated by those assets; fair values of identifiable assets acquired and liabilities assumed in business combinations; allowances for doubtful accounts; valuation allowances for deferred tax assets; valuation of excess and obsolete inventories; warranty reserves; litigation accrual and recognition of stock-based compensation, among others. Actual results could differ from these estimates.
Leases	Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use ("ROU") assets, other current liabilities and operating lease liabilities on the Company's condensed consolidated balance sheets. Finance leases are included in property, plant and equipment, current portion of long-term debt and long-term debt, net of current portion on the condensed consolidated balance sheets. 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 an estimate of its incremental borrowing rate based on observed market data and other information available at the lease commencement date. The operating lease ROU assets also include any lease payments made and exclude lease incentives. Lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise such options. The Company does not record leases on the condensed consolidated balance sheet with a term of one year or less. The Company does not separate lease and non-lease components but rather account for each separate component as a single lease component for all underlying classes of assets. Variable lease payments are expensed as incurred and are not included within the operating lease ROU asset and lease liability calculation. Variable lease payments primarily include reimbursements of costs incurred by lessors for common area maintenance and utilities. Lease expense for minimum operating lease payments is recognized on a straight-line basis over the lease term.
Accounting Pronouncements Recently Adopted/Recent Accounting Pronouncements Not Yet Effective	Accounting Pronouncements Recently Adopted In January 2017, the FASB issued ASU 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment (“ASU 2017-04”). This standard amends the goodwill impairment test to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, up to the total amount of goodwill allocated to that reporting unit. In November 2019, the FASB issued ASU 2019-10, according to which, the new standard is effective for smaller reporting companies (“SRC”) as defined by the SEC, for fiscal years beginning after December 15, 2022 including interim periods within those fiscal years. The Company early adopted ASU 2017-04 guidance on January 1, 2020. The adoption of this standard had no material impact on the Company’s consolidated financial statements and related disclosures. In November 2018, the FASB issued ASU 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606, which clarifies that certain transactions between participants in a collaborative arrangement should be accounted for under ASC 606 when the counterparty is a customer. In addition, ASU 2018-18 precludes an entity from presenting consideration from a transaction in a collaborative arrangement as revenue from contracts with customers if the counterparty is not a customer for that transaction. This guidance is effective for the Company beginning after December 15, 2019, with early adoption permitted. The Company adopted new guidance on January 1, 2020. The adoption of ASU 2018-08 had no material impact on the Company’s consolidated financial statements and related disclosures. Recent Accounting Pronouncements Not Yet Effective In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 amends existing guidance on the impairment of financial assets and adds an impairment model that is based on expected losses rather than incurred losses and requires an entity to recognize as an allowance its estimate of expected credit losses for its financial assets. An entity will apply this guidance through a cumulative-effect adjustment to retained earnings upon adoption (a modified-retrospective approach) while a prospective transition approach is required for debt securities for which an other-than-temporary impairment had been recognized before the effective date. In November 2019, the FASB issued ASU 2019-10, according to which, the new standard is effective for smaller reporting companies (“SRC”) as defined by the SEC, for fiscal years beginning after December 15, 2022 including interim periods within those fiscal years. The Company is in the process of evaluating the impact and timing of the adoption on its consolidated financial statements and related disclosures.

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2020
Revenue from Contract with Customer [Abstract]
Schedule of revenue by product group and geographical region	The following presents revenue by product group (in thousands): Three Months Ended 2020 2019 High Speed Products $ 89,850 $ 70,168 Network Products and Solutions 7,551 9,198 Total revenue $ 97,401 $ 79,366 The following table presents the Company's revenue information by geographical region. Revenue is classified based on the ship to location requested by the customer. Such classification recognizes that for many customers, including those in North America or in Europe, designated shipping points are often in China or elsewhere in Asia (in thousands): Three Months Ended 2020 2019 China $ 58,909 $ 45,547 Americas 18,340 13,829 Rest of world 20,152 19,990 Total revenue $ 97,401 $ 79,366

Net income (loss) per share (Ta

Net income (loss) per share (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Schedule of computation of basic and diluted net income per share	The following table sets forth the computation of the basic and diluted net income (loss) per share for the periods indicated (in thousands, except per share amounts): Three Months Ended 2020 2019 Numerator: Net income (loss) $ 6,307 $ (14,091) Denominator: Weighted average shares used to compute per share amount: Basic 48,615 46,414 Diluted 50,617 46,414 Basic net income (loss) per share $ 0.13 $ (0.30) Diluted net income (loss) per share $ 0.12 $ (0.30)
Schedule of potentially dilutive securities excluded from computation of diluted net income per share attributable to common stockholders	The Company has excluded the impact of the following outstanding employee stock options and restricted stock units as well as the shares expected to be issued under its employee stock purchase plan from the computation of diluted net income (loss) per share, as their effect would have been antidilutive (in thousands): Three Months Ended 2020 2019 Employee stock options 975 3,145 Restricted stock units 42 2,419 Market-based restricted stock units 612 677 Employee stock purchase plan 344 414 1,973 6,655

