Discontinued Operations (Details)		3 Months Ended		6 Months Ended
	Jun. 29, 2018 USD ($) contract	Oct. 27, 2018 USD ($)	Oct. 28, 2017 USD ($)	Oct. 27, 2018 USD ($)	Oct. 28, 2017 USD ($)
Statement of operations
Net loss from discontinued operations		$ (599,000)	$ (33,000)	$ (2,449,000)	$ (1,521,000)
(Loss) gain on sale of business, net of tax (benefit) expense of $(114) and $2,463 for the three and six months ended October 27, 2018, respectively		(391,000)		8,452,000
Tax expense		(114,000)	0	2,463,000	0
Net (loss) income from discontinued operations		(990,000)	(33,000)	6,003,000	(1,521,000)
EES Business | Disposed of by sale
Discontinued operations
Cash consideration received	$ 31,994,000
Gain on sale of business	11,420,000	(504,000)
Working capital dispute		1,085,000
Amounts recorded in the consolidated financial statements		0
EES Business | Disposed of by sale | Other income
Statement of operations
Net Sales		1,221,000		1,620,000
EES Business | Discontinued Operations
Statement of operations
Net Sales			9,965,000	4,256,000	17,575,000
Cost of sales		748,000	8,293,000	5,026,000	14,803,000
Gross margin		(748,000)	1,672,000	(770,000)	2,772,000
Selling, general and administrative		50,000	1,696,000	1,503,000	3,740,000
Research and development		(25,000)	429,000	1,040,000	1,348,000
Other income, net				1,000
Loss from discontinued operations before income taxes		(773,000)	(453,000)	(3,312,000)	(2,316,000)
Benefit for income taxes		(174,000)	(420,000)	(863,000)	(795,000)
Net loss from discontinued operations		(599,000)	(33,000)	(2,449,000)	(1,521,000)
(Loss) gain on sale of business, net of tax (benefit) expense of $(114) and $2,463 for the three and six months ended October 27, 2018, respectively		(391,000)		8,452,000
Tax expense		(114,000)		2,463,000
Net (loss) income from discontinued operations		$ (990,000)	$ (33,000)	$ 6,003,000	$ (1,521,000)
Holdback | Disposed of by sale
Discontinued operations
Cash consideration received	$ 6,500,000
Number of remaining contracts | contract	2