Number Of Debt Instruments

No definition available.

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Namespace Prefix:	nptn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of compensating balance requirement for bank acceptance drafts.

+ References

No definition available.

+ Details

Name:	nptn_PercentageOfCompensatingBalanceRequirementForBankAcceptanceDrafts
Namespace Prefix:	nptn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of a specific compensating balance arrangement that is maintained under an agreement for a bank loan or future credit availability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_CompensatingBalanceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value of the amount outstanding under the credit facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611

+ Details

Name:	us-gaap_LineOfCreditFacilityFairValueOfAmountOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Balance Type:
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- Details

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- Details

Name:	srt_StatementGeographicalAxis=country_CN
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Balance Type:
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- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_NotesPayableOtherPayablesMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_FirstCreditFacilityExpiresNovember2021Member
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_SecondLineOfCreditExpiresNovember2021Member
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
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- Details

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Debt - Notes Payable and Short-term Borrowing (Details)	3 Months Ended
Debt - Notes Payable and Short-term Borrowing (Details)	Mar. 31, 2021 CNY (¥) line_of_credit	Mar. 31, 2021 USD ($) line_of_credit	Dec. 31, 2020 USD ($)
Bankers acceptance
Debt Instrument [Line Items]
Restricted cash and investments, current		$ 0	$ 0
Bankers acceptance \| Subsidiaries
Debt Instrument [Line Items]
Outstanding balance of line of credit facilities		$ 0	$ 0
China \| Notes payable
Debt Instrument [Line Items]
Number of debt instruments \| line_of_credit	2	2
China \| Notes payable \| First line of credit facility, expires November 2021
Debt Instrument [Line Items]
Credit facility, maximum borrowing amount	¥ 120,000,000.0	$ 18,300,000
China \| Notes payable \| Second line of credit facility, expires November 2021 \| Subsidiaries
Debt Instrument [Line Items]
Credit facility, maximum borrowing amount	¥ 30,000,000.0	4,600,000
China \| Notes payable \| Minimum
Debt Instrument [Line Items]
Debt instrument, term	3 months
China \| Notes payable \| Maximum
Debt Instrument [Line Items]
Debt instrument, term	6 months
China \| Bankers acceptance \| First line of credit facility, expires November 2021
Debt Instrument [Line Items]
Credit facility, maximum borrowing amount	¥ 240,000,000.0	36,600,000
Percentage of compensating balance requirement for bank acceptance drafts (up to)	50.00%
China \| Bankers acceptance \| Second line of credit facility, expires November 2021 \| Subsidiaries
Debt Instrument [Line Items]
Credit facility, maximum borrowing amount	¥ 60,000,000.0	$ 9,200,000
Percentage of compensating balance requirement for bank acceptance drafts (up to)	50.00%