Number of consecutive trading days.

No definition available.

Name:	novn_NumberOfConsecutiveTradingDays
Namespace Prefix:	novn_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of tranches tiered with performance plan.

+ References

No definition available.

+ Details

Name:	novn_NumberOfTranchesTieredWithPerformancePlan
Namespace Prefix:	novn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Performance plan, target bonus pool amount for first tranche.

+ References

No definition available.

+ Details

Name:	novn_PerformancePlanTargetBonusPoolAmountForFirstTranche
Namespace Prefix:	novn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Performance plan, target bonus pool amount for second tranche.

+ References

No definition available.

+ Details

Name:	novn_PerformancePlanTargetBonusPoolAmountForSecondTranche
Namespace Prefix:	novn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Performance plan, target payment term.

+ References

No definition available.

+ Details

Name:	novn_PerformancePlanTargetPaymentTerm
Namespace Prefix:	novn_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Performance plan, target share price for first tranche.

+ References

No definition available.

+ Details

Name:	novn_PerformancePlanTargetSharePriceForFirstTranche
Namespace Prefix:	novn_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Performance plan, target share price for second tranche.

+ References

No definition available.

+ Details

Name:	novn_PerformancePlanTargetSharePriceForSecondTranche
Namespace Prefix:	novn_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

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

- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

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

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

- Details

Name:	us-gaap_PlanNameAxis=novn_TangibleStockholderReturnPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsByTypeOfDeferredCompensationAxis=us-gaap_DeferredBonusMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_TitleOfIndividualAxis=srt_ExecutiveOfficerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_TitleOfIndividualAxis=novn_EmployeesAndConsultantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Tangible Stockholder Return Plan - Additional Information (Details) $ / shares in Units, $ in Thousands		12 Months Ended
	Aug. 02, 2018 USD ($) tranche $ / shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated dividend yield		0.00%	0.00%
Share-based compensation expense		$ 1,838	$ 2,204
Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated dividend yield		0.00%	0.00%
Share-based compensation expense		$ 291	$ 57
Performance Plan \| Deferred Bonus
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of tranches \| tranche	2
Number of consecutive trading days	30 days
Share price target, first tranche (in USD per share) \| $ / shares	$ 11.17
Bonus pool, first tranche	$ 25,000
Share price target, second tranche (in USD per share) \| $ / shares	$ 25.45
Bonus pool, second tranche	$ 50,000
Executive Officer \| Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Bonus award payment term	24 months
Employees And Consultants \| Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Bonus award payment term	12 months