Basis of presentation and significant accounting policies (Policies)	3 Months Ended
	Mar. 31, 2017
Basis of presentation and significant accounting policies
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The condensed consolidated financial statements of NeoPhotonics Corporation (“NeoPhotonics” or the “Company”) as of March 31, 2017 and for the three months ended March 31, 2017 and 2016, have been prepared in accordance with the instructions on Form 10-Q pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). In accordance with those rules and regulations, the Company has omitted certain information and notes normally provided in the Company’s annual consolidated financial statements. In the opinion of management, the condensed consolidated financial statements contain all adjustments, consisting only of normal recurring items, except as otherwise noted, necessary for the fair presentation of the Company’s financial position and results of operations for the interim periods. The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by U.S. generally accepted accounting principles (“U.S. GAAP”). These condensed consolidated financial statements should be read in conjunction with the Consolidated Financial Statements and Notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2016. The results of operations for the three months ended March 31, 2017 are not necessarily indicative of the results expected for the entire fiscal year. All intercompany accounts and transactions have been eliminated. Certain Significant Risks and Uncertainties The Company operates in a dynamic industry and, accordingly, can be affected by a variety of factors. For example, any of the following areas could have a negative effect on the Company in terms of its future financial position, results of operations or cash flows: the general state of the U.S., China and world economies; the highly cyclical nature of the industries the Company serves; the loss of any of a small number of its larger customers; ability to obtain additional financing; inability to meet certain debt covenants; fundamental changes in the technology underlying the Company’s products; the hiring, training and retention of key employees; successful and timely completion of product design efforts; and new product design introductions by competitors.
Use of estimates	Use of Estimates The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported revenue and expenses during the reporting period. Significant estimates made by management include: the useful lives of property, plant and equipment and intangible assets as well as future cash flows to be generated by those assets; fair values of identifiable assets acquired and liabilities assumed in business combinations; allowances for doubtful accounts; valuation allowances for deferred tax assets; valuation of excess and obsolete inventories; warranty reserves; litigation accrual and recognition of stock-based compensation, among others. Actual results could differ from these estimates.
Concentration	Concentration In the three months ended March 31, 2017, Huawei Technologies Co. Ltd. and their affiliate HiSilicon Technologies (together with Huawei Technologies Co. Ltd., “Huawei”) and Ciena Corporation (“Ciena”) accounted for approximately 41% and 14% of the Company’s total revenue, respectively, and the Company’s top ten customers represented approximately 90% of the Company’s total revenue. In the three months ended March 31, 2016, Huawei and Ciena accounted for approximately 54% and 16% of the Company’s total revenue, respectively, and the Company’s top ten customers represented approximately 92% of the Company’s total revenue. As of March 31, 2017, one customer accounted for approximately 48% of the Company’s accounts receivable. As of December 31, 2016, three customers accounted for approximately 42%, 12% and 12%, respectively, of the Company’s accounts receivable.
Stock-based compensation	Effective January 1, 2017, the Company adopted ASU 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”). ASU 2016-09 simplifies certain aspects of the accounting for shared-based payment transactions, including income taxes, classification of awards and classification on the statement of cash flows. It eliminates that requirement to delay the recognition of excess tax benefits until they reduce current taxes payable. Under this standard, previously unrecognized excess tax benefits shall be recognized on a modified retrospective basis. Upon adoption, the Company’s previously unrecognized excess tax benefits of $8.6 million had no impact on its accumulated deficit balance as the related U.S. deferred tax assets were fully offset by a valuation allowance. The Company elected to apply the change in presentation on the statements of cash flows prospectively and elected to continue to account for estimated forfeitures over the vest period of the shared-based awards.
Inventories	Effective January 1, 2017, the Company also adopted ASU 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory (“ASU 2015-11”). ASU 2015-11 requires entities to measure most inventory “at the lower of cost and net realizable value” but does not apply to inventories that are measured by using either the last-in, first-out method or the retail inventory method. The impact on the Company’s consolidated financial statements upon the adoption of this standard was immaterial.
Recent accounting pronouncements	Recent accounting pronouncements In January 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment (“ASU 2017-04”). This standard amends the goodwill impairment test to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, up to the total amount of goodwill allocated to that reporting unit. ASU 2017-04 is effective prospectively for interim and annual periods beginning after December 15, 2019. Early adoption is permitted. The Company is in the process of evaluating the impact of adoption on its consolidated financial statements. In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business (“ASU 2017-01”). This standard provides a framework in determining when a set of assets and activities is a business. ASU 2017-01 is effective for interim and annual periods beginning after December 15, 2017 on a prospective basis. The impact on the Company’s financial statements upon the adoption of this standard is expected to be immaterial. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (“ASC 2016-18”). This standard provides guidance on the classification and presentation of restricted cash in the statement of cash flows and must be applied retrospectively. ASU 2016-18 is effective for fiscal years beginning after December 15, 2017. Early adoption is permitted. The Company is in the process of evaluating the impact of adoption on its consolidated financial statements. In October 2016, the FASB issued ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory (“ASU 2016-16”). This standard provides guidance on the tax accounting for the transferring and receiving entities upon transfer of an asset. ASU 2016-16 is effective for the Company’s interim and annual periods beginning after December 15, 2017 and should be applied on a modified retrospective basis. Early adoption is permitted. The Company is in the process of evaluating the impact of adoption on its consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”). This standard provides guidance on the classification of certain cash receipts and payments in the statement of cash flows. It is effective, retrospectively, for the Company’s annual and interim reporting periods beginning after December 15, 2017 or prospectively from the earliest data practicable if retrospective application is impracticable. Early adoption is permitted. The Company is in the process of evaluating the impact of adoption on its consolidated financial statements. 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. It is effective for the Company’s annual and interim reporting periods beginning after December 15, 2019. Early adoption is permitted. The Company is in the process of evaluating the impact of adoption on its consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (“ASU 2016-02”). ASU 2016-02 introduces a lessee model that requires recognition of assets and liabilities arising from qualified leases on the consolidated balance sheets and consolidated statements of operations and to disclose qualitative and quantitative information about lease transactions. It is effective for interim and annual periods beginning after December 15, 2018. Early adoption is permitted. A modified retrospective transition is required with certain optional practical expedients allowed. The Company is in the process of evaluating the impact of adoption on its consolidated financial statements. In January 2016, the FASB issued ASU 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities (“ASU 2016-01”). ASU 2016-01 revises an entity’s accounting related to (1) the classification and measurement of investments in equity securities and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. It also amends certain disclosure requirements associated with the fair value of financial instruments and is effective for the Company’s annual and interim reporting periods beginning after December 15, 2017. Early adoption is permitted. The Company is in the process of evaluating the impact of adoption on its consolidated financial statements. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). The standard, along with the amendments issued in 2016 and 2015, provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. The core principle of the model is to recognize revenue when control of the goods or services transfers to the customer, as opposed to recognizing revenue when the risks and rewards transfer to the customer under the existing revenue guidance. This standard, as amended, is effective for annual and interim periods beginning after December 15, 2017 and permits entities to early adopt for annual and interim reporting periods beginning after December 15, 2016. Companies are permitted to either apply the requirements retrospectively to all prior periods presented, or apply the requirements in the year of adoption, through a cumulative adjustment. The Company expects to adopt this standard, as amended, effective January 1, 2018 and is in the process of evaluating the impact of adoption on its consolidated financial statements.