Cash, cash equivalents, short_2

Cash, cash equivalents, short-term investments, and restricted cash (Tables)	3 Months Ended
	Mar. 31, 2020
Cash and Cash Equivalents [Abstract]
Schedule of cash, cash equivalents, short-term investments and restricted cash	The following table summarizes the Company’s cash, cash equivalents and restricted cash (in thousands): March 31, 2020 December 31, 2019 Cash and cash equivalents $ 90,905 $ 70,467 Restricted cash 10,932 10,972 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 101,837 $ 81,439
Schedule of unrealized gains and losses related to cash equivalents and short-term investments in marketable securities	The following table summarizes the Company’s unrealized gains and losses related to its short-term investments in marketable securities designated as available-for-sale (in thousands): As of March 31, 2020 As of December 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Loss Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Loss Fair Value Marketable securities: Money market funds $ 7,662 $ — $ — $ 7,662 $ 7,638 $ — $ — $ 7,638 Reported as: Short-term investments $ 7,662 $ 7,638

Fair value disclosures (Tables)

Fair value disclosures (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of fair value of financial assets	The following table presents the Company's assets that are measured at fair value on a recurring basis (in thousands): As of March 31, 2020 As of December 31, 2019 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Short-term investments: Money market funds $ 7,662 $ — $ — $ 7,662 $ 7,638 $ — $ — $ 7,638 Other long-term assets: Mutual funds held in Rabbi Trust $ 528 $ — $ — $ 528 $ 616 $ — $ — $ 616

Balance sheet components (Table

Balance sheet components (Tables)	3 Months Ended
	Mar. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Schedule of accounts receivable, net	Accounts receivable, net, consists of the following (in thousands): March 31, 2020 December 31, 2019 Accounts receivable $ 61,914 $ 68,988 Trade notes receivable — 156 Allowance for doubtful accounts (251) (254) $ 61,663 $ 68,890
Schedule of inventories, net	Inventories consist of the following (in thousands): March 31, 2020 December 31, 2019 Raw materials $ 21,987 $ 19,350 Work in process 13,957 12,262 Finished goods (1) 10,202 15,318 $ 46,146 $ 46,930 ________________________________________________________ (1) Finished goods inventory at customer vendor managed inventory locations was $1.5 million and $1.6 million as of March 31, 2020 and December 31, 2019, respectively.
Schedule of prepaid expenses and other current assets	Prepaid expenses and other current assets consist of the following (in thousands): March 31, 2020 December 31, 2019 Transition services agreement receivable (refer to Note 6) $ 11,680 $ 11,861 Prepaid taxes and taxes receivable 3,569 6,979 Deposits and other prepaid expenses 2,620 2,512 Other receivable 8,309 4,499 $ 26,178 $ 25,851
Schedule of purchased intangible assets	Purchased intangible assets consist of the following (in thousands): March 31, 2020 December 31, 2019 Gross Accumulated Net Gross Accumulated Net Technology and patents $ 36,685 $ (35,537) $ 1,148 $ 36,880 $ (35,555) $ 1,325 Customer relationships 15,004 (15,004) — 15,089 (15,089) — Leasehold interest 1,201 (396) 805 1,222 (396) 826 $ 52,890 $ (50,937) $ 1,953 $ 53,191 $ (51,040) $ 2,151
Schedule of amortization expense of purchased intangible assets	The following table presents details of the amortization expense of the Company’s purchased intangible assets as reported in the condensed consolidated statements of operations (in thousands): Three Months Ended 2020 2019 Cost of goods sold $ 184 $ 184 Operating expenses — 119 Total $ 184 $ 303
Schedule of estimated future amortization expense of purchased intangible assets	The estimated future amortization expense of purchased intangible assets as of March 31, 2020, is as follows (in thousands): 2020 (remaining nine months) $ 539 2021 644 2022 27 2023 27 2024 27 Thereafter 689 $ 1,953
Schedule of accrued and other current liabilities	Accrued and other current liabilities consist of the following (in thousands): March 31, 2020 December 31, 2019 Employee-related $ 19,706 $ 17,877 Transition services agreement payables (refer to Note 6) 11,759 11,765 Asset sale related warranty claims (refer to Note 6) 6,549 6,664 Operating lease liabilities, current 2,119 2,086 Income and other taxes payable 1,676 2,036 Accrued warranty 749 712 Other accrued expenses 6,152 6,341 $ 48,710 $ 47,481
Schedule of warranty accrual	The table below summarizes the movement in the warranty accrual, which is included in accrued and other current liabilities (in thousands): Three Months Ended 2020 2019 Beginning balance $ 712 $ 672 Warranty accruals 225 315 Settlements (188) (248) Ending balance $ 749 $ 739
Schedule of other noncurrent liabilities	Other noncurrent liabilities consist of the following (in thousands): March 31, 2020 December 31, 2019 Pension and other employee-related $ 3,958 $ 4,125 Asset retirement obligations 3,756 3,529 Deferred income tax liabilities 1,733 528 Government grant 1,172 1,380 Other 51 52 $ 10,670 $ 9,614

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Schedule of carrying amount and weighted average interest rate of the company's debt	The table below summarizes the carrying amounts and weighted average interest rates of the Company’s debt (in thousands, except percentages): March 31, 2020 December 31, 2019 Carrying Interest Carrying Interest Long-term debt, current and noncurrent: Borrowing under Wells Fargo Credit Facility $ 26,596 2.93 % $ 27,329 3.72 % Mitsubishi Bank loans 8,803 1.05% -1.45% 9,255 1.04%-1.44% Mitsubishi Bank and Yamanashi Chuo Bank loan 5,616 1.07 % 5,868 1.07 % Total long-term debt 41,015 42,452 Finance lease liability 254 275 Unaccreted discount and issuance costs (412) (446) Total long-term debt, net of unaccreted discount and issuance costs $ 40,857 $ 42,281 Reported as: Current portion of long-term debt $ 3,066 $ 3,044 Long-term debt, net of current portion 37,791 39,237 Total long-term debt, net of unaccreted discount and issuance costs $ 40,857 $ 42,281
Schedule of maturities of long-term debt	As of March 31, 2020, maturities of total long-term debt were as follows (in thousands): 2020 (remaining nine months) $ 2,334 2021 3,112 2022 29,708 2023 3,112 2024 2,314 Thereafter 435 $ 41,015

