Revenues (Impact on Statement of Operating Cash Flows) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income (loss) from continuing operations	$ (6,190,000)	$ (12,448,000)	$ (15,064,000)	$ (23,363,000)
Intangibles amortization			2,153,000	3,551,000
Depreciation	1,983,000	2,167,000	4,111,000	4,499,000
Loss (gain) on sale of property			74,000	36,000
Deferred taxes			(8,286,000)	(3,056,000)
Stock compensation expense			1,446,000	3,108,000
Asset impairment loss	$ 1,586,000	$ 1,426,000	1,586,000	1,426,000
Provision for obsolete inventory			1,073,000	262,000
Provision for (recovery of) doubtful accounts			291,000	518,000
Accounts receivable			(2,865,000)	9,011,000
Inventories			4,208,000	(3,248,000)
Costs/estimated earnings in excess of billings on uncompleted contracts			(5,789,000)	1,561,000
All other assets			4,373,000	(3,083,000)
Accounts payable			(2,529,000)	3,050,000
Billings in excess of costs/estimated earnings on uncompleted contracts			(319,000)	(1,970,000)
All other liabilities			5,256,000	(8,240,000)
Net cash provided by (used for) continuing operating activities			(10,281,000)	$ (15,938,000)
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income (loss) from continuing operations			119,000
Intangibles amortization			0
Depreciation			0
Loss (gain) on sale of property			0
Deferred taxes			0
Stock compensation expense			0
Asset impairment loss			0
Provision for obsolete inventory			0
Provision for (recovery of) doubtful accounts			0
Accounts receivable			7,000
Inventories			(6,000)
Costs/estimated earnings in excess of billings on uncompleted contracts			19,000
All other assets			10,000
Accounts payable			0
Billings in excess of costs/estimated earnings on uncompleted contracts			(8,000)
All other liabilities			(141,000)
Net cash provided by (used for) continuing operating activities			0
Calculated under Revenue Guidance in Effect before Topic 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income (loss) from continuing operations			(14,945,000)
Intangibles amortization			2,153,000
Depreciation			4,111,000
Loss (gain) on sale of property			74,000
Deferred taxes			(8,286,000)
Stock compensation expense			1,446,000
Asset impairment loss			1,586,000
Provision for obsolete inventory			1,073,000
Provision for (recovery of) doubtful accounts			291,000
Accounts receivable			(2,858,000)
Inventories			4,202,000
Costs/estimated earnings in excess of billings on uncompleted contracts			(5,770,000)
All other assets			4,383,000
Accounts payable			(2,529,000)
Billings in excess of costs/estimated earnings on uncompleted contracts			(327,000)
All other liabilities			5,115,000
Net cash provided by (used for) continuing operating activities			$ (10,281,000)