The Company and basis of presentation	12 Months Ended
Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company and basis of presentation	The Company and basis of presentation Business and organization NeoPhotonics Corporation and its subsidiaries (NeoPhotonics or the Company) develops, manufactures and sells optoelectronic products that transmit, receive and switch high speed digital optical signals for communications networks. The Company sells its products worldwide, primarily to leading network equipment manufacturers. 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; failure to successfully integrate completed acquisitions; 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. Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. Intercompany accounts and transactions have been eliminated in consolidation. Going Concern Accounting Standards Update (“ASU”) No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern, requires an entity to disclose information about its potential inability to continue as a going concern when conditions and events indicate that it is probable that the entity may be unable to meet its obligations as they become due within one year. Management has assessed the Company’s ability to continue as a going concern within one year of the filing date of this Annual Report on Form 10-K with the Securities and Exchange Commission ("SEC") in March 2019. The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and satisfaction of liabilities in the normal course of business. As of December 31, 2018, the Company’s working capital was $116.8 million, including available cash, cash equivalents, short-term investments and restricted cash of approximately $76.7 million. In 2018, the Company had operating losses of $41.7 million and cash from operations of $19.6 million. It had an accumulated deficit of approximately $397.5 million as of December 31, 2018. Through 2017 and the early part of 2018, the Company's operating results and cash flows were negatively affected by demand that was lower than customer estimates that were used to put capacity in place in 2016 and 2017. In the second half of 2018, demand continued to strengthen, primarily due to volume growth in the Americas as a result of metro and, particularly, data center interconnect deployments, as well as being the result of increased domestic provincial deployments in China plus exports by Chinese OEMs for international deployments. To adjust to the demand that was less than estimates used for capacity decisions, the Company implemented restructuring plans in May and September 2017 that included a reduction in force and consolidation of facilities, in order to reduce expenses. The Company has also reduced or delayed certain product development projects and capital expenditures, aggressively pursued collections of accounts and notes receivable and continued to closely manage production and inventory levels. The Company continues to implement actions to improve cash flow and profitability. In September 2017, the Company entered into a revolving line of credit agreement with Wells Fargo Bank, National Association ("Wells Fargo") which provides for borrowings under an accounts receivable based formula up to a maximum of $50.0 million. As of December 31, 2018, $36.0 million was outstanding under this line. The remaining borrowing capacity as of December 31, 2018 was $14.0 million, of which $5.0 million is required to be maintained as unused borrowing capacity. Borrowings under the Wells Fargo line are not due until June 30, 2022 as long as the borrowing base is not less than the outstanding amount (see Note 12). Additionally, the Company had $4.8 million of notes payable and $2.9 million of current portion of long-term debt as of December 31, 2018, which it plans to pay out of its existing available cash. The Company currently believes it will have sufficient resources to fund its currently planned operations and expenditures over the next twelve months without additional financing or other actions. In addition, the Company believes there are a number of ongoing and potential actions that may further strengthen its projected cash and projected financial position. The Company operates in an industry that makes its prospects difficult to evaluate with certainty. Future declines in China market demand or other changes to the Company’s forecasts could adversely affect the Company’s results of operations, financial position and cash flows. As a result, the Company may need to raise additional debt or equity capital to fund its operations. Any additional debt arrangements may likely require regular interest and principal payments which could adversely affect the Company’s operations. There can be no assurance that additional debt or equity capital will be available on acceptable terms, or at all.

The Company and basis of presentation

Business and organization

NeoPhotonics Corporation and its subsidiaries (NeoPhotonics or the Company) develops, manufactures and sells optoelectronic products that transmit, receive and switch high speed digital optical signals for communications networks. The Company sells its products worldwide, primarily to leading network equipment manufacturers.

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; failure to successfully integrate completed acquisitions; 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.

Consolidation

The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. Intercompany accounts and transactions have been eliminated in consolidation.

Going Concern

Accounting Standards Update (“ASU”) No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern, requires an entity to disclose information about its potential inability to continue as a going concern when conditions and events indicate that it is probable that the entity may be unable to meet its obligations as they become due within one year. Management has assessed the Company’s ability to continue as a going concern within one year of the filing date of this Annual Report on Form 10-K with the Securities and Exchange Commission ("SEC") in March 2019. The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and satisfaction of liabilities in the normal course of business.

As of December 31, 2018, the Company’s working capital was $116.8 million, including available cash, cash equivalents, short-term investments and restricted cash of approximately $76.7 million. In 2018, the Company had operating losses of $41.7 million and cash from operations of $19.6 million. It had an accumulated deficit of approximately $397.5 million as of December 31, 2018.

Through 2017 and the early part of 2018, the Company's operating results and cash flows were negatively affected by demand that was lower than customer estimates that were used to put capacity in place in 2016 and 2017. In the second half of 2018, demand continued to strengthen, primarily due to volume growth in the Americas as a result of metro and, particularly, data center interconnect deployments, as well as being the result of increased domestic provincial deployments in China plus exports by Chinese OEMs for international deployments.

To adjust to the demand that was less than estimates used for capacity decisions, the Company implemented restructuring plans in May and September 2017 that included a reduction in force and consolidation of facilities, in order to reduce expenses. The Company has also reduced or delayed certain product development projects and capital expenditures, aggressively pursued collections of accounts and notes receivable and continued to closely manage production and inventory levels. The Company continues to implement actions to improve cash flow and profitability.

In September 2017, the Company entered into a revolving line of credit agreement with Wells Fargo Bank, National Association ("Wells Fargo") which provides for borrowings under an accounts receivable based formula up to a maximum of $50.0 million. As of December 31, 2018, $36.0 million was outstanding under this line. The remaining borrowing capacity as of December 31, 2018 was $14.0 million, of which $5.0 million is required to be maintained as unused borrowing capacity. Borrowings under the Wells Fargo line are not due until June 30, 2022 as long as the borrowing base is not less than the outstanding amount (see Note 12). Additionally, the Company had $4.8 million of notes payable and $2.9 million of current portion of long-term debt as of December 31, 2018, which it plans to pay out of its existing available cash.

The Company currently believes it will have sufficient resources to fund its currently planned operations and expenditures over the next twelve months without additional financing or other actions. In addition, the Company believes there are a number of ongoing and potential actions that may further strengthen its projected cash and projected financial position.

The Company operates in an industry that makes its prospects difficult to evaluate with certainty. Future declines in China market demand or other changes to the Company’s forecasts could adversely affect the Company’s results of operations, financial position and cash flows. As a result, the Company may need to raise additional debt or equity capital to fund its operations. Any additional debt arrangements may likely require regular interest and principal payments which could adversely affect the Company’s operations. There can be no assurance that additional debt or equity capital will be available on acceptable terms, or at all.