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Schedule of lease, cost	The components of lease expense were as follows (in thousands): Three Months Ended 2020 2019 Operating lease cost $ 759 $ 754 Variable and short-term lease cost 403 348 Total lease cost $ 1,162 $ 1,102 Other information related to leases was as follows (in thousands, except lease term and discount rate): Three Months Ended 2020 2019 Supplemental cash flow information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 718 $ 835 Right-of-use assets obtained in exchange for lease obligations: Operating leases $ — $ — Weighted average remaining lease term Operating leases 7.2 years 7.9 years Weighted average discount rate Operating leases 6.4 % 6.4 %
Schedule of future minimum lease payments under non-cancellable leases	Future minimum lease payments under non-cancelable leases as of March 31, 2020 were as follows (in thousands): Operating Leases 2020 (remaining nine months) $ 2,423 2021 3,093 2022 3,089 2023 3,039 2024 2,943 Thereafter 8,266 Total future minimum lease payments 22,853 Less imputed interest (4,736) Total $ 18,117
Schedule of operating leases	Operating Leases March 31, 2020 December 31, 2019 Accrued and other current liabilities $ 2,119 $ 2,086 Operating lease liabilities, noncurrent 15,998 16,543 Total $ 18,117 $ 18,629

Stockholders' equity (Tables)

Stockholders' equity (Tables)	3 Months Ended
	Mar. 31, 2020
Stockholders' Equity Note [Abstract]
Schedule of accumulated other comprehensive income, net of related taxes	The components of accumulated other comprehensive loss, net of related taxes, were as follows (in thousands): Foreign Currency Translation Adjustments Defined Benefit Pension Plan Adjustment Total Accumulated Other Comprehensive Loss Balance as of December 31, 2019 $ 7,641 $ 230 $ 7,871 Other comprehensive loss, net of taxes of zero 1,970 — 1,970 Balance as of March 31, 2020 $ 9,611 $ 230 $ 9,841

Restricted net assets (Tables)

Restricted net assets (Tables)	3 Months Ended
	Mar. 31, 2020
Restricted Net Assets [Abstract]
Schdule of restrictions on net assets	As of March 31, 2020 and December 31, 2019, the Company's consolidated subsidiaries had $20.9 million and $21.1 million, respectively, of restricted net assets. This compares to the Company's consolidated net assets of $167.2 million and $160.2 million as of March 31, 2020 and December 31, 2019, respectively, which consisted of (in thousands): March 31, 2020 December 31, 2019 Cash restricted in China as a result of ongoing litigation and unfulfilled government grants $ 10,896 $ 10,936 China earnings restricted to fund statutory common reserves in China 9,081 9,240 Loan agreements in Japan requiring local subsidiaries to maintain minimum net asset levels 925 920 Total restricted net assets in the Company's consolidated subsidiaries $ 20,902 $ 21,096

Stock-based compensation (Table

Stock-based compensation (Tables)	3 Months Ended
	Mar. 31, 2020
Share-based Payment Arrangement [Abstract]
Schedule of stock based compensation expense	The following table summarizes the stock-based compensation expense recognized in the three months ended March 31, 2020 and 2019 (in thousands): Three Months Ended 2020 2019 Cost of goods sold $ 537 $ 601 Research and development 758 881 Sales and marketing 530 678 General and administrative 693 1,178 $ 2,518 $ 3,338
Schedule of stock option and restricted stock unit activity	The following table summarizes the Company’s stock option and RSU activity, excluding market-based RSUs, during the three months ended March 31, 2020: Stock Options Restricted Stock Units Number of Weighted Number of Weighted Balance as of December 31, 2019 2,598,745 $ 5.93 3,170,981 $ 5.80 Granted — — 224,131 6.72 Exercised/Converted (52,501) 4.40 (114,188) 5.96 Cancelled/Forfeited (23,505) 11.15 (61,675) 6.10 Balance as of March 31, 2020 2,522,739 5.91 3,219,249 5.85
Schedule of estimated fair value of certain stock-based awards using Black-Scholes-Merton valuation model	The fair value of market-based RSUs was measured on the grant date using Monte Carlo simulation model with the following assumptions: Market-based restricted stock units Assumptions Weighted-average volatility 66% Risk-free interest rate 2.79% Expected dividends —%

Income taxes (Tables)

Income taxes (Tables)	3 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of income tax (provisions) benefits	The provision for income taxes in the periods presented is based upon the income (loss) before income taxes (in thousands): Three Months Ended 2020 2019 Income tax provision $ (1,993) $ (170)

Basis of presentation and sig_3

Basis of presentation and significant accounting policies (Details) - Revenue	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Huawei Technologies
Concentration Risk [Line Items]
Percentage of concentration of credit risk	52.00%	49.00%
Other Customer
Concentration Risk [Line Items]
Percentage of concentration of credit risk	10.00%	10.00%
Top Five Customers
Concentration Risk [Line Items]
Percentage of concentration of credit risk	85.00%	87.00%

