Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity - Additional Information (Details)

v3.20.1
Shareholders' Equity - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 28, 2019
Dec. 29, 2018
Dec. 30, 2017
Shareholders Equity [Line Items]      
Common stock, shares authorized (in shares) 10,000,000 10,000,000  
Share-based compensation, shares 224,483    
Share based compensation, value $ 500    
Common stock, issued shares (in shares) 1,919,048 1,694,565  
Common stock, outstanding shares (in shares) 1,919,048 1,694,565  
Options outstanding 44,400 100,900 125,500
Options issued 0 0  
Warrants outstanding 33,363 33,363  
Warrant exercise price $ 3.40 $ 3.40  
Warrant expiration date May 31, 2020 May 31, 2020  
Stock Options      
Shareholders Equity [Line Items]      
Share-based compensation expense $ 631 $ 656  
2016 Plan      
Shareholders Equity [Line Items]      
Options expiration date Oct. 28, 2026    
Options authorized for issuance 400,000    
Options outstanding 4,000 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 40,400 96,900  
Additional awards to be granted after adoption of 2016 plan 0    
Contractor      
Shareholders Equity [Line Items]      
Stock issued for services, shares   274,834  
Stock issued for services, value   $ 919  
Energy Efficiency Investments      
Shareholders Equity [Line Items]      
Shares issued in conversion, shares   44,623  
Shares issued in conversion, value   $ 101  
Articles of Incorporation      
Shareholders Equity [Line Items]      
Common stock, shares authorized (in shares) 10,000,000