Neophotonics (NPTN) 10-Q 4 Nov 21 2021 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2021	Oct. 28, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
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	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		52,695,368
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001227025
Current Fiscal Year End Date	--12-31

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 76,578	$ 95,117
Short-term investments	27,674	27,669
Restricted cash	495	489
Accounts receivable, net	57,901	45,232
Inventories	48,663	46,901
Prepaid expenses and other current assets	18,673	20,173
Total current assets	229,984	235,581
Property, plant and equipment, net	57,134	66,765
Operating lease right-of-use assets	13,922	13,823
Purchased intangible assets, net	985	1,468
Goodwill	1,115	1,115
Other long-term assets	5,159	4,912
Total assets	308,299	323,664
Current liabilities:
Accounts payable	59,303	43,539
Short-term borrowing, net	14,822	0
Current portion of long-term debt	3,015	3,232
Accrued and other current liabilities	24,983	42,053
Total current liabilities	102,123	88,824
Long-term debt, net of current portion	26,570	30,327
Operating lease liabilities, noncurrent	14,150	14,522
Other noncurrent liabilities	8,315	9,584
Total liabilities	151,158	143,257
Commitments and contingencies (Note 10)
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; at September 30, 2021, 52,659 shares issued and outstanding; at December 31, 2020, 50,457 shares issued and outstanding	132	126
Additional paid-in capital	604,727	597,460
Accumulated other comprehensive income	1,180	1,735
Accumulated deficit	(448,898)	(418,914)
Total stockholders’ equity	157,141	180,407
Total liabilities and stockholders’ equity	$ 308,299	$ 323,664

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
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)	52,659,000	50,457,000
Common stock, shares outstanding (in shares)	52,659,000	50,457,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenue	$ 83,742	$ 102,398	$ 209,677	$ 302,970
Cost of goods sold	59,968	77,994	162,689	215,338
Gross profit	23,774	24,404	46,988	87,632
Operating expenses:
Research and development	13,875	15,276	42,383	40,849
Sales and marketing	3,498	3,692	10,725	11,630
General and administrative	7,719	7,758	22,411	23,350
Acquisition and asset sale related costs	28	87	155	219
Restructuring charges (recoveries)	(12)	141	10	141
Total operating expenses	25,108	26,954	75,684	76,189
Income (loss) from operations	(1,334)	(2,550)	(28,696)	11,443
Interest income	94	21	339	141
Interest expense	(207)	(263)	(654)	(942)
Other income (expense), net	43	(3,317)	306	(2,314)
Total interest and other income expense, net	(70)	(3,559)	(9)	(3,115)
Income (loss) before income taxes	(1,404)	(6,109)	(28,705)	8,328
Income tax (provision) benefit	(456)	1,206	(1,279)	(1,199)
Net income (loss)	$ (1,860)	$ (4,903)	$ (29,984)	$ 7,129
Basic net income (loss) per share (in dollars per share)	$ (0.04)	$ (0.10)	$ (0.58)	$ 0.14
Diluted net income (loss) per share (in dollars per share)	$ (0.04)	$ (0.10)	$ (0.58)	$ 0.14
Weighted average shares used to compute basic net income (loss) per share (in shares)	52,427	49,936	51,599	49,212
Weighted average shares used to compute diluted net income (loss) per share (in shares)	52,427	49,936	51,599	51,411

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (1,860)	$ (4,903)	$ (29,984)	$ 7,129
Other comprehensive income (loss):
Foreign currency translation adjustments, net of zero tax	(243)	5,317	(555)	3,808
Total other comprehensive income (loss)	(243)	5,317	(555)	3,808
Comprehensive income (loss)	$ (2,103)	$ 414	$ (30,539)	$ 10,937

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) (Parenthetical) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustments, tax	$ 0	$ 0	$ 0	$ 0

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Accumulated deficit
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)	10,937			3,808	7,129
Issuance of common stock upon exercise of stock options (in shares)		322
Issuance of common stock upon exercise of stock options	1,387	$ 1	1,386
Issuance of common stock under employee stock purchase plan (in shares)		204
Issuance of common stock under employee stock purchase plan	1,332	$ 1	1,331
Issuance of common stock for vested restricted stock units (in shares)		1,288
Issuance of common stock for vested restricted stock units	0	$ 3	(3)
Tax withholding related to vesting of restricted stock units (in shares)		(202)
Tax withholding related to vesting of restricted stock units	(1,722)	$ (1)	(1,721)
Stock-based compensation costs	9,378		9,378
Ending Balance (in shares) at Sep. 30, 2020		50,138
Ending balance at Sep. 30, 2020	181,518	$ 125	592,875	(4,063)	(407,419)
Beginning balance (in shares) at Jun. 30, 2020		49,547
Beginning balance at Jun. 30, 2020	179,028	$ 124	590,800	(9,380)	(402,516)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	414			5,317	(4,903)
Issuance of common stock upon exercise of stock options (in shares)		7
Issuance of common stock upon exercise of stock options	40		40
Issuance of common stock for vested restricted stock units (in shares)		690
Issuance of common stock for vested restricted stock units	0	$ 2	(2)
Tax withholding related to vesting of restricted stock units (in shares)		(106)
Tax withholding related to vesting of restricted stock units	(936)	$ (1)	(935)
Stock-based compensation costs	2,972		2,972
Ending Balance (in shares) at Sep. 30, 2020		50,138
Ending balance at Sep. 30, 2020	181,518	$ 125	592,875	(4,063)	(407,419)
Beginning balance (in shares) at Dec. 31, 2020		50,457
Beginning balance at Dec. 31, 2020	180,407	$ 126	597,460	1,735	(418,914)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	(30,539)			(555)	(29,984)
Issuance of common stock upon exercise of stock options (in shares)		529
Issuance of common stock upon exercise of stock options	2,967	$ 1	2,966
Issuance of common stock under employee stock purchase plan (in shares)		235
Issuance of common stock under employee stock purchase plan	1,549	$ 1	1,548
Issuance of common stock for vested restricted stock units (in shares)		1,883
Issuance of common stock for vested restricted stock units	0	$ 5	(5)
Tax withholding related to vesting of restricted stock units (in shares)		(445)
Tax withholding related to vesting of restricted stock units	(4,952)	$ (1)	(4,951)
Stock-based compensation costs	7,709		7,709
Ending Balance (in shares) at Sep. 30, 2021		52,659
Ending balance at Sep. 30, 2021	157,141	$ 132	604,727	1,180	(448,898)
Beginning balance (in shares) at Jun. 30, 2021		52,080
Beginning balance at Jun. 30, 2021	157,392	$ 130	602,877	1,423	(447,038)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	(2,103)			(243)	(1,860)
Issuance of common stock upon exercise of stock options (in shares)		131
Issuance of common stock upon exercise of stock options	812		812
Issuance of common stock for vested restricted stock units (in shares)		578
Issuance of common stock for vested restricted stock units	0	$ 2	(2)
Tax withholding related to vesting of restricted stock units (in shares)		(130)
Tax withholding related to vesting of restricted stock units	(1,269)		(1,269)
Stock-based compensation costs	2,309		2,309
Ending Balance (in shares) at Sep. 30, 2021		52,659
Ending balance at Sep. 30, 2021	$ 157,141	$ 132	$ 604,727	$ 1,180	$ (448,898)

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net income (loss)	$ (29,984)	$ 7,129
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	18,220	24,096
Stock-based compensation expense	7,811	9,078
Deferred taxes	960	(4)
Others	248	269
Gain on sale of assets and other write-offs	33	(47)
Allowance for doubtful accounts	(1)	(16)
Write-down of inventories	9,215	7,236
Amortization of operating lease right-of-use assets	1,549	1,415
Foreign currency remeasurement	(110)	2,309
Change in operating assets and liabilities:
Accounts receivable	(12,671)	8,790
Inventories	(11,438)	(6,592)
Prepaid expenses and other assets	(582)	(1,315)
Accounts payable	15,587	(4,052)
Accrued and other liabilities	(20,454)	1,218
Net cash provided by (used in) operating activities	(21,617)	49,514
Cash flows from investing activities
Purchase of property, plant and equipment	(9,150)	(9,243)
Proceeds from sale of property, plant and equipment and other assets	1,023	507
Purchase of marketable securities	(27,506)	(23,529)
Proceeds from sale of marketable securities	27,501	3,500
Net cash used in investing activities	(8,132)	(28,765)
Cash flows from financing activities
Proceeds from exercise of stock options and issuance of stock under ESPP	4,946	2,719
Tax withholding on restricted stock units	(4,952)	(1,722)
Proceeds from bank loans, net of debt issuance costs	14,979	0
Repayment of bank loans	(3,626)	(8,349)
Repayment of finance lease liabilities	(70)	(64)
Net cash provided by (used in) financing activities	11,277	(7,416)
Effect of exchange rates on cash, cash equivalents and restricted cash	(61)	502
Net increase (decrease) in cash, cash equivalents and restricted cash	(18,533)	13,835
Cash, cash equivalents and restricted cash at the beginning of the period	95,606	81,439
Cash, cash equivalents and restricted cash at the end of the period	77,073	95,274
Supplemental disclosure of non-cash investing and financing activities:
Unpaid property, plant and equipment in accounts payable	1,192	1,811
Right-of-use asset in exchange for a lease liability	$ 1,639	$ 0

