Document and Entity Information - shares	6 Months Ended
	Dec. 31, 2015	Jan. 31, 2016
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q2
Trading Symbol	MRCY
Entity Registrant Name	MERCURY SYSTEMS INC
Entity Central Index Key	0001049521
Current Fiscal Year End Date	--06-30
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		34,829,997