Summary of Significant Accounting Policies - Additional Information (Detail)			3 Months Ended					6 Months Ended		12 Months Ended
	Jan. 28, 2020	Jul. 24, 2018	Jun. 27, 2020 USD ($) shares	Mar. 28, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 29, 2019 USD ($)	Jun. 27, 2019 shares	Jun. 27, 2020 USD ($) shares	Jun. 29, 2019 USD ($) shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Accumulated deficit			$ 330,796,000		$ 328,973,000			$ 330,796,000		$ 328,973,000
Incurred net loss			(744,000)			$ (2,591,000)		(1,823,000)	$ (4,926,000)	(9,200,000)
Negative cash flows from operations								(2,030,000)	(4,569,000)	(8,800,000)
Cash and cash equivalents			2,382,000		713,000	$ 2,468,000		2,382,000	$ 2,468,000	713,000	$ 5,616,000
Reverse split		1-for-10
Reverse split conversion ratio		0.1
Finance leases			0					0
Inventory, net			68,000		263,000			$ 68,000		263,000
Minimum percentage of tax benefit realized								50.00%
Liabilities for uncertain tax positions			0					$ 0
Interest or penalties on uncertain tax positions								$ 0
U.S. statutory corporate tax rate								21.00%
Deferred tax assets			$ 0		0			$ 0		0
Stock options granted during the period | shares			0				0	0	0
Warrants Exercise								$ 2,477,000
Percentage of Cost Reduction Employee Workforce	70.00%
Net cash proceedsfrom the sale of our common and preferred shares and warrants										3,900,000
Wire inventory expensed			$ 0	$ 190,000				190,000	0
Gain on sale of production wire equipment			0	510,000				$ 510,000	$ 0
Warrants [Member]
Summary Of Significant Accounting Policies [Line Items]
Warrant exercises, Shares | shares								9,777,656
Warrants Exercise			1,100,000		99,000			$ 2,500,000
Furniture and Fixtures [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life								7 years
Patents and Licenses [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives								17 years
Impairment of Intangible Assets			$ 0	$ 134,000
Minimum [Member] | Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life								3 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Term of lease			12 months					12 months
Maximum [Member] | Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life								5 years
State [Member]
Summary Of Significant Accounting Policies [Line Items]
Open tax year								2013
State [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Reduction of taxable income										17,900,000
Federal [Member]
Summary Of Significant Accounting Policies [Line Items]
Open tax year								2014
Net operating loss carryforwards					$ 342.4					$ 342.4
Earliest Tax Year [Member]
Summary Of Significant Accounting Policies [Line Items]
Operating loss carryforwards expiration period								2020
Latest Tax Year [Member]
Summary Of Significant Accounting Policies [Line Items]
Operating loss carryforwards expiration period								2038