Notes Payable (Aggregate Future Minimum Principal Payments on Equipment Loan) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013
Notes Payable [Abstract]
2013 (remainder)	$ 293
2014	390
2015	390
2016	207
Total	$ 1,280

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

No definition available.

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