Stockholders' Equity - Summary of Stockholders' Equity Transactions (Detail) - USD ($)				3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 10, 2019	May 23, 2019	Jul. 30, 2018	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 31, 2019
Beginning balance				$ 2,200,000	$ 3,287,000	$ 1,503,000	$ 6,745,000	$ 6,745,000
Issuance of common Stock for a preferred equity interest in real estate				1,600,000		1,600,000
Issuance of common stock (net of costs)					0		1,421,000
Warrant exercises				2,000		2,479,000
Stock-based compensation				22,000	23,000	65,000	70,000
Net loss				(606,000)	(2,375,000)	(2,429,000)	(7,301,000)	9,200,000
Ending balance				3,218,000	935,000	3,218,000	935,000	1,503,000
Common Stock [Member]
Beginning balance				$ 3,000	$ 1,000	$ 2,000	$ 1,000	$ 1,000
Beginning balance, Shares				2,750,955	550,260	1,773,189	327,060	327,060
Issuance of common Stock for a preferred equity interest in real estate, Shares				400,000		400,000
Conversion of Series E preferred stock to common stock, Shares							53,200
Conversion of Series E preferred stock to common stock							$ 0
Issuance of common stock (net of costs), Shares	1,183,400	11,900	257,142				170,000
Issuance of common stock (net of costs)							$ 0
Warrant exercises, Shares				828		978,594
Warrant exercises				$ 0		$ 1,000
Cancellation of common shares from reverse stock split, Shares				(3)		(3)
Ending balance				$ 3,000	$ 1,000	$ 3,000	$ 1,000	$ 2,000
Ending balance, Shares				3,151,780	550,260	3,151,780	550,260	1,773,189
Capital in Excess of Par Value [Member]
Beginning balance				$ 332,993,000	$ 327,956,000	$ 330,474,000	$ 326,488,000	$ 326,488,000
Issuance of common Stock for a preferred equity interest in real estate				1,600,000		1,600,000
Conversion of Series E preferred stock to common stock							0
Issuance of common stock (net of costs)							1,421,000
Warrant exercises				2,000		2,478,000
Stock-based compensation				22,000	23,000	65,000	70,000
Ending balance				334,617,000	327,979,000	334,617,000	327,979,000	330,474,000
Accumulated Deficit [Member]
Beginning balance				(330,796,000)	(324,670,000)	(328,973,000)	(319,744,000)	(319,744,000)
Net loss				(606,000)	(2,375,000)	(2,429,000)	(7,301,000)
Ending balance				$ (331,402,000)	$ (327,045,000)	$ (331,402,000)	$ (327,045,000)	$ (328,973,000)
Convertible Preferred Stock [Member]
Beginning balance, Shares				328,925	328,925	328,925	330,787	330,787
Conversion of Series E preferred stock to common stock, Shares							(1,862)
Ending balance				$ 0		$ 0
Ending balance, Shares				328,925	328,925	328,925	328,925	328,925