Stockholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2014
Subsidiary, Sale of Stock [Line Items]
Available proceeds under ATM	$ 15,000
Maximum [Member]
Subsidiary, Sale of Stock [Line Items]
Common stock authorized for issuance under prior shelf registration statement with SEC, dollar amount	$ 50,000

Common stock authorized for issuance under prior shelf registration statement with SEC, dollar amount.

No definition available.

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