Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Additional Information (Details)

v3.19.3
Stockholders' Equity - Additional Information (Details) - USD ($)
1 Months Ended 3 Months Ended 9 Months Ended
May 14, 2019
Jan. 22, 2019
Sep. 30, 2019
Aug. 31, 2019
Jul. 31, 2019
May 31, 2019
Mar. 31, 2019
Feb. 28, 2019
Jan. 31, 2019
Sep. 30, 2019
Sep. 30, 2019
Feb. 26, 2019
Public offering (in shares) 11,000,000 5,175,000                    
Public offering price (in dollars per share) $ 2.00 $ 1.90                    
Gross proceeds from public offering $ 22,000,000 $ 9,800,000                    
Net proceeds from public offering $ 20,300,000 $ 9,100,000                    
Expected vesting period                   3 years 6 months 3 years 6 months  
2019 Plan, Option One                        
Shares available from award (in shares)         150,000              
Award exercise period         5 years              
Award exercise price (in dollars per share)         $ 1.65              
Expected vesting period         3 years              
2019 Plan, Option Two                        
Shares available from award (in shares)         50,000              
Award exercise period         5 years              
Award exercise price (in dollars per share)         $ 1.87              
Expected vesting period         3 years              
Chief Financial Officer                        
Shares available from award (in shares)             250,000   56,698      
Award exercise period                 5 years      
Award exercise price (in dollars per share)                 $ 1.88      
Expected vesting period             3 years          
Chief Financial Officer | Option One                        
Shares available from award (in shares)             125,000          
Award exercise period             5 years          
Award exercise price (in dollars per share)             $ 3.79          
Chief Financial Officer | Option Two                        
Shares available from award (in shares)             62,500          
Award exercise period             5 years          
Award exercise price (in dollars per share)             $ 4.39          
Chief Financial Officer | Option Three                        
Shares available from award (in shares)             62,500          
Award exercise period             5 years          
Award exercise price (in dollars per share)             $ 4.89          
Share-based Compensation Award, Tranche One | Chief Financial Officer                        
Award exercise percentage             33.33%          
Share-based Compensation Award, Tranche Two | Chief Financial Officer                        
Award exercise percentage             33.33%          
Share-based Compensation Award, Tranche Three | Chief Financial Officer                        
Award exercise percentage             33.33%          
Affiliated Entity                        
Warrant terms                       10 years
Affiliated Entity | Operations, Management and Maintenance Contract Year One                        
Warrant exercise price (in dollars per share)                       $ 5.00
Number of shares issued at anniversary (in shares)                       2,000,000
Affiliated Entity | Operations, Management and Maintenance Contract Year Two                        
Warrant exercise price (in dollars per share)                       $ 7.00
Number of shares issued at anniversary (in shares)                       2,000,000
Warrant                        
Warrants issued (in shares)   103,500                    
Percentage of warrants issued   2.00%                    
Total shares sold   $ 5,175,000                    
Warrant exercise price (in dollars per share)   $ 1.90                    
Percentage of warrant exercise price   100.00%                    
Post-modification warrant expiration date                     Jan. 22, 2024  
Restricted Stock Units (RSUs)                        
Award exercise period                 3 years      
Restricted stock units granted (in shares)     59,414 134,419         261,455      
Restricted stock units grant date fair value     $ 109,000 $ 231,000         $ 490,000      
Restricted Stock Units (RSUs) | Share-based Compensation Award, Tranche One                        
Award exercise percentage                 16.67%      
Restricted Stock Units (RSUs) | Share-based Compensation Award, Tranche Two                        
Award exercise percentage                 16.67%      
Restricted Stock Units (RSUs) | Share-based Compensation Award, Tranche Three                        
Award exercise percentage                 16.67%      
Restricted Stock Units (RSUs) | Share-based Compensation Award, Tranche Four                        
Award exercise percentage                 16.67%      
Restricted Stock Units (RSUs) | Share-based Compensation Award, Tranche Five                        
Award exercise percentage                 16.67%      
Restricted Stock Units (RSUs) | Share-based Compensation Award, Tranche Six                        
Award exercise percentage                 16.67%      
Prior Company Executives | Common Stock                        
Common stock issued during period (in shares)                     233,646  
Board Members | 2019 Plan                        
Shares available from award (in shares)           172,915            
Award exercise period           5 years            
Award exercise price (in dollars per share)           $ 2.48            
Expected vesting period           12 months            
Board Members | Common Stock                        
Common stock issued during period (in shares)                     142,345  
Board Members | Restricted Stock Units (RSUs)                        
Restricted stock units granted (in shares)         60,560              
Restricted stock units grant date fair value         $ 97,500              
Veolia North America Regeneration Services, LLC                        
Common stock value                     $ 2,700,000  
Veolia North America Regeneration Services, LLC | Common Stock                        
Common stock issued during period (in shares)                     891,235  
Prior Company Executives | Common Stock                        
Common stock issued during period (in shares)                     110,775  
Clarios                        
Common stock value                     $ 1,300,000  
Clarios | Common Stock                        
Common stock issued during period (in shares)                     807,436  
Stephen Cotton | Chief Executive Officer                        
Shares available from award (in shares)               1,260,000.00 232,461      
Award exercise period                 5 years      
Award exercise price (in dollars per share)                 $ 1.88      
Expected vesting period               3 years        
Stephen Cotton | Chief Executive Officer | Option One                        
Shares available from award (in shares)               420,000        
Award exercise period               5 years        
Award exercise price (in dollars per share)               $ 3.08        
Stephen Cotton | Chief Executive Officer | Option Two                        
Shares available from award (in shares)               420,000        
Award exercise period               5 years        
Award exercise price (in dollars per share)               $ 3.68        
Stephen Cotton | Chief Executive Officer | Option Three                        
Shares available from award (in shares)               420,000        
Award exercise period               5 years        
Award exercise price (in dollars per share)               $ 4.18        
Stephen Cotton | Share-based Compensation Award, Tranche One | Chief Executive Officer                        
Award exercise percentage               33.33%        
Stephen Cotton | Share-based Compensation Award, Tranche Two | Chief Executive Officer                        
Award exercise percentage               33.33%        
Stephen Cotton | Share-based Compensation Award, Tranche Three | Chief Executive Officer                        
Award exercise percentage               33.33%