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v3.23.2

Marketable Securities - Fair Value to Amortized Cost (Details) - USD ($) | 12 Months Ended
--- | ---
Jun. 30, 2023 | Jun. 30, 2022
Marketable Securities: |  |
Transfers between Level 1 to 2 | $ 0 | $ 0
Transfers in or out of level 3 | $ 0 | $ 0

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- Definition Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2. + References No definition available. + Details
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Namespace Prefix: | nssc_
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Balance Type: | credit
Period Type: | duration

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- Definition Amount of transfers of marketable securities for level 3. + References No definition available. + Details
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Namespace Prefix: | nssc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-3 + Details
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Balance Type: | na
Period Type: | duration