Notes Payable (Aggregate Future Minimum Principal Payments on Equipment Loan)(Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Notes Payable [Abstract]
2012	$ 39
2013	157
2014	157
2015	157
2016	40
Total	$ 550

Amount of minimum loan payments.

No definition available.

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Amount of minimum loan payments maturing in the fourth rolling twelve months following the latest balance sheet presented.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of minimum loan payments maturing in the third rolling twelve months following the latest balance sheet presented.

No definition available.

Name:	nvax_LoanAgreementFutureMinimumPaymentsDueInRollingYearThree
Namespace Prefix:	nvax_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of minimum loan payments maturing in the second rolling twelve months following the latest balance sheet presented.

No definition available.

Name:	nvax_LoanAgreementFutureMinimumPaymentsDueInRollingYearTwo
Namespace Prefix:	nvax_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of minimum loan payments maturing in the next rolling twelve months following the latest balance sheet presented.

No definition available.

Name:	nvax_LoanAgreementFutureMinimumPaymentsNextRollingTwelveMonths
Namespace Prefix:	nvax_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of minimum loan payments maturing in the remainder of the fiscal year following the latest fiscal year ended.

No definition available.

Name:	nvax_LoanAgreementFutureMinimumPaymentsRemainderOfFiscalYear
Namespace Prefix:	nvax_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration