Name:	nptn_DebtCovenantLiquidityRequirementsUnderLineOfCreditFacility
Namespace Prefix:	nptn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt, lump sum payment on the maturity date.

+ References

No definition available.

+ Details

Name:	nptn_DebtLumpSumPaymentOnMaturityDate
Namespace Prefix:	nptn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The maximum amount of indebtedness under the debt covenant.

+ References

No definition available.

+ Details

Name:	nptn_LineOfCreditFacilityMaximumIndebtednessUnderDebtCovenant
Namespace Prefix:	nptn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit Facility, Minimum Required Unused Borrowing Capacity

+ References

No definition available.

+ Details

Name:	nptn_LineofCreditFacilityMinimumRequiredUnusedBorrowingCapacity
Namespace Prefix:	nptn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the number of credit facilities available under an arrangement.

+ References

No definition available.

+ Details

Name:	nptn_NumberOfCreditFacilities
Namespace Prefix:	nptn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- 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

Revolver Accounts Receivable

+ References

No definition available.

+ Details

Name:	nptn_RevolverAccountsReceivable
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

+ Details

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

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

Increase for accrued, but unpaid interest on the debt instrument for the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_DebtInstrumentIncreaseAccruedInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

+ References

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPaymentPrincipal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

+ Details

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

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

+ Details

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

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ 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(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

+ Details

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

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

+ Details

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

- 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=118260190&loc=d3e13433-108611

+ Details

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

- Definition

Amount of increase (decrease) of the credit facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityIncreaseDecreaseForPeriodNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

+ Details

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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

- Definition

The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: 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))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: 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(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_ProceedsFromLinesOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_RepaymentsOfLinesOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow for a borrowing supported by a written promise to pay an obligation.

+ References

+ Details

Name:	us-gaap_RepaymentsOfNotesPayable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

+ Details

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

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=nptn_ComericaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=nptn_MitsubishiBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_SeniorSecuredRevolvingCreditFacilityExpiresAprilTwoThousandSeventeenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_FederalFundsEffectiveSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=nptn_DailyAdjustingLondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_WellsFargoCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_PrimeRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_TermLoanAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=nptn_TokyoInterbankOfferRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_TermLoanBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_MitsubishiBankTermLoanAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_NotesPayableToBanksMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_MitsubishiBankLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_MitsubishiBankLoan2017Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_TermLoanCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=nptn_MitsubishiBankandTheTamanashiChouBanLtd.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_SecondLineOfCreditExpiresJuly2019Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_SubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_BankersAcceptanceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_AmendedComericaBankCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_NotesPayableToBanksMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_NotesPayableCITICBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=country_CN
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=nptn_CITICBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=nptn_BankAcceptanceDraftsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nptn_FirstCreditFacilityExpiresJuneTwoThousandSixteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=us-gaap_NonUsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt - Narrative (Details)		1 Months Ended									12 Months Ended
Debt - Narrative (Details)	Feb. 25, 2015 JPY (¥)	Aug. 31, 2018 USD ($)	Feb. 28, 2018 USD ($)	Jan. 31, 2018 USD ($)	Jan. 31, 2018 JPY (¥)	Dec. 31, 2017 USD ($)	Nov. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jul. 31, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2019 USD ($) debt_instrument	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2019 JPY (¥)	Dec. 31, 2019 CNY (¥)	Jun. 14, 2019 USD ($)	Jan. 31, 2018 JPY (¥)	Dec. 31, 2017 CNY (¥)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 JPY (¥)	Feb. 25, 2015 USD ($)	Feb. 25, 2015 JPY (¥)
Debt Instrument [Line Items]
Repayment of notes payable											$ 4,774,000	$ 3,732,000	$ 11,639,000
Long-term debt											42,281,000	$ 53,351,000
Accrued interest rolled into principal amount											1,400,000
Comerica \| Revolving Credit Facility
Debt Instrument [Line Items]
Current borrowing capacity						$ 30,000,000.0							30,000,000.0
Mitsubishi Bank
Debt Instrument [Line Items]
Short-term line of credit facility \| ¥														¥ 516,700,000
Senior Secured Revolving Credit Facility, expires April 2017 \| Credit Facility Base Rate \| Comerica
Debt Instrument [Line Items]
Debt instrument, basis spread								1.75%
Senior Secured Revolving Credit Facility, expires April 2017 \| Libor Plus Rate \| Comerica
Debt Instrument [Line Items]
Debt instrument, basis spread								2.75%
Senior Secured Revolving Credit Facility, expires April 2017 \| Federal Funds Effective Rate \| Comerica
Debt Instrument [Line Items]
Debt instrument, basis spread								1.00%
Senior Secured Revolving Credit Facility, expires April 2017 \| Daily Adjusting LIBOR Rate \| Comerica
Debt Instrument [Line Items]
Debt instrument, basis spread								1.00%
Wells Fargo Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Line of credit maximum borrowing capacity								$ 50,000,000.0
Short-term line of credit facility								30,000,000.0
Repayments of lines of credit											10,000,000.0
Outstanding balance of line of credit facilities											$ 27,300,000
Line of credit facility, maximum indebtedness under debt covenant								$ 20,000,000.0
Cash balance available for borrowing								100.00%
Cash balance max borrowing								$ 15,000,000.0
Line of credit facility, increase (decrease)								25,000,000.0
Repayment of notes payable								20,000,000.0
Unused borrowing capacity								$ 5,000,000.0								$ 5,000,000.0
Interest rate											3.72%	4.41%		3.72%	3.72%
Line of credit remaining borrowing capacity											$ 10,400,000
Required amount to be maintained as unused borrowing capacity											5,000,000.0
Wells Fargo Credit Facility \| Prime Rate \| Line of Credit
Debt Instrument [Line Items]
Commitment fee								0.25%
Term Loan A \| Mitsubishi Bank
Debt Instrument [Line Items]
Debt, aggregate principal amount																					$ 4,400,000	¥ 500,000,000
Term Loan A \| Tokyo Interbank Offered Rate (TIBOR) \| Mitsubishi Bank
Debt Instrument [Line Items]
Debt instrument, basis spread	1.40%
Term Loan B \| Mitsubishi Bank
Debt Instrument [Line Items]
Debt, aggregate principal amount																					9,200,000	1,000,000,000
Debt, periodic principal payments \| ¥	¥ 8,300,000
Debt, lump sum payment on the maturity date \| ¥	¥ 8,400,000