Basis of presentation and signi

Basis of presentation and significant accounting policies	9 Months Ended
	Sep. 30, 2021
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 September 30, 2021 and for the three and nine months ended September 30, 2021 and 2020, 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. These condensed consolidated financial statements do not include all disclosures required by U.S. generally accepted accounting principles (“U.S. GAAP”) and should be read in conjunction with the Consolidated Financial Statements and Notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020. The results of operations for the three and nine months ended September 30, 2021 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 state of the global semiconductor market and supply chain; the successful and timely completion of product design efforts; the ability of the Company to sell its new products into new market segments; the general state of the U.S., China and world economies; the highly cyclical nature of the industries the Company serves; trade restrictions by the United States against the Company's customers in China, as well as potential retaliatory trade actions taken by China; the loss of any of its larger customers; restrictions on the Company's ability to sell to foreign customers due to additional U.S. or new China 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; 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, 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, future adverse developments with respect to the Covid-19 pandemic may have a negative impact on its sales, supply chain and results of operations. The inputs into the Company's judgments and estimates also consider the Department of Commerce Entities List restrictions on Huawei Technologies effective September 2020 for the Company and loss of business from Huawei Technologies. Concentration In the three months ended September 30, 2021, three customers were each greater than 10% of the Company’s total revenue, representing 60% of total revenue, and the Company's top five customers represented approximately 79% of the Company’s total revenue. In the three months ended September 30, 2020, three customers each were greater than 10% of revenue, representing 71% of total revenue, and our top five customers during this period represented 82% of total revenue. In the nine months ended September 30, 2021, four customers were each greater than 10% of the Company's total revenue, representing 67% of total revenue, and the Company's top five customers represented approximately 77% of the total revenue. In the nine months ended September 30, 2020, two customers each were greater than 10% of the Company's total revenue, representing 67% of total revenue, and the Company’s top five customers represented 82% of the Company’s total revenue. As of September 30, 2021, four customers accounted for a total of 65% of the Company’s total accounts receivable. As of December 31, 2020, three customers accounted for a total of 65% of the Company’s total 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 and recoverability of long-lived assets; valuation allowances for deferred tax assets; valuation of excess and obsolete inventories; warranty reserves; and recognition of stock-based compensation, among others. Actual results could differ from these estimates. Long-lived Assets The Company assesses the impairment of long-lived assets whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. An impairment loss would be recognized when the sum of the future net cash flows expected to result from the use of the asset and its eventual disposition is less than its carrying amount. The estimated future cash flows are based upon, among other things, assumptions about expected future operating performance and may differ from actual cash flows. Due to the additional restrictions imposed by the U.S. Bureau of Industry and Security ("BIS"), an agency of the U.S. Department of Commerce, which became effective in September 2020, and the expected loss of business from Huawei, the Company performed a recoverability test in the third and fourth quarters of 2020 and determined there was no impairment of long-lived assets. 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 December 2019, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (ASU 2019-12), which simplifies the accounting for income taxes. This guidance became effective for fiscal years beginning after December 15, 2020. The Company adopted this ASU in the first quarter of 2021 and the adoption of this standard did not have a material impact on the Company's consolidated financial statements. 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	9 Months Ended
	Sep. 30, 2021
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 optoelectronic laser, component and module 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 the 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 Nine Months Ended 2021 2020 2021 2020 High Speed Products $ 78,383 $ 94,532 $ 196,688 $ 277,245 Network Products and Solutions 5,359 7,866 12,989 25,725 Total revenue $ 83,742 $ 102,398 $ 209,677 $ 302,970 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 Nine Months Ended 2021 2020 2021 2020 China $ 26,026 $ 57,087 $ 66,209 $ 178,661 Americas 10,561 17,201 21,750 51,622 Rest of world 47,155 28,110 121,718 72,687 Total revenue $ 83,742 $ 102,398 $ 209,677 $ 302,970 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 September 30, 2021 and December 31, 2020. 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 September 30, 2021 and December 31, 2020. 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 September 30, 2021 and December 31, 2020 were immaterial.

Net income (loss) per share

Net income (loss) per share	9 Months Ended
	Sep. 30, 2021
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 Nine Months Ended 2021 2020 2021 2020 Numerator: Net income (loss) $ (1,860) $ (4,903) $ (29,984) $ 7,129 Denominator: Weighted average shares used to compute per share amount: Basic 52,427 49,936 51,599 49,212 Diluted 52,427 49,936 51,599 51,411 Basic net income (loss) per share $ (0.04) $ (0.10) $ (0.58) $ 0.14 Diluted net income (loss) per share $ (0.04) $ (0.10) $ (0.58) $ 0.14 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 Nine Months Ended 2021 2020 2021 2020 Employee stock options 1,604 2,282 1,604 658 Restricted stock units 3,274 3,622 3,274 80 Market-based restricted stock units 134 612 134 612 Performance-based restricted stock units 240 90 240 90 Employee stock purchase plan 125 169 125 — 5,377 6,775 5,377 1,440

Cash, cash equivalents, short-t

Cash, cash equivalents, short-term investments, and restricted cash	9 Months Ended
	Sep. 30, 2021
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): September 30, 2021 December 31, 2020 Cash and cash equivalents $ 76,578 $ 95,117 Restricted cash 495 489 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 77,073 $ 95,606 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 September 30, 2021 As of December 31, 2020 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 $ 27,674 $ — $ — $ 27,674 $ 27,669 $ — $ — $ 27,669 Reported as: Short-term investments $ 27,674 $ 27,669 As of September 30, 2021 and December 31, 2020, maturities of marketable securities were less than one year. There were no realized gains and losses on the sale of marketable securities during the three and nine months ended September 30, 2021 and 2020. The Company did not recognize any impairment losses on its marketable securities during the three and nine months ended September 30, 2021 or 2020. As of September 30, 2021, 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	9 Months Ended
	Sep. 30, 2021
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 September 30, 2021 As of December 31, 2020 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Short-term investments: Money market funds $ 27,674 $ — $ — $ 27,674 $ 27,669 $ — $ — $ 27,669 Other long-term assets: Mutual funds held in Rabbi Trust $ 847 $ — $ — $ 847 $ 810 $ — $ — $ 810 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 September 30, 2021. 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 September 30, 2021 and December 31, 2020. There were no liabilities that are measured at fair value on a recurring basis as of September 30, 2021. Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis As of September 30, 2021 and December 31, 2020 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

Balance sheet components

Balance sheet components	9 Months Ended
	Sep. 30, 2021
Balance Sheet Related Disclosures [Abstract]
Balance sheet components	Balance sheet components Accounts receivable, net Accounts receivable, net, consists of the following (in thousands): September 30, 2021 December 31, 2020 Accounts receivable $ 57,901 $ 45,277 Allowance for doubtful accounts — (45) $ 57,901 $ 45,232 Inventories Inventories consist of the following (in thousands): September 30, 2021 December 31, 2020 Raw materials $ 27,699 $ 25,620 Work in process 14,105 9,196 Finished goods (1) 6,859 12,085 $ 48,663 $ 46,901 ________________________________________________________ (1) Finished goods inventory at customer vendor managed inventory locations was $1.8 million and $1.7 million as of September 30, 2021 and December 31, 2020, respectively. Prepaid expenses and other current assets Prepaid expenses and other current assets consist of the following (in thousands): September 30, 2021 December 31, 2020 Transition services agreement receivable (refer to Note 10) $ — $ 5,933 Prepaid taxes and taxes receivable 5,247 6,137 Receivables due from suppliers 10,009 4,891 Deposits and other prepaid expenses 2,869 2,417 Other receivable 548 795 $ 18,673 $ 20,173 Purchased intangible assets, net Purchased intangible assets, net, consist of the following (in thousands): September 30, 2021 December 31, 2020 Gross Accumulated Net Gross Accumulated Net Technology and patents $ 37,777 $ (37,631) $ 146 $ 37,637 $ (37,021) $ 616 Customer relationships 15,476 (15,476) — 15,487 (15,487) — Leasehold interest 1,319 (480) 839 1,304 (452) 852 $ 54,572 $ (53,587) $ 985 $ 54,428 $ (52,960) $ 1,468 For the three months ended September 30, 2021 and 2020, amortization expense relating to technology and patents is included within cost of goods sold and totaled $0.2 million in each period. For the nine months ended September 30, 2021 and 2020, amortization expense relating to technology and patents is included within cost of goods sold and totaled $0.5 million and $0.6 million, respectively. The estimated future amortization expense of purchased intangible assets as of September 30, 2021, was as follows (in thousands): 2021 (remaining three months) $ 149 2022 10 2023 10 2024 10 2025 10 Thereafter 796 $ 985 Accrued and other current liabilities Accrued and other current liabilities consist of the following (in thousands): September 30, 2021 December 31, 2020 Employee-related $ 13,155 $ 19,656 Transition services agreement payables (refer to Note 10) 823 9,708 Operating lease liabilities, current 2,515 2,128 Income and other taxes payable 1,620 1,590 Accrued warranty 843 1,111 Other accrued expenses 6,027 7,860 $ 24,983 $ 42,053 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 Nine Months Ended 2021 2020 2021 2020 Beginning balance $ 903 $ 1,617 $ 1,111 $ 712 Warranty accruals 107 369 172 1,605 Settlements (167) (573) (440) (904) Ending balance $ 843 $ 1,413 $ 843 $ 1,413 Other noncurrent liabilities Other noncurrent liabilities consist of the following (in thousands): September 30, 2021 December 31, 2020 Pension and other employee-related $ 3,490 $ 3,844 Asset retirement obligations 3,887 3,810 Transition services agreement payables (See Note 10) — 823 Deferred income tax liabilities 507 501 Government grant 431 606 $ 8,315 $ 9,584