Revenue - Revenue by Product Gr

Revenue - Revenue by Product Group (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 97,401	$ 79,366
High Speed Products
Disaggregation of Revenue [Line Items]
Total revenue	89,850	70,168
Network Products and Solutions
Disaggregation of Revenue [Line Items]
Total revenue	$ 7,551	$ 9,198

Revenue - Revenue from External

Revenue - Revenue from External Customers by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 97,401	$ 79,366
China
Disaggregation of Revenue [Line Items]
Total revenue	58,909	45,547
Americas
Disaggregation of Revenue [Line Items]
Total revenue	18,340	13,829
Rest of world
Disaggregation of Revenue [Line Items]
Total revenue	$ 20,152	$ 19,990

Net income (loss) per share - C

Net income (loss) per share - Computation of Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Numerator:
Net income (loss)	$ 6,307	$ (14,091)
Weighted average shares used to compute per share amount:
Basic (in shares)	48,615	46,414
Diluted (in shares)	50,617	46,414
Basic net income (loss) per share (in dollars per share)	$ 0.13	$ (0.30)
Diluted net income (loss) per share (in dollars per share)	$ 0.12	$ (0.30)

Net income (loss) per share - P

Net income (loss) per share - Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss per Share Attributable to Common Stockholders (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Potentially dilutive securities, excluded from computation of diluted net income (loss) per share (in shares)	1,973	6,655
Employee stock options
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Potentially dilutive securities, excluded from computation of diluted net income (loss) per share (in shares)	975	3,145
Restricted stock units
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Potentially dilutive securities, excluded from computation of diluted net income (loss) per share (in shares)	42	2,419
Market-based restricted stock units
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Potentially dilutive securities, excluded from computation of diluted net income (loss) per share (in shares)	612	677
Employee stock purchase plan
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Potentially dilutive securities, excluded from computation of diluted net income (loss) per share (in shares)	344	414

Cash, cash equivalents, short_3

Cash, cash equivalents, short-term investments and restricted cash - Short-term Investments and Restricted Cash and Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 90,905	$ 70,467
Restricted cash	10,932	10,972
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 101,837	$ 81,439	$ 71,370	$ 69,238

Cash, cash equivalents, short_4

Cash, cash equivalents, short-term investments and restricted cash - Summary of Unrealized Gains and Losses (Details)	3 Months Ended
	Mar. 31, 2020USD ($)investment	Mar. 31, 2019USD ($)	Dec. 31, 2019USD ($)
Debt Securities, Available-for-sale [Line Items]
Impairment losses on marketable securities	$ 0	$ 0
Number of marketable securities in an unrealized loss position | investment	0
Money market funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 7,662,000		$ 7,638,000
Gross Unrealized Gains	0		0
Gross Unrealized Loss	0		0
Fair Value	7,662,000		7,638,000
Short-term investments
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 7,662,000		$ 7,638,000

Fair value disclosures - Assets

Fair value disclosures - Assets Measured at Fair Value on Recurring Basis (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Measurements, Recurring | Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, assets	$ 7,662,000	$ 7,638,000
Fair Value, Measurements, Recurring | Money market funds | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, assets	7,662,000	7,638,000
Fair Value, Measurements, Recurring | Money market funds | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, assets	0	0
Fair Value, Measurements, Recurring | Money market funds | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, assets	0	0
Fair Value, Measurements, Recurring | Mutual funds held in Rabbi Trust
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, assets	528,000	616,000
Fair Value, Measurements, Recurring | Mutual funds held in Rabbi Trust | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, assets	528,000	616,000
Fair Value, Measurements, Recurring | Mutual funds held in Rabbi Trust | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, assets	0	0
Fair Value, Measurements, Recurring | Mutual funds held in Rabbi Trust | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, assets	0	0
Fair Value, Measurements, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, assets	$ 0	$ 0

Asset Sale (Details)

Asset Sale (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Jan. 31, 2017	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Apr. 30, 2019	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restructuring charges		$ 0	$ 179
Gain within operating income				$ 900		$ 2,200
Transition services agreement receivable		11,680		11,861
Transition services agreement payables		11,759		$ 11,765
Other Current Liabilities | Indemnification Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset sale related contingent liabilities		$ 6,500
NeoPhotonics Corporation, LLC | Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percent of interest to be disposed					100.00%
Restructuring charges					$ 1,600
Accrued payment derivative					2,000
Assets-held-for sale					$ 3,000
Percent of ownership disposed							100.00%
Consideration received pursuant to asset purchase agreement							$ 2,000
Exit fee settlements							$ 2,000
Low Speed Transceiver Products | Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets-held-for sale								$ 13,900
Assets held for sale, inventory								13,100
Assets held for sale, property, plant and equipment								$ 800
Reclassification from assets held-for-sale	$ 3,400
Assets sold	12,800
Low Speed Transceiver Products | Disposed of by Sale | APAT OE
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received pursuant to asset purchase agreement	25,000
Proceeds from post-closing transaction services fees under transition services agreement	1,400
Disposal group consideration adjustment	21,600
Consideration adjustment for potential indemnification claims	10,000
Low Speed Transceiver Products | Disposed of by Sale | Inventories
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets sold	12,100
Low Speed Transceiver Products | Disposed of by Sale | Property, Plant and Equipment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets sold	$ 700

