Asset pledged to bank to obtain loan facilities.

No definition available.

Name:	ntpif_AssetPledgedToBankToObtainLoanFacilities
Namespace Prefix:	ntpif_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Lease contract beginning date.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Operating lease rent free incentive period.

+ References

No definition available.

+ Details

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Namespace Prefix:	ntpif_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

+ References

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+ Details

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Period Type:	duration

- Definition

Term of lessor's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

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+ Details

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- 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

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- Details

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- Details

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Property, Plant and Equipment, Net - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2018	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Buildings
Property, Plant and Equipment [Line Items]
Asset pledged to banks to obtain loan facilities						$ 12.8
Buildings \| Wuxi Zastron Precision-Flex Co., Ltd. (Wuxi Zastron-Flex)
Property, Plant and Equipment [Line Items]
Lease expiration term	12 years
Operating lease rent free incentive period	10 months
Beginning date of lease term	Feb. 01, 2019
Property, plant and equipment
Property, Plant and Equipment [Line Items]
Depreciation expenses		$ 0.8	$ 0.9	$ 1.2	$ 1.6	$ 1.6	$ 1.2