Debt

Debt	9 Months Ended
	Sep. 30, 2021
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): September 30, 2021 December 31, 2020 Carrying Interest Carrying Interest Short-term borrowing: Note payable to Shanghai Pudong Development Bank $ 15,000 0.60 % $ — — % Unaccreted discount and issuance costs (178) — Short-term borrowing, net $ 14,822 $ — Long-term debt, current and noncurrent: Borrowing under Wells Fargo Credit Facility $ 20,241 1.90 % $ 21,030 2.01 % Mitsubishi Bank loans 5,633 1.07% -1.47% 7,662 1.05%-1.45% Mitsubishi Bank and Yamanashi Chuo Bank loan 3,805 1.07 % 5,002 1.07 % Finance lease liability 118 189 Total long-term debt 29,797 33,883 Unaccreted discount and issuance costs (212) (324) Total long-term debt, net of unaccreted discount and issuance costs $ 29,585 $ 33,559 Reported as: Current portion of long-term debt $ 3,015 $ 3,232 Long-term debt, net of current portion 26,570 30,327 Total long-term debt, net of unaccreted discount and issuance costs $ 29,585 $ 33,559 Notes payable and short-term borrowing In June 2021, NeoPhotonics (China) Co., Ltd., ("NeoPhotonics China"), a subsidiary of the Company, entered into a credit line agreement with Shanghai Pudong Development Bank Shenzhen Branch (“SPDB”) providing for a line of credit to NeoPhotonics China in an amount of RMB 120,000,000 (approximately $18.6 million) for short-term loans at varying interest rates. In June 2021, NeoPhotonics Dongguan Co., Ltd (“NeoPhotonics Dongguan”), also a subsidiary of the Company, entered into a credit line agreement with SPDB providing for a line of credit to NeoPhotonics Dongguan in an amount of RMB 30,000,000 (approximately $4.6 million) for short-term loans at varying interest rates. As of September 30, 2021, there was not an amount outstanding under this credit facility. 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 As of September 30, 2021 and December 31, 2020, there was $15.0 million and $0 outstanding under the NeoPhotonics China credit facility, respectively. The note payable bears interest at 3.0% (2.4% of which was charged to NeoPhotonics China as a loan fee and will be paid in the fourth quarter of 2021). This note matures in March 2022. As of September 30, 2021 and December 31, 2020, there were no bank acceptance drafts issued in connection under the NeoPhotonics Dongguan credit facility. There were no compensating balances relating to these credit facilities as of September 30, 2021 and December 31, 2020, respectively. Compensating balances are classified as restricted cash on the Company’s condensed consolidated balance sheets. Credit facilities In June 2021, the Company entered into an Amended and Restated Credit Agreement (the “A&R Credit Agreement”) with Wells Fargo Bank, National Association ("Wells Fargo"), as administrative agent for a lender group. The A&R Credit Agreement amends and restates in full that certain Credit Agreement dated as of September 8, 2017 (as amended, the "Former Credit Agreement"), by and among the Company and Wells Fargo. The A&R Credit Agreement provides for continuation of the $50 million revolving credit facility (the "Credit Facility"). Prior to the signing of the A&R Credit Agreement, the Company had drawn $21 million under the Former Credit Agreement, which amount was rolled over and is now treated as outstanding under the Credit Facility. The Credit Facility provides for borrowings equal to the lower of (a) a maximum revolver amount of $50.0 million, or (b) an amount up to 90% 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, 2026 and borrowings bear interest, at the Company's options, at an interest rate of either (a) the LIBOR rate, plus an applicable margin ranging from 1.50% to 1.75% per annum, based upon the average excess availability (as defined in the Credit Facility), or (b) the prime lending rate, plus an applicable margin ranging from 0.50% to 0.75% per annum, based upon the average excess availability. The Company is also required to pay a commitment fee equal to 0.25% of the unused portion of the Credit Facility, monthly, in arrears. The Credit Facility requires a mandatory 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, to 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. The Company was in compliance with the covenants of the Credit Facility as of September 30, 2021 and December 31, 2020 (under the terms of the Former Credit Agreement). As of September 30, 2021, the outstanding balance under the Credit Facility was $20.2 million and the weighted average rate under the LIBOR option was 1.90%. The remaining borrowing capacity as of September 30, 2021 was $15.9 million, of which $5.0 million is required to be maintained as unused borrowing capacity. During the three months ended September 30, 2021, $0.1 million of accrued interest was included as a component of 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 $9.0 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 September 30, 2021 and December 31, 2020. Outstanding principal balance for the Mitsubishi Term Loans was 341.7 million JPY (approximately $3.1 million) as of September 30, 2021. 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 $6.2 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 September 30, 2021 and December 31, 2020. The loan was available from March 31, 2017 to March 30, 2018 and 690.0 million JPY (approximately $6.2 million) under this loan was fully drawn in March 2017. Outstanding principal balance for the 2017 Mitsubishi Bank Loan was approximately 287.5 million JPY (approximately $2.6 million) as of September 30, 2021. 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 $7.6 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 September 30, 2021 and December 31, 2020. Outstanding principal balance for the Mitsubishi Bank and Yamanashi Chuo Bank Loan was approximately 425.0 million JPY (approximately $3.8 million) as of September 30, 2021. As of September 30, 2021, maturities of notes payable and borrowings under line of credit are as follows (in thousands): 2021 (remaining three months) $ 853 2022 18,029 2023 3,011 2024 2,241 2025 422 Thereafter 20,241 $ 44,797

Leases

Leases	9 Months Ended
	Sep. 30, 2021
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 September 30, 2021 and December 31, 2020, 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 Nine Months Ended 2021 2020 2021 2020 Operating lease cost $ 792 $ 757 $ 2,348 $ 2,273 Variable and short-term lease cost 774 574 2,074 1,472 Total lease cost $ 1,566 $ 1,331 $ 4,422 $ 3,745 Other information related to leases was as follows (in thousands, except lease term and discount rate): Nine Months Ended 2021 2020 Supplemental cash flow information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 2,493 $ 2,359 Weighted average remaining lease term Operating leases 5.7 years 6.7 years Weighted average discount rate Operating leases 6.3 % 6.5 % Future minimum lease payments under non-cancelable leases as of September 30, 2021 were as follows (in thousands): Operating Leases 2021 (remaining three months) $ 901 2022 3,465 2023 3,445 2024 3,345 2025 3,422 Thereafter 5,406 Total future minimum lease payments 19,984 Less imputed interest (3,319) Total $ 16,665 As of September 30, 2021 and December 31, 2020, the future minimum lease payments are captured in the Company's Consolidated Balance Sheets as follows: Operating Leases: September 30, 2021 December 31, 2020 Accrued and other current liabilities $ 2,515 $ 2,128 Operating lease liabilities, noncurrent 14,150 14,522 Total $ 16,665 $ 16,650

Japan pension plan

Japan pension plan	9 Months Ended
	Sep. 30, 2021
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 September 30, 2021 was $2.9 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, 2020 was $3.7 million, of which $0.7 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 and nine months ended September 30, 2021 and 2020.

