| Document and Entity Information | Jan. 24, 2022 |
| Cover [Abstract] | |
| Entity Registrant Name | NEOPHOTONICS CORP |
| Amendment Flag | false |
| Entity Central Index Key | 0001227025 |
| Document Type | 8-K |
| Document Period End Date | Jan. 24, 2022 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-35061 |
| Entity Tax Identification Number | 94-3253730 |
| Entity Address, Address Line One | NeoPhotonics Corporation |
| Entity Address, Address Line Two | 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 |
| Written Communications | false |
| Soliciting Material | true |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.0025 per share |
| Trading Symbol | NPTN |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
