XML 85 R70.htm IDEA: XBRL DOCUMENT v3.22.1

Fair Value Measurements - company's financial assets and liabilities that are measured at fair value on a recurring basis (Details) - Recurring - SPRING VALLEY ACQUISITION CORP - USD ($)	Mar. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Level 1
Assets, Fair Value Disclosure [Abstract]
Investments held in Trust Account - Mutual funds	$ 232,344,333	$ 232,320,939	$ 232,301,973
Public Warrants | Level 1
Liabilities:
Derivative Warrant Liabilities, Fair Value Disclosure	22,540,000	14,375,000
Private Placement Warrant | Level 1
Liabilities:
Derivative Warrant Liabilities, Fair Value Disclosure		14,375,000	18,975,000
Private Placement Warrant | Level 2
Liabilities:
Derivative Warrant Liabilities, Fair Value Disclosure	$ 17,444,000
Private Placement Warrant | Level 3
Liabilities:
Derivative Warrant Liabilities, Fair Value Disclosure		$ 14,774,000	$ 14,685,000

X

- Definition

Fair value portion of derivative warrant liabilities.

+ References

No definition available.

+ Details

Name:	svsvu_DerivativeWarrantLiabilitiesFairValueDisclosure
Namespace Prefix:	svsvu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- References

No definition available.

+ Details

Name:	us-gaap_AssetsFairValueDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

+ Details

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

X

- References

No definition available.

+ Details

Name:	us-gaap_LiabilitiesFairValueDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=svsvu_SpringValleyAcquisitionCorpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=svsvu_PublicWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=svsvu_PrivatePlacementWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: