Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Narrative (Details)

v3.19.3
Stock-Based Compensation - Narrative (Details)
1 Months Ended
Nov. 07, 2018
USD ($)
solar_energy_system_install
Aug. 31, 2017
USD ($)
solar_energy_system_install
vesting_increment
$ / shares
shares
May 30, 2017
USD ($)
purchase_period
shares
Nov. 08, 2019
shares
Subsequent event        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Warrant, vested (in shares) | shares       0
Warrants        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Warrant, term   40 months    
Warrant, number purchased (in shares) | shares   11,793,355    
Warrant, exercise price (in dollars per share) | $ / shares   $ 0.01    
Warrant, vesting percentage   50.05%    
Warrant, milestone one, solar energy systems | solar_energy_system_install 6,000 30,000    
Warrant, milestone two, marketing and sales dollars | $   $ 10,000,000.0    
Warrant, vesting increments | vesting_increment   5    
Warrant, milestone two, solar energy systems | solar_energy_system_install 8,000 6,000    
Warrant, vesting percentage, milestone one 10.00%      
Warrant, vesting percentage, milestone two 13.30%      
Warrant, milestone one and two, marketing and sales dollars | $ $ 25,000,000.0      
Warrant, vesting percentage, milestone three 8.30%      
Warrant, milestone three, solar energy systems | solar_energy_system_install 5,000      
Employee Stock Purchase Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
ESPP offering period     24 months  
Number of purchase periods | purchase_period     4  
Maximum percentage in payroll deductions to acquire shares of common stock     15.00%  
Maximum deductible fair market value of shares available for employee to purchase per calendar year | $     $ 25,000  
Maximum number of shares available for employee to purchase per offering period (in shares) | shares     10,000