v3.19.3
Long-Term Debt - Additional Information - Convertible Notes (Details) - USD ($)
1 Months Ended 9 Months Ended
Aug. 31, 2018
Sep. 30, 2019
Sep. 30, 2018
Jun. 29, 2018
Jun. 28, 2018
Apr. 02, 2018
Feb. 09, 2018
Debt Instrument [Line Items]              
Outstanding convertible promissory notes and accrued interest converted, amount   $ 0 $ 14,898,326        
Convertible notes outstanding   $ 0          
Convertible Notes              
Debt Instrument [Line Items]              
Outstanding convertible promissory notes and accrued interest converted, amount $ 14,900,000            
Convertible Notes | Common Stock              
Debt Instrument [Line Items]              
Outstanding convertible promissory notes and accrued interest converted, shares 3,239,294            
Note Purchase Agreement | Convertible Notes              
Debt Instrument [Line Items]              
Increase the principal amount available for issuance       $ 19,400,000 $ 18,400,000 $ 18,400,000  
Note Purchase Agreement | Convertible Notes | Maximum              
Debt Instrument [Line Items]              
Original principal amount             $ 16,000,000