Commitments and contingencies

Commitments and contingencies	9 Months Ended
	Sep. 30, 2021
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), except for the matter discussed in the following paragraph, that 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 (acquired by II-VI, Inc. in September 2019) ("Finisar"), filed a complaint in the U.S. District Court for the Northern District of California, 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 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 estimate a range of possible loss. APAT Litigation and Settlement Since April 2018, APAT OE and NeoPhotonics (China) Co., Ltd. and NeoPhotonics Dongguan Co. Ltd. (collectively "NeoChina", which are both wholly-owned subsidiaries of the Company) and NeoPhotonics Corporation was involved in a series of litigations and arbitrations which arose out of the 2017 sale by NeoChina of certain low speed transceiver assets to APAT. On October 27, 2020, the parties entered into a settlement agreement to settle all claims and release all property preservation orders. In exchange for a full release of all claims by all parties, terms of the settlement agreement include the following: i) APAT OE to pay NeoChina the arbitration awards in the amount of RMB 52,014,519 (approximately $7.6 million) plus interest of RMB 6,122,150 (approximately $0.9 million) for a total amount of RMB 58,136,669 (approximately $8.5 million) and ii) NeoPhotonics Corporation to pay APAT Hong Kong, a wholly-owned subsidiary of APAT OE, $10,031,515 plus $500,000 in interest for a total payment $10,531,515 for amounts that were paid by customers to NeoPhotonics Corporation for sales of products made by APAT OE after the close of the asset purchase agreement. In accordance with the settlement agreement, the first payment from APAT OE to the Company occurred in November 2020. All other payments between the parties, except the final payment, were completed in the first quarter of 2021 with the final payment by the Company to APAT expected to occur in first quarter of 2022. The settlement award of RMB 58,136,669 (approximately $8.5 million) payable by APAT OE to the Company represents repayment of the net receivables owed to the Company at the settlement date and partial recovery of previously recognized losses incurred by the Company of approximately $3.0 million primarily related to a litigation settlement loss with a vendor for committed purchases of certain production materials for which the liabilities were assumed by APAT OE in the Asset Purchase Agreement entered into with the Company in December 2016 and the legal fees incurred for the lawsuits with APAT OE during 2018, 2019 and 2020. At September 30, 2021, the amount payable by the Company to APAT OE under the settlement agreement is approximately $0.8 million, and is included in Accrued and Other Liabilities in the caption "Transition Services Agreement Payable" (See Note 6). APAT OE has repaid the full amount of the Transition Services Agreement Receivable owed to the Company and there is currently no balance remaining as of September 30, 2021 (See Note 6). 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	9 Months Ended
	Sep. 30, 2021
Stockholders' Equity Note [Abstract]
Stockholders’ equity	Stockholders’ equity Common Stock As of September 30, 2021, the Company had reserved 6,694,262 common stock for issuance under its equity incentive plans and 1,156,415 common stock shares for issuance under its employee stock purchase plan. Accumulated Other Comprehensive Loss The components of accumulated other comprehensive income (loss), net of related taxes, were as follows (in thousands): Foreign Currency Translation Adjustments Defined Benefit Pension Plan Adjustment Total Accumulated Other Comprehensive Income (Loss) Balance as of December 31, 2020 $ 1,951 $ (216) $ 1,735 Other comprehensive loss, net of taxes of zero (555) — (555) Balances at September 30, 2021 $ 1,396 $ (216) $ 1,180 No material amounts were reclassified out of accumulated other comprehensive loss during the three and nine months ended September 30, 2021 and 2020 for realized gains or losses on available-for-sale securities. Accumulated Deficit Approximately $10.0 million of the Company’s retained earnings within its total accumulated deficit as of December 31, 2020 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	9 Months Ended
	Sep. 30, 2021
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 September 30, 2021 and December 31, 2020, the Company's consolidated subsidiaries had $11.5 million and $11.4 million, respectively, of restricted net assets. This compares to the Company's consolidated net assets of $157.1 million and $180.4 million as of September 30, 2021 and December 31, 2020, respectively, which consisted of (in thousands): September 30, 2021 December 31, 2020 Cash restricted in China as a result of unfulfilled government grants $ 458 $ 452 China earnings restricted to fund statutory common reserves in China 10,125 10,010 Loan agreements in Japan requiring local subsidiaries to maintain minimum net asset levels 895 969 Total restricted net assets in the Company's consolidated subsidiaries $ 11,478 $ 11,431

Stock-based compensation

Stock-based compensation	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Stock-based compensation	Stock-based compensation The following table summarizes the stock-based compensation expense recognized in the three and nine months ended September 30, 2021 and 2020 (in thousands): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Cost of goods sold $ 403 $ 607 $ 1,523 $ 1,765 Research and development 565 748 2,171 2,505 Sales and marketing 353 565 1,168 1,833 General and administrative 873 853 2,949 2,975 $ 2,194 $ 2,773 $ 7,811 $ 9,078 As of September 30, 2021 and December 31, 2020, stock-based compensation capitalized in inventories totaled $0.2 million and $0.3 million, respectively. 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 and performance-based RSUs, during the three and nine months ended September 30, 2021: Stock Options Restricted Stock Units Number of Number of Balance as of December 31, 2020 2,096,917 3,621,681 Granted 60,944 1,434,500 Exercised/Converted (529,482) (1,445,813) Cancelled/Forfeited (24,393) (336,294) Balances at September 30, 2021 1,603,986 3,274,074 At September 30, 2021, the Company had $0.3 million of unrecognized stock-based compensation expense for stock options, net of estimated forfeitures. At September 30, 2021, the Company had $19.4 million of unrecognized stock-based compensation expense for RSUs, excluding market and performance-based RSUs, net of estimated forfeitures. Market-based Restricted Stock Units As of September 30, 2021, the Company has granted 705,000 shares of market-based RSUs and 133,875 shares remain outstanding 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. A total of 437,125 market-based RSUs have vested and 134,000 market-based RSUs have been cancelled/forfeited through September 30, 2021. As of September 30, 2021, the Company had $0.2 million of unrecognized stock-based compensation expense for these RSUs, net of estimated forfeitures. The fair value of market-based RSUs was measured on the grant date using Monte Carlo simulation model with the following assumptions: Assumptions Weighted-average volatility 66% Risk-free interest rate 2.79% Expected dividends —% Performance-based Restricted Stock Units In April 2020, the Company granted 90,400 shares of performance-based RSUs to certain employees. These RSUs will vest upon certification by the Board of Directors or the Compensation Committee that the Company has achieved at least $425 million in revenue over four consecutive fiscal quarters and the recipients remain in continuous service with the Company through such service period. None of these performance-based RSUs were vested through September 30, 2021. In July 2021, the Company granted 165,000 shares of performance-based RSUs to certain employees. These RSUs will vest upon certification by the Board of Directors or the Compensation Committee that the Company has achieved at least $100 million in revenue from Data Center Customers as measured over four consecutive quarters and the recipients remain in continuous service with the Company through such service period. None of such performance-based RSUs were vested through September 30, 2021, and 14,950 of these performance-based RSUs have been cancelled/forfeited through September 30, 2021. Stock Appreciation Units (SAUs) 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 and nine months ended September 30, 2021 or 2020. As of September 30, 2021 and December 31, 2020, there were 150,000 SAUs outstanding, respectively, and related SAU liabilities were $0.6 million and $0.7 million, respectively. Employee Stock Purchase Plan (ESPP) The Company did not issue shares under the ESPP during the three months ended September 30, 2021. As of September 30, 2021, there was $0.1 million of unrecognized stock-based compensation expense for employee stock purchase rights that will be recognized over the remaining offering period through November 2021. 2020 Equity Incentive Plan On June 1, 2021, at the 2021 Annual Meeting of Stockholders of NeoPhotonics Corporation, the Company's stockholders approved NeoPhotonics Corporation 2020 Equity Incentive Plan as amended and restated (the “Amended 2020 Plan”) to increase the number of shares available for the grant of stock options, restricted stock unit awards, and other awards by 900,000 shares. The Amended 2020 Plan became effective immediately upon stockholder approval at the Annual Meeting. After taking this amendment into account, the aggregate number of shares of common stock reserved for issuance under the Amended 2020 Plan will not exceed the sum of (i) 2,821,414 shares and (ii) certain shares subject to outstanding awards granted under the Company’s 2010 Equity Incentive Plan or 2011 Inducement Award Plan that may become available for issuance under the Amended 2020 Plan, as such shares become available from time to time.

Income taxes

Income taxes	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income taxes	Income taxes The income tax provision from income taxes in the periods presented is based upon the income (loss) before income taxes (in thousands): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Income tax (provision) benefit $ (456) $ 1,206 $ (1,279) $ (1,199) The Company’s income tax provision in the three and nine months ended September 30, 2021 was primarily related to income taxes on earnings from its foreign tax jurisdictions. The Company’s income tax benefit (provision) in the three and nine months ended September 30, 2020 was primarily related to updating the projected forecast of the tax provision from U.S. and non-U.S. operations. The Company projected a pretax loss for its U.S. operations and a higher effective tax rate based on non-U.S. operations for the three months ended September 30, 2020. The tax provision for the nine months ended September 30, 2020 was primarily related to income taxes on earnings from its foreign tax jurisdictions. 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 September 30, 2021, 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, 2020. On March 27, 2020, the U.S. enacted the Coronavirus Aid, Relief, and Economic Security (“CARES”) Act which provided certain tax relief measures. On December 27, 2020, the U.S. enacted the Consolidated Appropriations Act of 2021 (CAA) which extended and expanded certain tax relief measures created by the CARES Act. On March 11, 2021, the U.S. enacted the American Rescue Plan Act of 2021 (ARPA). These Acts have not had a material impact on the Company's operations to date and the Company will continue to evaluate the impact they may have, if any, on its future business.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent events	Subsequent Events Acquisition by Lumentum Corporation On November 4, 2021, NeoPhotonics announced an agreement (the “Lumentum Transaction”) through which Lumentum will acquire NeoPhotonics (the “Transaction”). Pursuant to the agreement, each issued and outstanding share of NeoPhotonics common stock will be converted into the right to receive $16.00 in cash at closing of the Transaction. In addition, Lumentum will make available to NeoPhotonics a working capital loan of $50 million. Lumentum is a designer and manufacturer of innovative optical and photonic products enabling optical networking and laser applications worldwide.