Balance sheet components - Acco

Balance sheet components - Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Accounts receivable	$ 61,914	$ 68,988
Trade notes receivable	0	156
Allowance for doubtful accounts	(251)	(254)
Account and trade note receivables, net	$ 61,663	$ 68,890

Balance sheet components - Inve

Balance sheet components - Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Raw materials	$ 21,987	$ 19,350
Work in process	13,957	12,262
Finished goods	10,202	15,318
Inventories	46,146	46,930
Finished goods, at vendor managed inventory locations	$ 1,500	$ 1,600

Balance sheet components - Prep

Balance sheet components - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Transition services agreement receivable (refer to Note 6)	$ 11,680	$ 11,861
Prepaid taxes and taxes receivable	3,569	6,979
Deposits and other prepaid expenses	2,620	2,512
Other receivable	8,309	4,499
Prepaid expenses and other current assets	$ 26,178	$ 25,851

Balance sheet components - Purc

Balance sheet components - Purchased Itangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Assets	$ 52,890	$ 53,191
Accumulated Amortization	(50,937)	(51,040)
Net Assets	1,953	2,151
Technology and patents
Finite-Lived Intangible Assets [Line Items]
Gross Assets	36,685	36,880
Accumulated Amortization	(35,537)	(35,555)
Net Assets	1,148	1,325
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Assets	15,004	15,089
Accumulated Amortization	(15,004)	(15,089)
Net Assets	0	0
Leasehold interest
Finite-Lived Intangible Assets [Line Items]
Gross Assets	1,201	1,222
Accumulated Amortization	(396)	(396)
Net Assets	$ 805	$ 826

Balance sheet components - Amor

Balance sheet components - Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Cost of goods sold	$ 184	$ 184
Operating expenses	0	119
Total	$ 184	$ 303

Balance sheet components - Esti

Balance sheet components - Estimated Future Amortization Expense of Purchased Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
2020 (remaining nine months)	$ 539
2021	644
2022	27
2023	27
2024	27
Thereafter	689
Net Assets	$ 1,953	$ 2,151

Balance sheet components - Accr

Balance sheet components - Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Employee-related	$ 19,706	$ 17,877
Transition services agreement payables (refer to Note 6)	11,759	11,765
Asset sale related warranty claims (refer to Note 6)	6,549	6,664
Operating lease liabilities, current	2,119	2,086
Income and other taxes payable	1,676	2,036
Accrued warranty	749	712	$ 739	$ 672
Other accrued expenses	6,152	6,341
Accrued and other current liabilities	$ 48,710	$ 47,481

Balance sheet components - Warr

Balance sheet components - Warranty Accrual (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward]
Beginning balance	$ 712	$ 672
Warranty accruals	225	315
Settlements	(188)	(248)
Ending balance	$ 749	$ 739

Balance sheet components - Othe

Balance sheet components - Other Noncurrent Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Pension and other employee-related	$ 3,958	$ 4,125
Asset retirement obligations	3,756	3,529
Deferred income tax liabilities	1,733	528
Government grant	1,172	1,380
Other	51	52
Other noncurrent liabilities	$ 10,670	$ 9,614

Debt - Components of Debt Oblig

Debt - Components of Debt Obligations and Weighted Average Interest Rate (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term debt, gross and lease obligation	$ 41,015	$ 42,452
Finance lease liability	254	275
Unaccreted discount and issuance costs	(412)	(446)
Current portion of long-term debt	3,066	3,044
Long-term debt, net of current portion	37,791	39,237
Total long-term debt, net of unaccreted discount and issuance costs	40,857	42,281
Line of Credit | Wells Fargo Credit Facility
Debt Instrument [Line Items]
Long-term debt, gross and lease obligation	$ 26,596	$ 27,329
Weighted average interest rate	2.93%	3.72%
Line of Credit | Mitsubishi Bank Loans | Minimum
Debt Instrument [Line Items]
Weighted average interest rate	1.05%	1.04%
Line of Credit | Mitsubishi Bank Loans | Maximum
Debt Instrument [Line Items]
Weighted average interest rate	1.45%	1.44%
Notes Payable to Banks | Mitsubishi Bank Loans
Debt Instrument [Line Items]
Long-term debt, gross and lease obligation	$ 8,803	$ 9,255
Notes Payable to Banks | Mitsubishi Bank Loans And Yamanashi Chuo Bank Loans
Debt Instrument [Line Items]
Long-term debt, gross and lease obligation	$ 5,616	$ 5,868
Weighted average interest rate	1.07%	1.07%

Debt - Notes Payable (Details)