Debt issuance costs																					$ 400,000	¥ 40,500,000
Term Loan B \| Tokyo Interbank Offered Rate (TIBOR) \| Mitsubishi Bank
Debt Instrument [Line Items]
Debt instrument, basis spread	1.40%
Mitsubishi Bank Term Loan A \| Notes Payable to Banks
Debt Instrument [Line Items]
Short-term line of credit facility											4,800,000
Repayments of lines of credit				$ 4,400,000	¥ 500,000,000
Mitsubishi Bank Loans \| Notes Payable to Banks
Debt Instrument [Line Items]
Unamortized debt issuance costs											400,000			¥ 48,500,000
Mitsubishi Bank Loan 2017 \| Notes Payable to Banks
Debt Instrument [Line Items]
Short-term line of credit facility										$ 6,400,000										¥ 690,000,000
Debt, aggregate principal amount										$ 6,400,000										¥ 690,000,000
Debt instrument term				72 months	72 months
Long-term debt											4,500,000			488,800,000
Mitsubishi Bank Loan 2017 \| Tokyo Interbank Offered Rate (TIBOR) \| Notes Payable to Banks
Debt Instrument [Line Items]
Debt instrument, basis spread										1.00%
Term Loan C \| Mitsubishi Bank and The Tamanashi Chou Ban, Ltd.
Debt Instrument [Line Items]
Line of credit maximum borrowing capacity				$ 7,800,000													¥ 850,000,000
Debt instrument term				82 months	82 months
Long-term debt											5,900,000			¥ 637,500,000
Term Loan C \| Tokyo Interbank Offered Rate (TIBOR) \| Mitsubishi Bank and The Tamanashi Chou Ban, Ltd.
Debt Instrument [Line Items]
Debt instrument, basis spread				1.00%	1.00%
Notes Payable \| Second Line Of Credit, Expires July 2019 \| Subsidiary in China
Debt Instrument [Line Items]
Short-term line of credit facility											4,300,000				¥ 30,000,000.0
Bankers Acceptance
Debt Instrument [Line Items]
Restricted cash and investments, current											2,500,000	$ 2,600,000
Bankers Acceptance \| Subsidiary in China
Debt Instrument [Line Items]
Outstanding balance of line of credit facilities											$ 0	$ 4,800,000
Bankers Acceptance \| Second Line Of Credit, Expires July 2019 \| Subsidiary in China
Debt Instrument [Line Items]
Percentage of compensating balance requirement for bank acceptance drafts											50.00%
Short-term line of credit facility											$ 8,600,000				60,000,000.0
Line of Credit \| Amended Comerica Bank Credit Facility
Debt Instrument [Line Items]
Current borrowing capacity																			$ 17,000,000.0
Line of credit facility, maximum indebtedness under debt covenant																			$ 20,000,000.0
Notes Payable to Banks \| Note payable to China CITIC Bank
Debt Instrument [Line Items]
Borrowing on line of credit			$ 17,000,000.0						$ 17,000,000.0
Debt instrument, basis spread									2.55%
Stated interest rate			4.70%
Repayments of lines of credit		$ 17,000,000.0
China \| CITIC Bank \| Line of Credit
Debt Instrument [Line Items]
Line of credit maximum borrowing capacity						35,900,000							35,900,000					¥ 250,000,000
China \| CITIC Bank \| Bank Acceptance Drafts
Debt Instrument [Line Items]
Line of credit maximum borrowing capacity						$ 56,100,000							$ 56,100,000					¥ 390,600,000
Percentage of compensating balance requirement for bank acceptance drafts						36.00%
China \| First Credit Facility Expires June 2016
Debt Instrument [Line Items]
Percentage of compensating balance requirement for bank acceptance drafts											50.00%
China \| Notes Payable
Debt Instrument [Line Items]
Number of credit facilities \| debt_instrument											2
China \| Notes Payable \| First Credit Facility Expires June 2016
Debt Instrument [Line Items]
Short-term line of credit facility											$ 17,200,000				120,000,000.0
Borrowing on line of credit							$ 17,000,000.0
China \| Bankers Acceptance \| First Credit Facility Expires June 2016
Debt Instrument [Line Items]
Line of credit maximum borrowing capacity											$ 34,400,000				¥ 240,000,000.0
Debt instrument, basis spread							4.10%
China \| Notes Payable to Banks \| Note payable to China CITIC Bank
Debt Instrument [Line Items]
Repayments of lines of credit				$ 17,000,000.0
United States \| Wells Fargo Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Liquidity requirements under line of credit facility																30,000,000.0
Non-US \| Wells Fargo Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Liquidity requirements under line of credit facility																$ 40,000,000.0
Minimum \| Mitsubishi Bank
Debt Instrument [Line Items]
Interest rate											1.04%	1.05%		1.04%	1.04%
Minimum \| Wells Fargo Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Revolver accounts receivable								80.00%
Minimum \| Wells Fargo Credit Facility \| Credit Facility Base Rate \| Line of Credit
Debt Instrument [Line Items]
Debt instrument, basis spread								1.50%
Minimum \| Wells Fargo Credit Facility \| Prime Rate \| Line of Credit
Debt Instrument [Line Items]
Debt instrument, basis spread								0.50%
Maximum \| Mitsubishi Bank
Debt Instrument [Line Items]
Interest rate											1.44%	1.45%		1.44%	1.44%
Maximum \| Wells Fargo Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Revolver accounts receivable								85.00%
Maximum \| Wells Fargo Credit Facility \| Credit Facility Base Rate \| Line of Credit
Debt Instrument [Line Items]
Debt instrument, basis spread								1.75%
Maximum \| Wells Fargo Credit Facility \| Prime Rate \| Line of Credit
Debt Instrument [Line Items]
Debt instrument, basis spread								0.75%