Represents the number number of manufacturing facilities assigned.

No definition available.

Name:	nvax_NumberOfManufacturingFacilitiesAssigned
Namespace Prefix:	nvax_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Write-off of amounts previously capitalized as lease liabilities.

+ References

No definition available.

+ Details

Name:	nvax_WriteOffOfLeaseLiabilities
Namespace Prefix:	nvax_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of loss from reductions in right of use assets due to assignment of two of its manufacturing facility leases to Catalent.

+ References

No definition available.

+ Details

Name:	nvax_WriteOffOfRightOfUseAssets
Namespace Prefix:	nvax_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

+ Details

Name:	us-gaap_LesseeOperatingLeaseTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	srt_CounterpartyNameAxis=nvax_CatalentMarylandIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

Leases (Details) $ in Millions	1 Months Ended		12 Months Ended
Leases (Details) $ in Millions	Jul. 31, 2019 facility	Jun. 30, 2019 facility	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Total facility rent expense				$ 5.0	$ 8.4
Catalent Maryland, Inc
Number of manufacturing facilities assigned \| facility	2	2
Write-off of right-of-use assets			$ 8.2
Write-off of lease liabilities			$ 12.7
Maximum [Member]
Operating lease expiration			7 years
Minimum [Member]
Operating lease expiration			4 years