Basis of presentation and sig_2

Basis of presentation and significant accounting policies (Policies)	9 Months Ended
	Sep. 30, 2021
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 September 30, 2021 and for the three and nine months ended September 30, 2021 and 2020, 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. These condensed consolidated financial statements do not include all disclosures required by U.S. generally accepted accounting principles (“U.S. GAAP”) and should be read in conjunction with the Consolidated Financial Statements and Notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020. The results of operations for the three and nine months ended September 30, 2021 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 UncertaintiesThe 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 state of the global semiconductor market and supply chain; the successful and timely completion of product design efforts; the ability of the Company to sell its new products into new market segments; the general state of the U.S., China and world economies; the highly cyclical nature of the industries the Company serves; trade restrictions by the United States against the Company's customers in China, as well as potential retaliatory trade actions taken by China; the loss of any of its larger customers; restrictions on the Company's ability to sell to foreign customers due to additional U.S. or new China 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; 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, 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, future adverse developments with respect to the Covid-19 pandemic may have a negative impact on its sales, supply chain and results of operations. The inputs into the Company's judgments and estimates also consider the Department of Commerce Entities List restrictions on Huawei Technologies effective September 2020 for the Company and loss of business from Huawei Technologies.
Concentration	Concentration In the three months ended September 30, 2021, three customers were each greater than 10% of the Company’s total revenue, representing 60% of total revenue, and the Company's top five customers represented approximately 79% of the Company’s total revenue. In the three months ended September 30, 2020, three customers each were greater than 10% of revenue, representing 71% of total revenue, and our top five customers during this period represented 82% of total revenue. In the nine months ended September 30, 2021, four customers were each greater than 10% of the Company's total revenue, representing 67% of total revenue, and the Company's top five customers represented approximately 77% of the total revenue. In the nine months ended September 30, 2020, two customers each were greater than 10% of the Company's total revenue, representing 67% of total revenue, and the Company’s top five customers represented 82% of the Company’s total revenue. As of September 30, 2021, four customers accounted for a total of 65% of the Company’s total accounts receivable. As of December 31, 2020, three customers accounted for a total of 65% of the Company’s total accounts receivable.
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 and recoverability of long-lived assets; valuation allowances for deferred tax assets; valuation of excess and obsolete inventories; warranty reserves; and recognition of stock-based compensation, among others. Actual results could differ from these estimates.
Long-lived Assets	Long-lived Assets The Company assesses the impairment of long-lived assets whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. An impairment loss would be recognized when the sum of the future net cash flows expected to result from the use of the asset and its eventual disposition is less than its carrying amount. The estimated
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 December 2019, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (ASU 2019-12), which simplifies the accounting for income taxes. This guidance became effective for fiscal years beginning after December 15, 2020. The Company adopted this ASU in the first quarter of 2021 and the adoption of this standard did not have a material impact on the Company's consolidated financial statements. 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 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 optoelectronic laser, component and module 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 the 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 -

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2021
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 Nine Months Ended 2021 2020 2021 2020 High Speed Products $ 78,383 $ 94,532 $ 196,688 $ 277,245 Network Products and Solutions 5,359 7,866 12,989 25,725 Total revenue $ 83,742 $ 102,398 $ 209,677 $ 302,970 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 Nine Months Ended 2021 2020 2021 2020 China $ 26,026 $ 57,087 $ 66,209 $ 178,661 Americas 10,561 17,201 21,750 51,622 Rest of world 47,155 28,110 121,718 72,687 Total revenue $ 83,742 $ 102,398 $ 209,677 $ 302,970

Net income (loss) per share (Ta

Net income (loss) per share (Tables)	9 Months Ended
	Sep. 30, 2021
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 Nine Months Ended 2021 2020 2021 2020 Numerator: Net income (loss) $ (1,860) $ (4,903) $ (29,984) $ 7,129 Denominator: Weighted average shares used to compute per share amount: Basic 52,427 49,936 51,599 49,212 Diluted 52,427 49,936 51,599 51,411 Basic net income (loss) per share $ (0.04) $ (0.10) $ (0.58) $ 0.14 Diluted net income (loss) per share $ (0.04) $ (0.10) $ (0.58) $ 0.14
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 Nine Months Ended 2021 2020 2021 2020 Employee stock options 1,604 2,282 1,604 658 Restricted stock units 3,274 3,622 3,274 80 Market-based restricted stock units 134 612 134 612 Performance-based restricted stock units 240 90 240 90 Employee stock purchase plan 125 169 125 — 5,377 6,775 5,377 1,440

Cash, cash equivalents, short_2

Cash, cash equivalents, short-term investments, and restricted cash (Tables)	9 Months Ended
	Sep. 30, 2021
Cash and Cash Equivalents [Abstract]
Schedule of cash and cash equivalents	The following table summarizes the Company’s cash, cash equivalents and restricted cash (in thousands): September 30, 2021 December 31, 2020 Cash and cash equivalents $ 76,578 $ 95,117 Restricted cash 495 489 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 77,073 $ 95,606
Schedule of restricted cash	The following table summarizes the Company’s cash, cash equivalents and restricted cash (in thousands): September 30, 2021 December 31, 2020 Cash and cash equivalents $ 76,578 $ 95,117 Restricted cash 495 489 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 77,073 $ 95,606 September 30, 2021 December 31, 2020 Cash restricted in China as a result of unfulfilled government grants $ 458 $ 452 China earnings restricted to fund statutory common reserves in China 10,125 10,010 Loan agreements in Japan requiring local subsidiaries to maintain minimum net asset levels 895 969 Total restricted net assets in the Company's consolidated subsidiaries $ 11,478 $ 11,431
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 September 30, 2021 As of December 31, 2020 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 $ 27,674 $ — $ — $ 27,674 $ 27,669 $ — $ — $ 27,669 Reported as: Short-term investments $ 27,674 $ 27,669

Fair value disclosures (Tables)

Fair value disclosures (Tables)	9 Months Ended
	Sep. 30, 2021
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 September 30, 2021 As of December 31, 2020 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Short-term investments: Money market funds $ 27,674 $ — $ — $ 27,674 $ 27,669 $ — $ — $ 27,669 Other long-term assets: Mutual funds held in Rabbi Trust $ 847 $ — $ — $ 847 $ 810 $ — $ — $ 810

Balance sheet components (Table

Balance sheet components (Tables)	9 Months Ended
	Sep. 30, 2021
Balance Sheet Related Disclosures [Abstract]
Schedule of accounts receivable, net	Accounts receivable, net, consists of the following (in thousands): September 30, 2021 December 31, 2020 Accounts receivable $ 57,901 $ 45,277 Allowance for doubtful accounts — (45) $ 57,901 $ 45,232
Schedule of inventories, net	Inventories consist of the following (in thousands): September 30, 2021 December 31, 2020 Raw materials $ 27,699 $ 25,620 Work in process 14,105 9,196 Finished goods (1) 6,859 12,085 $ 48,663 $ 46,901 ________________________________________________________ (1) Finished goods inventory at customer vendor managed inventory locations was $1.8 million and $1.7 million as of September 30, 2021 and December 31, 2020, respectively.
Schedule of prepaid expenses and other current assets	Prepaid expenses and other current assets consist of the following (in thousands): September 30, 2021 December 31, 2020 Transition services agreement receivable (refer to Note 10) $ — $ 5,933 Prepaid taxes and taxes receivable 5,247 6,137 Receivables due from suppliers 10,009 4,891 Deposits and other prepaid expenses 2,869 2,417 Other receivable 548 795 $ 18,673 $ 20,173
Schedule of purchased intangible assets	Purchased intangible assets, net, consist of the following (in thousands): September 30, 2021 December 31, 2020 Gross Accumulated Net Gross Accumulated Net Technology and patents $ 37,777 $ (37,631) $ 146 $ 37,637 $ (37,021) $ 616 Customer relationships 15,476 (15,476) — 15,487 (15,487) — Leasehold interest 1,319 (480) 839 1,304 (452) 852 $ 54,572 $ (53,587) $ 985 $ 54,428 $ (52,960) $ 1,468
Schedule of estimated future amortization expense of purchased intangible assets	The estimated future amortization expense of purchased intangible assets as of September 30, 2021, was as follows (in thousands): 2021 (remaining three months) $ 149 2022 10 2023 10 2024 10 2025 10 Thereafter 796 $ 985
Schedule of accrued and other current liabilities	Accrued and other current liabilities consist of the following (in thousands): September 30, 2021 December 31, 2020 Employee-related $ 13,155 $ 19,656 Transition services agreement payables (refer to Note 10) 823 9,708 Operating lease liabilities, current 2,515 2,128 Income and other taxes payable 1,620 1,590 Accrued warranty 843 1,111 Other accrued expenses 6,027 7,860 $ 24,983 $ 42,053
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 Nine Months Ended 2021 2020 2021 2020 Beginning balance $ 903 $ 1,617 $ 1,111 $ 712 Warranty accruals 107 369 172 1,605 Settlements (167) (573) (440) (904) Ending balance $ 843 $ 1,413 $ 843 $ 1,413
Schedule of other noncurrent liabilities	Other noncurrent liabilities consist of the following (in thousands): September 30, 2021 December 31, 2020 Pension and other employee-related $ 3,490 $ 3,844 Asset retirement obligations 3,887 3,810 Transition services agreement payables (See Note 10) — 823 Deferred income tax liabilities 507 501 Government grant 431 606 $ 8,315 $ 9,584

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2021
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): September 30, 2021 December 31, 2020 Carrying Interest Carrying Interest Short-term borrowing: Note payable to Shanghai Pudong Development Bank $ 15,000 0.60 % $ — — % Unaccreted discount and issuance costs (178) — Short-term borrowing, net $ 14,822 $ — Long-term debt, current and noncurrent: Borrowing under Wells Fargo Credit Facility $ 20,241 1.90 % $ 21,030 2.01 % Mitsubishi Bank loans 5,633 1.07% -1.47% 7,662 1.05%-1.45% Mitsubishi Bank and Yamanashi Chuo Bank loan 3,805 1.07 % 5,002 1.07 % Finance lease liability 118 189 Total long-term debt 29,797 33,883 Unaccreted discount and issuance costs (212) (324) Total long-term debt, net of unaccreted discount and issuance costs $ 29,585 $ 33,559 Reported as: Current portion of long-term debt $ 3,015 $ 3,232 Long-term debt, net of current portion 26,570 30,327 Total long-term debt, net of unaccreted discount and issuance costs $ 29,585 $ 33,559
Schedule of maturities of notes payable and borrowings	As of September 30, 2021, maturities of notes payable and borrowings under line of credit are as follows (in thousands): 2021 (remaining three months) $ 853 2022 18,029 2023 3,011 2024 2,241 2025 422 Thereafter 20,241 $ 44,797

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Schedule of lease, cost	The components of lease expense were as follows (in thousands): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Operating lease cost $ 792 $ 757 $ 2,348 $ 2,273 Variable and short-term lease cost 774 574 2,074 1,472 Total lease cost $ 1,566 $ 1,331 $ 4,422 $ 3,745 Other information related to leases was as follows (in thousands, except lease term and discount rate): Nine Months Ended 2021 2020 Supplemental cash flow information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 2,493 $ 2,359 Weighted average remaining lease term Operating leases 5.7 years 6.7 years Weighted average discount rate Operating leases 6.3 % 6.5 %
Schedule of future minimum lease payments under non-cancellable leases	Future minimum lease payments under non-cancelable leases as of September 30, 2021 were as follows (in thousands): Operating Leases 2021 (remaining three months) $ 901 2022 3,465 2023 3,445 2024 3,345 2025 3,422 Thereafter 5,406 Total future minimum lease payments 19,984 Less imputed interest (3,319) Total $ 16,665
Schedule of operating leases	As of September 30, 2021 and December 31, 2020, the future minimum lease payments are captured in the Company's Consolidated Balance Sheets as follows: Operating Leases: September 30, 2021 December 31, 2020 Accrued and other current liabilities $ 2,515 $ 2,128 Operating lease liabilities, noncurrent 14,150 14,522 Total $ 16,665 $ 16,650

Stockholders' equity (Tables)

Stockholders' equity (Tables)	9 Months Ended
	Sep. 30, 2021
Stockholders' Equity Note [Abstract]
Schedule of accumulated other comprehensive loss	The components of accumulated other comprehensive income (loss), net of related taxes, were as follows (in thousands): Foreign Currency Translation Adjustments Defined Benefit Pension Plan Adjustment Total Accumulated Other Comprehensive Income (Loss) Balance as of December 31, 2020 $ 1,951 $ (216) $ 1,735 Other comprehensive loss, net of taxes of zero (555) — (555) Balances at September 30, 2021 $ 1,396 $ (216) $ 1,180

Restricted net assets (Tables)

Restricted net assets (Tables)	9 Months Ended
	Sep. 30, 2021
Restricted Net Assets [Abstract]
Schedule of restrictions on net assets	The following table summarizes the Company’s cash, cash equivalents and restricted cash (in thousands): September 30, 2021 December 31, 2020 Cash and cash equivalents $ 76,578 $ 95,117 Restricted cash 495 489 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 77,073 $ 95,606 September 30, 2021 December 31, 2020 Cash restricted in China as a result of unfulfilled government grants $ 458 $ 452 China earnings restricted to fund statutory common reserves in China 10,125 10,010 Loan agreements in Japan requiring local subsidiaries to maintain minimum net asset levels 895 969 Total restricted net assets in the Company's consolidated subsidiaries $ 11,478 $ 11,431

Stock-based compensation (Table

Stock-based compensation (Tables)	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Schedule of stock based compensation expense	The following table summarizes the stock-based compensation expense recognized in the three and nine months ended September 30, 2021 and 2020 (in thousands): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Cost of goods sold $ 403 $ 607 $ 1,523 $ 1,765 Research and development 565 748 2,171 2,505 Sales and marketing 353 565 1,168 1,833 General and administrative 873 853 2,949 2,975 $ 2,194 $ 2,773 $ 7,811 $ 9,078
Schedule of stock option and restricted stock unit activity	The following table summarizes the Company’s stock option and RSU activity, excluding market and performance-based RSUs, during the three and nine months ended September 30, 2021: Stock Options Restricted Stock Units Number of Number of Balance as of December 31, 2020 2,096,917 3,621,681 Granted 60,944 1,434,500 Exercised/Converted (529,482) (1,445,813) Cancelled/Forfeited (24,393) (336,294) Balances at September 30, 2021 1,603,986 3,274,074
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: Assumptions Weighted-average volatility 66% Risk-free interest rate 2.79% Expected dividends —%

Income taxes (Tables)

Income taxes (Tables)	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Schedule of income tax provisions	The income tax provision from income taxes in the periods presented is based upon the income (loss) before income taxes (in thousands): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Income tax (provision) benefit $ (456) $ 1,206 $ (1,279) $ (1,199)

Basis of presentation and sig_3

Basis of presentation and significant accounting policies (Details) - USD ($)	3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Concentration Risk [Line Items]
Asset impairment charges			$ 0
Customer concentration | Total revenue | Customer one
Concentration Risk [Line Items]
Percentage of concentration of credit risk	10.00%	10.00%		10.00%	10.00%
Customer concentration | Total revenue | Customer two
Concentration Risk [Line Items]
Percentage of concentration of credit risk	10.00%	10.00%		10.00%	10.00%
Customer concentration | Total revenue | Customer three
Concentration Risk [Line Items]
Percentage of concentration of credit risk	10.00%	10.00%		10.00%
Customer concentration | Total revenue | Customer four
Concentration Risk [Line Items]
Percentage of concentration of credit risk				10.00%
Customer concentration | Total revenue | Three customers
Concentration Risk [Line Items]
Percentage of concentration of credit risk	60.00%	71.00%
Customer concentration | Total revenue | Top five customers
Concentration Risk [Line Items]
Percentage of concentration of credit risk	79.00%	82.00%		77.00%	82.00%
Customer concentration | Total revenue | Four customers
Concentration Risk [Line Items]
Percentage of concentration of credit risk				67.00%
Customer concentration | Total revenue | Two customers
Concentration Risk [Line Items]
Percentage of concentration of credit risk					67.00%
Customer concentration | Accounts receivable | Three customers
Concentration Risk [Line Items]
Percentage of concentration of credit risk						65.00%
Customer concentration | Accounts receivable | Four customers
Concentration Risk [Line Items]
Percentage of concentration of credit risk				65.00%

Revenue - Revenue by Product Gr

Revenue - Revenue by Product Group (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenue	$ 83,742	$ 102,398	$ 209,677	$ 302,970
High Speed Products
Disaggregation of Revenue [Line Items]
Total revenue	78,383	94,532	196,688	277,245
Network Products and Solutions
Disaggregation of Revenue [Line Items]
Total revenue	$ 5,359	$ 7,866	$ 12,989	$ 25,725

Revenue - Revenue from External

Revenue - Revenue from External Customers by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenue	$ 83,742	$ 102,398	$ 209,677	$ 302,970
China
Disaggregation of Revenue [Line Items]
Total revenue	26,026	57,087	66,209	178,661
Americas
Disaggregation of Revenue [Line Items]
Total revenue	10,561	17,201	21,750	51,622
Rest of world
Disaggregation of Revenue [Line Items]
Total revenue	$ 47,155	$ 28,110	$ 121,718	$ 72,687

Revenue - Narrative (Details)

Revenue - Narrative (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Deferred revenue	$ 0	$ 0
Contract asset balance	$ 0	$ 0

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		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income (loss)	$ (1,860)	$ (4,903)	$ (29,984)	$ 7,129
Weighted average shares used to compute per share amount:
Basic (in shares)	52,427	49,936	51,599	49,212
Diluted (in shares)	52,427	49,936	51,599	51,411
Basic net income (loss) per share (in dollars per share)	$ (0.04)	$ (0.10)	$ (0.58)	$ 0.14
Diluted net income (loss) per share (in dollars per share)	$ (0.04)	$ (0.10)	$ (0.58)	$ 0.14

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		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Potentially dilutive securities, excluded from computation of diluted net income (loss) per share (in shares)	5,377	6,775	5,377	1,440
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)	1,604	2,282	1,604	658
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)	3,274	3,622	3,274	80
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)	134	612	134	612
Performance-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)	240	90	240	90
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)	125	169	125	0

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	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 76,578	$ 95,117
Restricted cash	495	489
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 77,073	$ 95,606	$ 95,274	$ 81,439

Cash, cash equivalents, short_4

Cash, cash equivalents, short-term investments and restricted cash - Summary of Unrealized Gains and Losses (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)investment	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)investment	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, realized gain (loss)	$ 0	$ 0	$ 0	$ 0
Debt securities, available-for-sale, impairment losses	$ 0	$ 0	$ 0	$ 0
Debt securities, unrealized loss position, 12 months or longer | investment	0		0
Short-term investments
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 27,674,000		$ 27,674,000		$ 27,669,000
Money market funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	27,674,000		27,674,000		27,669,000
Gross Unrealized Gains	0		0		0
Gross Unrealized Loss	0		0		0
Fair Value	$ 27,674,000		$ 27,674,000		$ 27,669,000

