Acquisition of Isconova AB (Narrative) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended								12 Months Ended					5 Months Ended	12 Months Ended
	Jul. 31, 2013	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Collaboration Agreement [Member]	Dec. 31, 2013 Proprietary Adjuvant Technology [Member]	Dec. 31, 2013 Novavax AB [Member]	Dec. 31, 2013 Minimum [Member]	Dec. 31, 2013 Maximum [Member]
Business Acquisition [Line Items]
Novavax shares issued for Isconova AB shares acquired	15,600,000
Value of shares of Novavax Common Stock issued	$ 41,942
Cash paid to Isconova warrant holders	22
Acquired finite-lived intangible assets, weighted-average useful life										17 years			12 years	20 years		7 years	20 years
Goodwill	26,236
Revenue		8,748	4,802	3,531	3,833	4,567	5,765	7,103	4,642	20,915	22,076	14,688			700
Net loss										(51,983)	(28,507)	(19,364)			(3,500)
Transaction costs										1,300
Other non-current liabilities		$ 1,568								$ 1,568