Debt - Notes Payable (Details)	1 Months Ended		3 Months Ended
	May 31, 2018USD ($)	Nov. 30, 2017USD ($)	Mar. 31, 2020CNY (¥)line_of_credit	Mar. 31, 2020USD ($)line_of_credit	Dec. 31, 2019USD ($)
Notes Payable | Loans with Suppliers | Minimum
Debt Instrument [Line Items]
Debt instrument, term			3 months
Notes Payable | Loans with Suppliers | Maximum
Debt Instrument [Line Items]
Debt instrument, term			6 months
Loans Payable | First Credit Facility
Debt Instrument [Line Items]
Current borrowing capacity			¥ 120,000,000	$ 16,900,000
Loans Payable | Second Line of Credit
Debt Instrument [Line Items]
Current borrowing capacity			30,000,000	4,200,000
Bankers Acceptance
Debt Instrument [Line Items]
Restricted cash and investments, current				2,500,000	$ 2,500,000
Bankers Acceptance | Loans with Suppliers
Debt Instrument [Line Items]
Short-term debt				0	$ 0
Bankers Acceptance | First Credit Facility
Debt Instrument [Line Items]
Current borrowing capacity			¥ 240,000,000	33,900,000
Percentage of compensating balance requirement for bank acceptance drafts			50.00%
Bankers Acceptance | Second Line of Credit
Debt Instrument [Line Items]
Percentage of compensating balance requirement for bank acceptance drafts			50.00%
Short Term Loans | Second Line of Credit
Debt Instrument [Line Items]
Current borrowing capacity			¥ 60,000,000	$ 8,500,000
China | Notes Payable | First Credit Facility
Debt Instrument [Line Items]
Proceeds from lines of credit		$ 17,000,000
Repayments of lines of credit	$ 17,000,000
China | Bankers Acceptance | First Credit Facility
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage		4.10%
Line of Credit | China
Debt Instrument [Line Items]
Number of debt instruments | line_of_credit			2	2

Debt - Credit Facilities (Detai

Debt - Credit Facilities (Details) - Wells Fargo Credit Facility - USD ($)	1 Months Ended
	Jan. 31, 2019	Sep. 30, 2017	Mar. 31, 2020	Dec. 31, 2019	Jun. 14, 2019
Line of Credit Facility [Line Items]
Repayments of lines of credit	$ 5,000,000
Accrued interest			$ 300,000
Line of Credit
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing amount		$ 50,000,000
Cash balance for borrowing		100.00%
Cash balance max borrowing		$ 15,000,000
Line of credit facility increase		25,000,000
Line of credit facility, maximum indebtedness under debt covenant		20,000,000
Unused borrowing capacity		$ 5,000,000			$ 5,000,000
Line of credit fair value outstanding			$ 26,600,000
Weighted average interest rate			2.93%	3.72%
Unused part of credit facility			$ 7,100,000
Minimum required unused borrowing capacity			$ 5,000,000
Line of Credit | U.S.
Line of Credit Facility [Line Items]
Liquidity Requirements under Line of Credit Facility					30,000,000
Line of Credit | World Wide
Line of Credit Facility [Line Items]
Liquidity Requirements under Line of Credit Facility					$ 40,000,000
Line of Credit | Libor Plus Rate
Line of Credit Facility [Line Items]
Weighted average interest rate			2.93%
Line of Credit | Prime Rate
Line of Credit Facility [Line Items]
Commitment fee		0.25%
Line of Credit | Minimum
Line of Credit Facility [Line Items]
Revolver accounts receivable		80.00%
Line of Credit | Minimum | Libor Plus Rate
Line of Credit Facility [Line Items]
Debt instrument, basis spread		1.50%
Line of Credit | Minimum | Prime Rate
Line of Credit Facility [Line Items]
Debt instrument, basis spread		0.50%
Line of Credit | Maximum
Line of Credit Facility [Line Items]
Revolver accounts receivable		85.00%
Line of Credit | Maximum | Libor Plus Rate
Line of Credit Facility [Line Items]
Debt instrument, basis spread		1.75%
Line of Credit | Maximum | Prime Rate
Line of Credit Facility [Line Items]
Debt instrument, basis spread		0.75%

Debt - Mitsubishi Bank Loans (D

Debt - Mitsubishi Bank Loans (Details) $ in Millions	Feb. 25, 2015USD ($)	Feb. 25, 2015JPY (¥)	Jan. 31, 2018USD ($)	Jan. 31, 2018JPY (¥)	Mar. 31, 2017USD ($)	Mar. 31, 2020USD ($)	Mar. 31, 2020JPY (¥)	Mar. 31, 2017JPY (¥)	Feb. 25, 2015JPY (¥)
Notes Payable to Banks | Mitsubishi Bank Term Loan A
Debt Instrument [Line Items]
Debt, aggregate principal amount	$ 4.4								¥ 500,000,000
Notes Payable to Banks | Mitsubishi Bank Term Loan B
Debt Instrument [Line Items]
Debt, aggregate principal amount	9.2								¥ 1,000,000,000
Debt, periodic principal payments	0.1	¥ 8,300,000
Debt, lump sum payment on the maturity date	$ 0.1	¥ 8,400,000
Notes Payable to Banks | Mitsubishi Bank Term Loan B | Tokyo interbank offer rate
Debt Instrument [Line Items]
Debt instrument, basis spread	1.40%	1.40%
Notes Payable to Banks | Mitsubishi Bank Loans
Debt Instrument [Line Items]
Loan structuring fee including consumption tax	$ 0.4	¥ 40,500,000
Notes Payable to Banks | Mitsubishi Bank Loans | Tokyo interbank offer rate
Debt Instrument [Line Items]
Debt instrument, basis spread	1.40%	1.40%
Notes Payable to Banks | 2015 Mitsubishi Bank Loan
Debt Instrument [Line Items]
Long-term debt						$ 4.5	¥ 491,700,000
Notes Payable to Banks | 2017 Mitsubishi Bank Loan
Debt Instrument [Line Items]
Debt, aggregate principal amount					$ 6.4			¥ 690,000,000
Long-term debt						$ 4.3	¥ 460,000,000
Debt instrument, term					72 months
Line of credit facility, outstanding					$ 6.4			¥ 690,000,000
Notes Payable to Banks | 2017 Mitsubishi Bank Loan | Tokyo interbank offer rate
Debt Instrument [Line Items]
Debt instrument, basis spread					1.00%
Mitsubishi Bank | Mitsubishi Bank Term Loan A
Debt Instrument [Line Items]
Repayments of lines of credit			$ 4.4	¥ 500,000,000