Fair value disclosures - Assets

Fair value disclosures - Assets Measured at Fair Value on Recurring Basis (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	$ 27,674,000	$ 27,669,000
Fair value, measurements, recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of liabilities	0
Fair value, measurements, recurring | Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	27,674,000	27,669,000
Fair value, measurements, recurring | Mutual funds held in Rabbi Trust
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	847,000	810,000
Fair value, measurements, recurring | Level 1 | Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	27,674,000	27,669,000
Fair value, measurements, recurring | Level 1 | Mutual funds held in Rabbi Trust
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	847,000	810,000
Fair value, measurements, recurring | Level 2 | Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair value, measurements, recurring | Level 2 | Mutual funds held in Rabbi Trust
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair value, measurements, recurring | Level 3 | Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair value, measurements, recurring | Level 3 | Mutual funds held in Rabbi Trust
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair value, measurements, nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of liabilities	0	0
Fair value of assets	$ 0	$ 0

Balance sheet components - Acco

Balance sheet components - Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Accounts receivable	$ 57,901	$ 45,277
Allowance for doubtful accounts	0	(45)
Account and trade note receivables, net	$ 57,901	$ 45,232

Balance sheet components - Inve

Balance sheet components - Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Raw materials	$ 27,699	$ 25,620
Work in process	14,105	9,196
Finished goods	6,859	12,085
Inventories	48,663	46,901
Finished goods, at vendor managed inventory locations	$ 1,800	$ 1,700

Balance sheet components - Prep

Balance sheet components - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Transition services agreement receivable	$ 0	$ 5,933
Prepaid taxes and taxes receivable	5,247	6,137
Receivables due from suppliers	10,009	4,891
Deposits and other prepaid expenses	2,869	2,417
Other receivable	548	795
Prepaid expenses and other current assets	$ 18,673	$ 20,173

Balance sheet components - Purc

Balance sheet components - Purchased Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross Assets	$ 54,572		$ 54,572		$ 54,428
Accumulated Amortization	(53,587)		(53,587)		(52,960)
Net Assets	985		985		1,468
Technology and patents
Finite-Lived Intangible Assets [Line Items]
Gross Assets	37,777		37,777		37,637
Accumulated Amortization	(37,631)		(37,631)		(37,021)
Net Assets	146		146		616
Amortization of Intangible Assets	200	$ 200	500	$ 600
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Assets	15,476		15,476		15,487
Accumulated Amortization	(15,476)		(15,476)		(15,487)
Net Assets	0		0		0
Leasehold interest
Finite-Lived Intangible Assets [Line Items]
Gross Assets	1,319		1,319		1,304
Accumulated Amortization	(480)		(480)		(452)
Net Assets	$ 839		$ 839		$ 852

Balance sheet components - Esti

Balance sheet components - Estimated Future Amortization Expense of Purchased Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
2021 (remaining three months)	$ 149
2022	10
2023	10
2024	10
2025	10
Thereafter	796
Net Assets	$ 985	$ 1,468

Balance sheet components - Accr

Balance sheet components - Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Employee-related	$ 13,155	$ 19,656
Transition services agreement payables	823	9,708
Operating lease liabilities, current	2,515	2,128
Income and other taxes payable	1,620	1,590
Accrued warranty	843	1,111
Other accrued expenses	6,027	7,860
Accrued and other current liabilities	$ 24,983	$ 42,053

Balance sheet components - Warr

Balance sheet components - Warranty Accrual (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward]
Beginning balance	$ 903	$ 1,617	$ 1,111	$ 712
Warranty accruals	107	369	172	1,605
Settlements	(167)	(573)	(440)	(904)
Ending balance	$ 843	$ 1,413	$ 843	$ 1,413

Balance sheet components - Othe

Balance sheet components - Other Noncurrent Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Pension and other employee-related	$ 3,490	$ 3,844
Asset retirement obligations	3,887	3,810
Transition services agreement payables	0	823
Deferred income tax liabilities	507	501
Government grant	431	606
Other noncurrent liabilities	$ 8,315	$ 9,584

Debt - Components of Debt Oblig

Debt - Components of Debt Obligations and Weighted Average Interest Rate (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Unaccreted discount and issuance costs	$ (212)	$ (324)
Short-term debt	14,822	0
Finance lease liability	118	189
Total long-term debt	29,797	33,883
Current portion of long-term debt	3,015	3,232
Long-term debt, net of current portion	26,570	30,327
Total long-term debt, net of unaccreted discount and issuance costs	29,585	33,559
Line of credit | Note payable to Shanghai Pudong Development Bank
Debt Instrument [Line Items]
Note payable to Shanghai Pudong Development Bank	15,000	0
Unaccreted discount and issuance costs	(178)	0
Short-term debt	$ 14,822	$ 0
Weighted average interest rate	0.60%	0.00%
Line of credit | Borrowing under Wells Fargo Credit Facility
Debt Instrument [Line Items]
Weighted average interest rate	1.90%	2.01%
Long-term debt, gross	$ 20,241	$ 21,030
Notes payable to banks | Mitsubishi Bank loans
Debt Instrument [Line Items]
Long-term debt, gross	$ 5,633	$ 7,662
Notes payable to banks | Mitsubishi Bank loans | Minimum
Debt Instrument [Line Items]
Weighted average interest rate	1.07%	1.05%
Notes payable to banks | Mitsubishi Bank loans | Maximum
Debt Instrument [Line Items]
Weighted average interest rate	1.47%	1.45%
Notes payable to banks | Mitsubishi Bank and Yamanashi Chuo Bank loan
Debt Instrument [Line Items]
Weighted average interest rate	1.07%	1.07%
Long-term debt, gross	$ 3,805	$ 5,002

Debt - Notes Payable and Short-

Debt - Notes Payable and Short-term Borrowing  (Details)	9 Months Ended
	Sep. 30, 2021USD ($)	Jun. 30, 2021CNY (¥)	Jun. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Notes payable | China | Minimum
Debt Instrument [Line Items]
Debt term	3 months
Notes payable | China | Maximum
Debt Instrument [Line Items]
Debt term	6 months
Notes payable | China | Subsidiaries | Credit Line Agreement | NeoPhotonics China
Debt Instrument [Line Items]
Credit facility, maximum borrowing amount		¥ 120,000,000	$ 18,600,000
Outstanding balance of line of credit facilities	$ 15,000,000			$ 0
Interest rate	3.00%
Loan fees	2.40%
Notes payable | China | Subsidiaries | Credit Line Agreement | NeoPhotonics Donggua
Debt Instrument [Line Items]
Credit facility, maximum borrowing amount		¥ 30,000,000	$ 4,600,000
Outstanding balance of line of credit facilities	$ 0
Bankers acceptance
Debt Instrument [Line Items]
Compensating balances	$ 0			$ 0

Debt - Credit Facilities (Detai

Debt - Credit Facilities (Details) - USD ($)	1 Months Ended	3 Months Ended
	Jun. 30, 2021	Sep. 30, 2021	May 31, 2021	Dec. 31, 2020
Borrowing under Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Accrued interest included in balance		$ 100,000
Line of credit | A&R Credit Agreement
Line of Credit Facility [Line Items]
Maximum revolver amount	$ 50,000,000
Outstanding balance of line of credit facilities			$ 21,000,000
Line of credit | Borrowing under Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Maximum revolver amount	$ 50,000,000
Outstanding balance of line of credit facilities		$ 20,200,000
Cash balance for borrowing	100.00%
Cash balance max borrowing (up to)	$ 15,000,000
Maximum revolver increase	$ 25,000,000
Commitment fee percent	0.25%
Maximum indebtedness under debt covenant	$ 20,000,000
Unused borrowing capacity	$ 5,000,000
Weighted average interest rate		1.90%		2.01%
Unused part of credit facility		$ 15,900,000
Minimum required unused borrowing capacity		$ 5,000,000
Line of credit | Borrowing under Wells Fargo Credit Facility | LIBOR
Line of Credit Facility [Line Items]
Weighted average interest rate		1.90%
Line of credit | Borrowing under Wells Fargo Credit Facility | Minimum
Line of Credit Facility [Line Items]
Revolver accounts receivable (up to)	90.00%
Line of credit | Borrowing under Wells Fargo Credit Facility | Minimum | LIBOR
Line of Credit Facility [Line Items]
TIBOR interest rate spread	1.50%
Line of credit | Borrowing under Wells Fargo Credit Facility | Minimum | Prime rate
Line of Credit Facility [Line Items]
TIBOR interest rate spread	0.50%
Line of credit | Borrowing under Wells Fargo Credit Facility | Maximum | LIBOR
Line of Credit Facility [Line Items]
TIBOR interest rate spread	1.75%
Line of credit | Borrowing under Wells Fargo Credit Facility | Maximum | Prime rate
Line of Credit Facility [Line Items]
TIBOR interest rate spread	0.75%

