Document and Entity Information	3 Months Ended
	Mar. 31, 2013	May 03, 2013
Document And Entity Information
Entity Registrant Name	KRATOS DEFENSE & SECURITY SOLUTIONS, INC.
Entity Central Index Key	0001069258
Current Fiscal Year End Date	--12-29
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		56,668,864