Quarterly report pursuant to Section 13 or 15(d)

Shareholders' Equity - Additional Information (Details)

v3.20.2
Shareholders' Equity - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 9 Months Ended
Dec. 31, 2019
Nov. 08, 2016
Sep. 26, 2020
Sep. 28, 2019
Sep. 26, 2020
Sep. 28, 2019
Nov. 05, 2020
Nov. 04, 2020
Dec. 28, 2019
Dec. 29, 2018
Shareholders Equity [Line Items]                    
Common stock, shares authorized (in shares)     10,000,000   10,000,000       10,000,000  
Common stock, issued shares (in shares)     1,829,982   1,829,982       1,919,048  
Common stock, outstanding shares (in shares)     1,829,982   1,829,982       1,919,048  
Stock issued new during period, shares           223,214        
Stock issued new during period, value           $ 1,000        
Common shares were returned     71,607,000   71,607,000          
Options outstanding     101,900   101,900       44,400 100,900
Options granted         62,000          
Estimated future share-based compensation expense     $ 76   $ 76          
Share-based compensation award amortized period         2021-07          
Warrants outstanding     33,363   33,363       33,363  
Warrant exercise price     $ 3.40   $ 3.40       $ 3.40  
Warrant expiration date         Nov. 30, 2021          
Stock Options                    
Shareholders Equity [Line Items]                    
Stock options, exercisable     56,900   56,900          
Weighted average exercise price, exercisable     $ 12.04   $ 12.04          
Share-based compensation expense     $ 46 $ 91 $ 118 $ 212        
2016 Plan                    
Shareholders Equity [Line Items]                    
Options expiration date         Oct. 28, 2026          
Increased number of shares of common stock reserved for issuance     400,000   400,000          
Options outstanding     66,000   66,000       4,000  
2016 Plan | Employees                    
Shareholders Equity [Line Items]                    
Options granted, vesting period         2 years          
2016 Plan | Non-Employee Directors                    
Shareholders Equity [Line Items]                    
Options granted, vesting period         6 months          
2011 Plan                    
Shareholders Equity [Line Items]                    
Options expiration date         May 12, 2021          
Options outstanding     35,900   35,900       40,400  
Additional awards to be granted after adoption of 2016 plan         0          
Subsequent Event                    
Shareholders Equity [Line Items]                    
Common stock, shares authorized (in shares)             200,000,000      
Subsequent Event | 2016 Plan                    
Shareholders Equity [Line Items]                    
Increased number of shares of common stock reserved for issuance               800,000    
Energy Efficiency Investments LLC Securities Purchase Agreement | Notes Payable                    
Shareholders Equity [Line Items]                    
Debt issuance date   Nov. 08, 2016                
Debt interest rate   3.00%                
Energy Efficiency Investments LLC Securities Purchase Agreement | Notes Payable | Maximum                    
Shareholders Equity [Line Items]                    
Debt face amount   $ 7,732                
Common Stock                    
Shareholders Equity [Line Items]                    
Common shares, returned         122,257          
Common Stock | Energy Efficiency Investments LLC Securities Purchase Agreement                    
Shareholders Equity [Line Items]                    
Common shares, returned 122,257                  
Contractor                    
Shareholders Equity [Line Items]                    
Stock issued for services, shares         104,798 223,214        
Stock issued for services, value         $ 351 $ 1,000        
Articles of Incorporation                    
Shareholders Equity [Line Items]                    
Common stock, shares authorized (in shares)     10,000,000   10,000,000