Debt - Mitsubishi Bank Loans (D

Debt - Mitsubishi Bank Loans (Details) - Mitsubishi Bank - Notes payable to banks $ in Millions	Feb. 25, 2015JPY (¥)	Feb. 25, 2015USD ($)	Jan. 31, 2018JPY (¥)	Jan. 31, 2018USD ($)	Mar. 31, 2017JPY (¥)	Sep. 30, 2021JPY (¥)	Sep. 30, 2021USD ($)	Mar. 31, 2017USD ($)	Feb. 25, 2015USD ($)
Mitsubishi Bank loans
Debt Instrument [Line Items]
Debt issuance costs	¥ 40,500,000								$ 0.4
Mitsubishi Bank loans | TIBOR
Debt Instrument [Line Items]
LIBOR rate	1.40%	1.40%
Mitsubishi Bank Term Loan A
Debt Instrument [Line Items]
Debt, aggregate principal amount	¥ 500,000,000								4.4
Repayments of lines of credit			¥ 500,000,000	$ 4.4
Mitsubishi Bank Term Loan B
Debt Instrument [Line Items]
Debt, aggregate principal amount	1,000,000,000								$ 9
Debt, periodic principal payments	8,300,000	$ 0.1
Debt, lump sum payment on the maturity date	¥ 8,400,000	$ 0.1
Mitsubishi Bank Term Loan B | TIBOR
Debt Instrument [Line Items]
LIBOR rate	1.40%	1.40%
2015 Mitsubishi Bank Loan
Debt Instrument [Line Items]
Long-term debt						¥ 341,700,000	$ 3.1
2017 Mitsubishi Bank Loan
Debt Instrument [Line Items]
Debt, aggregate principal amount					¥ 690,000,000			$ 6.2
Long-term debt						¥ 287,500,000	$ 2.6
Debt term					72 months
Line of credit facility, outstanding					¥ 690,000,000			$ 6.2
2017 Mitsubishi Bank Loan | TIBOR
Debt Instrument [Line Items]
LIBOR rate					1.00%

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 ($)	Sep. 30, 2021USD ($)	Sep. 30, 2021JPY (¥)	Jan. 31, 2018JPY (¥)
Debt Instrument [Line Items]
Credit facility, maximum borrowing amount	$ 7.6			¥ 850,000,000
Debt term	82 months
Long-term debt		$ 3.8	¥ 425,000,000
TIBOR
Debt Instrument [Line Items]
TIBOR interest rate spread	1.00%

Debt - Schedule of Maturities o

Debt - Schedule of Maturities of Notes Payable and Borrowings (Details) $ in Thousands	Sep. 30, 2021USD ($)
Debt Disclosure [Abstract]
2021 (remaining three months)	$ 853
2022	18,029
2023	3,011
2024	2,241
2025	422
Thereafter	20,241
Total long-term debt, current and non-current	$ 44,797

Leases - Narrative (Details)

Leases - Narrative (Details)	9 Months Ended
	Sep. 30, 2021
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		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating lease cost	$ 792	$ 757	$ 2,348	$ 2,273
Variable and short-term lease cost	774	574	2,074	1,472
Total lease cost	$ 1,566	$ 1,331	$ 4,422	$ 3,745

Leases - Cash Flows (Details)

Leases - Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Cash paid for amounts included in the measurement of lease liabilities: operating cash flows from operating leases	$ 2,493	$ 2,359
Weighted average remaining lease term, operating leases	5 years 8 months 12 days	6 years 8 months 12 days
Weighted average discount rate, operating leases	6.30%	6.50%

Leases - Leases, Liability, Mat

Leases - Leases, Liability, Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Operating Leases
2021 (remaining three months)	$ 901
2022	3,465
2023	3,445
2024	3,345
2025	3,422
Thereafter	5,406
Total future minimum lease payments	19,984
Less imputed interest	(3,319)
Total	$ 16,665	$ 16,650

Leases - Balance Sheet Informat

Leases - Balance Sheet Information (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Operating Leases, Accrued and other current liabilities	$ 2,515	$ 2,128
Operating Leases, Operating lease liabilities, noncurrent	14,150	14,522
Total	$ 16,665	$ 16,650
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued and other current liabilities	Accrued and other current liabilities

Japan pension plan (Details)

Japan pension plan (Details) - Japan - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Pension liability	$ 2.9	$ 3.7
Pension liability included in accrued and other current liabilities	$ 0.3	$ 0.7

Commitments and contingencies (

Commitments and contingencies (Details) - APAT OE arbitration	Oct. 27, 2020CNY (¥)	Oct. 27, 2020USD ($)	Sep. 30, 2021USD ($)
APAT OE
Commitments And Contingencies Disclosure [Line Items]
Paid by other party	¥ 58,136,669	$ 8,500,000
Gain on litigation settlement		(3,000,000)
Payable due to litigation settlement			$ 800,000
Receivable due from litigation settlement			$ 0
APAT OE | NeoChina
Commitments And Contingencies Disclosure [Line Items]
Paid by other party	52,014,519	7,600,000
Interest receivable	6,122,150	900,000
Gain on litigation settlement	¥ 58,136,669	8,500,000
APAT HK
Commitments And Contingencies Disclosure [Line Items]
Gain on litigation settlement		(10,531,515)
Loss contingency, damages awarded, value		10,031,515
Interest payment		$ 500,000

Stockholders' equity - Narrativ

Stockholders' equity - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Sep. 30, 2021
Class of Stock [Line Items]
Accumulated deficit subject to restriction	$ 10
China | Subsidiaries
Class of Stock [Line Items]
Accumulated profits (at least)	10.00%
Stock options
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)		6,694,262
ESPP
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)		1,156,415

Stockholders' equity - Schedule

Stockholders' equity - Schedule of Accumulated Other Comprehensive Loss (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 157,392,000	$ 179,028,000	$ 180,407,000	$ 160,206,000
Other comprehensive loss, net of taxes of zero	(243,000)	5,317,000	(555,000)	3,808,000
Ending balance	157,141,000	181,518,000	157,141,000	181,518,000
Other comprehensive loss, tax			0
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			1,951,000
Other comprehensive loss, net of taxes of zero			(555,000)
Ending balance	1,396,000		1,396,000
Defined Benefit Pension Plan Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(216,000)
Other comprehensive loss, net of taxes of zero			0
Ending balance	(216,000)		(216,000)
Accumulated other comprehensive income (loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	1,423,000	(9,380,000)	1,735,000	(7,871,000)
Ending balance	$ 1,180,000	$ (4,063,000)	$ 1,180,000	$ (4,063,000)

Restricted net assets (Details)

Restricted net assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted net assets in the Company's consolidated subsidiaries	$ 11,478		$ 11,431
Stockholders' equity	157,141	$ 157,392	180,407	$ 181,518	$ 179,028	$ 160,206
Cash restricted in China as a result of unfulfilled government grants
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted net assets in the Company's consolidated subsidiaries	458		452
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	10,125		10,010
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	$ 895		$ 969

Stock-based compensation - Summ

Stock-based compensation - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	$ 2,194	$ 2,773	$ 7,811	$ 9,078
Cost of goods sold
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	403	607	1,523	1,765
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	565	748	2,171	2,505
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	353	565	1,168	1,833
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	$ 873	$ 853	$ 2,949	$ 2,975

Stock-based compensation - Narr

Stock-based compensation - Narrative (Details) - USD ($)	Jun. 01, 2021	Jul. 31, 2021	Apr. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Amended 2020 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)	900,000
Shares available under the 2020 plan (in shares)	2,821,414
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense				$ 300,000		$ 300,000
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense				$ 19,400,000		$ 19,400,000
Shares vested (in shares)						1,445,813
Shares canceled/forfeited (in shares)						336,294
Awards granted in the period (in shares)						1,434,500
Shares outstanding (in shares)				3,274,074		3,274,074		3,621,681
Market-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate grants awarded (in shares)				705,000		705,000
Shares outstanding (in shares)				133,875		133,875
Weighted average closing price vesting trigger				30 days		30 days
Shares vested (in shares)						437,125
Shares canceled/forfeited (in shares)						134,000
Unrecognized share based compensation				$ 200,000		$ 200,000
Performance-based RSUs | April 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested (in shares)						0
Shares canceled/forfeited (in shares)						14,950
Awards granted in the period (in shares)			90,400
Revenue over four fiscal quarters (at least)			$ 425,000,000
Performance-based RSUs | July 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested (in shares)						0
Awards granted in the period (in shares)		165,000
Revenue over four fiscal quarters (at least)		$ 100,000,000
SAUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted in the period (in shares)				0	0	0	0
Shares outstanding (in shares)				150,000		150,000		150,000
SAU-related liabilities				$ 600,000		$ 600,000		$ 700,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense				$ 100,000		100,000
Inventories
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation capitalized						$ 200,000		$ 300,000

Stock-based compensation - Stoc

Stock-based compensation - Stock Options and RSUs (Details)	9 Months Ended
	Sep. 30, 2021shares
Stock Options
Number of Shares
Beginning Balance (in shares)	2,096,917
Granted (in shares)	60,944
Exercised/Converted (in shares)	(529,482)
Cancelled/Forfeited (in shares)	(24,393)
Ending Balance (in shares)	1,603,986
Restricted Stock Units
Number of Units
Beginning Balance (in shares)	3,621,681
Granted (in shares)	1,434,500
Exercised/Converted (in shares)	(1,445,813)
Cancelled/Forfeited (in shares)	(336,294)
Ending Balance (in shares)	3,274,074

Stock-based compensation - Valu

Stock-based compensation - Valuation Assumptions of Stock-based Awards (Details) - Market-based RSUs	9 Months Ended
	Sep. 30, 2021
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%

Income taxes - Provision for In

Income taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income tax (provision) benefit	$ (456)	$ 1,206	$ (1,279)	$ (1,199)

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent event - Lumentum Transaction $ / shares in Units, $ in Millions	Nov. 04, 2021USD ($)$ / shares
Lumentum | Available
Subsequent Event [Line Items]
Working capital loan | $	$ 50
Lumentum
Subsequent Event [Line Items]
Cash paid at closing (in dollars per share) | $ / shares	$ 16