Organization and Summary of Significant Accounting Policies (Details)	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2017 USD ($)	Oct. 01, 2017 USD ($) Segment	Dec. 31, 2017 USD ($) Segment type_of_contract $ / shares	Dec. 25, 2016 USD ($) $ / shares	Dec. 27, 2015 USD ($) $ / shares	Sep. 25, 2016 USD ($)
Significant Accounting Policies Disclosure [Line Items]
Number of reportable segments | Segment		3	3
Fiscal year duration			371 days	364 days	364 days
Number of different types of contractual arrangements | type_of_contract			3
Number of basic categories of fixed price contracts | type_of_contract			3
Accruals for losses on contracts	$ 10,300,000		$ 10,300,000	$ 17,700,000
Share-based Compensation
Employee Stock Purchase Plan offering & expense recognition period			6 months
Incremental tax benefits from exercise of stock options			$ 0	$ 0	$ 0
Impact on net loss per common share, basic and diluted (in dollars per share) | $ / shares			$ (0.09)	$ (0.08)	$ (0.10)
Allowance for Doubtful Accounts
Provisions			$ 100,000	$ 300,000	$ 400,000
Cash and Cash Equivalents
Restricted cash	400,000		400,000	500,000
Interest Expense, Net
Interest expense incurred primarily on the Company’s Senior Secured Notes			(29,100,000)	(34,700,000)	(36,000,000)
Miscellaneous interest income			500,000	0	0
Interest expense, net			(28,600,000)	(34,700,000)	(36,000,000)
Foreign Currency
Foreign currency transaction gain (loss)			$ 400,000	400,000	(800,000)
Minimum
Significant Accounting Policies Disclosure [Line Items]
Fiscal year duration			364 days
Share-based Compensation
Share-based incentive award vesting period			5 years
Goodwill and Other Intangible Assets, Net
Useful life of finite-lived intangible assets			1 year
Maximum
Significant Accounting Policies Disclosure [Line Items]
Fiscal year duration			371 days
Share-based Compensation
Share-based incentive award vesting period			10 years
Goodwill and Other Intangible Assets, Net
Useful life of finite-lived intangible assets			15 years
Buildings and improvements | Minimum
Property and Equipment, Net
Useful life of property and equipment			15 years
Buildings and improvements | Maximum
Property and Equipment, Net
Useful life of property and equipment			39 years
Machinery and equipment | Minimum
Property and Equipment, Net
Useful life of property and equipment			3 years
Machinery and equipment | Maximum
Property and Equipment, Net
Useful life of property and equipment			10 years
Computer equipment and software | Minimum
Property and Equipment, Net
Useful life of property and equipment			1 year
Computer equipment and software | Maximum
Property and Equipment, Net
Useful life of property and equipment			10 years
Vehicles, furniture, and office equipment | Maximum
Property and Equipment, Net
Useful life of property and equipment			5 years
Allowance for Doubtful Accounts
Allowance for Doubtful Accounts
Balance at Beginning of Year		$ 1,700,000	$ 1,700,000	1,800,000	1,900,000
Provisions			100,000	300,000	400,000
Write-offs/Recoveries			(1,200,000)	(400,000)	(500,000)
Balance at End of Year	600,000		600,000	1,700,000	1,800,000
Continuing operations
Share-based Compensation
Stock-based compensation expense, amount recognized in the consolidated financial statements			7,800,000	5,100,000	6,100,000
Selling, general and administrative expenses
Share-based Compensation
Stock-based compensation expense, amount recognized in the consolidated financial statements			7,800,000	5,100,000	$ 6,100,000
Revenue | Accounting Standards Update 2014-09
Recent Accounting Pronouncements
Cumulative effect of adopting ASU 2014-09, less than	2,000,000		2,000,000
Operating Income | Accounting Standards Update 2014-09
Recent Accounting Pronouncements
Cumulative effect of adopting ASU 2014-09, less than	2,000,000		2,000,000
Kratos Government Solutions (KGS)
Recent Accounting Pronouncements
Impairment of goodwill	24,200,000		$ 24,200,000
Kratos Government Solutions (KGS) | Building facility
Property and Equipment, Net
Carrying value of building held-for-sale						$ 1,900,000
Remeasured fair value of building held-for-sale				500,000
Impairment loss on building reclassified from held-for-sale to held				1,400,000
Stock options | Maximum
Share-based Compensation
Share-based incentive award vesting period			6 years
Purchase order not received
Significant Accounting Policies Disclosure [Line Items]
Accounts receivable	$ 1,900,000		$ 1,900,000	$ 2,000,000