Debt - Mitsubishi Bank and Yama

Debt - Mitsubishi Bank and Yamanashi Chuo Bank Loans (Details) - Mitsubishi Bank and The Yamanashi Chuo Bank, Ltd. - Term Loan C $ in Millions	1 Months Ended
	Jan. 31, 2018USD ($)	Mar. 31, 2020USD ($)	Mar. 31, 2020JPY (¥)	Jan. 31, 2018JPY (¥)
Debt Instrument [Line Items]
Credit facility, maximum borrowing amount	$ 7.9			¥ 850,000,000
Debt instrument, term	82 months
Long-term debt		$ 5.6	¥ 607,100,000
Tokyo interbank offer rate
Debt Instrument [Line Items]
Debt instrument, basis spread	1.00%

Debt - Maturities of Long-Term

Debt - Maturities of Long-Term debt (Details) $ in Thousands	Mar. 31, 2020USD ($)
Debt Disclosure [Abstract]
2020 (remaining nine months)	$ 2,334
2021	3,112
2022	29,708
2023	3,112
2024	2,314
Thereafter	435
Total long-term debt, current and non-current	$ 41,015

Leases - Narrative (Details)

Leases - Narrative (Details)	3 Months Ended
	Mar. 31, 2020
Lessee, Lease, Description [Line Items]
Termination period	1 year
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	7 years

Leases - Lease Cost (Details)

Leases - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Leases [Abstract]
Operating lease cost	$ 759	$ 754
Variable and short-term lease cost	403	348
Total lease cost	$ 1,162	$ 1,102

Leases - Cash Flows (Details)

Leases - Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Leases [Abstract]
Operating cash flows from operating leases	$ 718	$ 835
Right-of-use assets obtained in exchange for lease obligations: Operating leases	$ 0	$ 0
Weighted average remaining lease term, Operating leases	7 years 2 months 12 days	7 years 10 months 24 days
Weighted average discount rate, Operating leases	6.40%	6.40%

Leases - Leases, Liability, Mat

Leases - Leases, Liability, Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2020 (remaining nine months)	$ 2,423
2021	3,093
2022	3,089
2023	3,039
2024	2,943
Thereafter	8,266
Total future minimum lease payments	22,853
Less imputed interest	(4,736)
Total	$ 18,117	$ 18,629

Leases - Balance Sheet Informat

Leases - Balance Sheet Information (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating Leases, Accrued and other current liabilities	$ 2,119	$ 2,086
Operating Leases, Operating lease liabilities, noncurrent	15,998	16,543
Total	$ 18,117	$ 18,629

Japan pension plan (Details)

Japan pension plan (Details) - Japan - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Pension liability	$ 3.7	$ 4.1
Pension liability included in accrued and other current liabilities	$ 0.3	$ 0.6

Commitments and contingencies (

Commitments and contingencies (Details)

Mar. 31, 2020CNY (¥)

Mar. 31, 2020USD ($)

Oct. 25, 2017CNY (¥)

Oct. 25, 2017USD ($)

Jun. 16, 2017USD ($)

Dec. 27, 2016USD ($)

Aug. 31, 2019USD ($)

Mar. 31, 2019CNY (¥)

Mar. 31, 2019USD ($)

Feb. 28, 2019CNY (¥)

Feb. 28, 2019USD ($)

Jan. 31, 2019USD ($)

Dec. 31, 2018CNY (¥)lawsuit

Dec. 31, 2018USD ($)lawsuit

Nov. 30, 2018USD ($)

Jul. 31, 2018USD ($)

Apr. 30, 2018USD ($)

Mar. 31, 2020USD ($)

Dec. 31, 2010claimlawsuit

Commitments And Contingencies Disclosure [Line Items]

Number of defendants | lawsuit

4

Indemnification Agreement

Commitments And Contingencies Disclosure [Line Items]

Payment for legal settlement

$ 0

Finisar Corp

Commitments And Contingencies Disclosure [Line Items]

Pending claims | claim

2

Lestina International Ltd. litigation

Commitments And Contingencies Disclosure [Line Items]

Damages sought, value

$ 3,000,000

Lawsuit Filed by Lestina International Ltd. | NeoPhotonics Dongguan Co., Ltd | Lestina International Ltd.

Commitments And Contingencies Disclosure [Line Items]

Loss contingency, damages awarded, value

$ 2,200,000

APAT OE Legal Dispute

Commitments And Contingencies Disclosure [Line Items]

Damages sought, value

$ 20,000,000

APAT OE Legal Dispute | APAT OE

Commitments And Contingencies Disclosure [Line Items]

New claims filed, number | lawsuit

2

2

APAT OE and NeoChina

Commitments And Contingencies Disclosure [Line Items]

Damages sought, value

¥ 50,900,000

$ 7,600,000

Assets ordered to be preserved

$ 3,800,000

$ 29,000,000

Claim Against APAT OE and Zheijiang Merchants Property Insurance Company | NeoChina

Commitments And Contingencies Disclosure [Line Items]

Damages sought, value

¥ 350,000

$ 52,000

APAT Arbitration

Commitments And Contingencies Disclosure [Line Items]

Damages sought, value

$ 1,500,000

$ 8,100,000

$ 7,100,000

$ 7,800,000

$ 12,000,000

Damages awarded to company

¥ 700,000

$ 110,000

Attorney fees

¥ 846,000

$ 119,000

¥ 810,000

$ 121,000

APAT Arbitration | NeoChina

Commitments And Contingencies Disclosure [Line Items]

Loss contingency, damages awarded, value

¥ 54,607,000

$ 7,700,000

Stockholders' equity - Narrativ

Stockholders' equity - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Mar. 31, 2020
Class of Stock [Line Items]
Accumulated deficit subject to restriction	$ 9.2
Minimum
Class of Stock [Line Items]
Accumulated profits	10.00%
Employee stock options
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)		9,273,221
Employee stock purchase plan
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)		1,717,211

Stockholders' equity - Accumula

Stockholders' equity - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ (160,206)	$ (160,240)
Other comprehensive loss, net of taxes of zero	1,970	(2,937)
Ending balance	(167,238)	(152,558)
Other comprehensive loss, tax	0
Foreign Currency Translation Adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	7,641
Other comprehensive loss, net of taxes of zero	1,970
Ending balance	9,611
Defined Benefit Pension Plan Adjustment
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	230
Other comprehensive loss, net of taxes of zero	0
Ending balance	230
Accumulated other comprehensive loss
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	7,871	7,126
Ending balance	$ 9,841	$ 4,189

Restricted net assets (Details)

Restricted net assets (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted net assets in the Company's consolidated subsidiaries	$ 20,902	$ 21,096
Consolidated net assets	167,200	160,200
Cash restricted in China as a result of ongoing litigation and unfulfilled government grants
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted net assets in the Company's consolidated subsidiaries	10,896	10,936
China earnings restricted to fund statutory common reserves in China
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted net assets in the Company's consolidated subsidiaries	9,081	9,240
Loan agreements in Japan requiring local subsidiaries to maintain minimum net asset levels
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted net assets in the Company's consolidated subsidiaries	$ 925	$ 920

Stock-based compensation - Summ

Stock-based compensation - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	$ 2,518	$ 3,338
Cost of goods sold
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	537	601
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	758	881
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	530	678
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	$ 693	$ 1,178

Stock-based compensation - Valu

Stock-based compensation - Valuation Assumptions of Stock-based Awards (Details) - Market-based restricted stock units	3 Months Ended
	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average volatility	66.00%
Risk-free interest rate	2.79%
Expected dividends	0.00%

Stock-based compensation - Stoc

Stock-based compensation - Stock Options and RSUs (Details)	3 Months Ended
	Mar. 31, 2020$ / sharesshares
Employee stock options
Number of Shares
Beginning Balance (in shares) | shares	2,598,745
Granted (in shares) | shares	0
Exercised/Converted (in shares) | shares	(52,501)
Cancelled/Forfeited (in shares) | shares	(23,505)
Ending Balance (in shares) | shares	2,522,739
Weighted Average Exercise Price
Beginning Balance (in USD per share) | $ / shares	$ 5.93
Granted (in USD per share) | $ / shares	0
Exercised/Converted (in USD per share) | $ / shares	4.40
Cancelled/Forfeited (in USD per share) | $ / shares	11.15
Ending Balance (in USD per share) | $ / shares	$ 5.91
Restricted stock units
Number of Units
Beginning Balance (in shares) | shares	3,170,981
Granted (in shares) | shares	224,131
Exercised/Converted (in shares) | shares	(114,188)
Cancelled/Forfeited (in shares) | shares	(61,675)
Ending Balance (in shares) | shares	3,219,249
Weighted Average Exercise Price
Beginning Balance (in USD per share) | $ / shares	$ 5.80
Granted (in USD per share) | $ / shares	6.72
Exercised/Converted (in USD per share) | $ / shares	5.96
Cancelled/Forfeited (in USD per share) | $ / shares	6.10
Ending Balance (in USD per share) | $ / shares	$ 5.85

Stock-based compensation - Narr

Stock-based compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		12 Months Ended		27 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuence of shares (in shares)	0
Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense	$ 0.5				$ 0.5
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense	$ 11.7				$ 11.7
Awards granted in the period (in shares)	224,131
Shares vested (in shares)	114,188
Granted (in USD per share)	$ 6.72
Shares outstanding (in shares)	3,219,249		3,170,981		3,219,249
Market-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted in the period (in shares)					705,000
Shares vested (in shares)	0
Shares canceled (in shares)					93,500
Granted (in USD per share)			$ 4.86	$ 5.82
Unrecognized share based compensation	$ 1.1				$ 1.1
Compensation cost not yet recognized, period for recognition	1 year 3 months 18 days
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted in the period (in shares)	0	0
Shares outstanding (in shares)	153,404		163,471		153,404
SAU-related liabilities	$ 0.5		$ 0.8		$ 0.5
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense	$ 0.4				$ 0.4
Number of shares authorized for issuance (in shares)						1,500,000

Income taxes - Provision for In

Income taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income tax provision	$ (1,993)	$ (170)

Subsequent events (Details)

Subsequent events (Details)	Apr. 14, 2020shares
2020 Plan | Subsequent Event
Subsequent Event [Line Items]
Shares authorized for issuance (in shares)	2,121,414