Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Schedule of Market-based Assumptions (Details)

v3.19.2
Fair Value Measurements - Schedule of Market-based Assumptions (Details)
3 Months Ended
Jun. 30, 2019
$ / shares
Mar. 31, 2019
$ / shares
Jun. 30, 2018
$ / shares
Mar. 31, 2018
$ / shares
Dec. 31, 2017
$ / shares
Sep. 30, 2017
$ / shares
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]            
Stock price (in dollars per share) $ 5.00 $ 3.50 $ 1.51 $ 2.01 $ 1.51 $ 2.01
CCE interest rate 1.90%          
Warrant liability            
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]            
Stock price (in dollars per share) $ 5.00          
Stock price volatility | Warrant liability            
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]            
Embedded derivative liability, measurement input (as a percent) 0.60          
Expected term | Warrant liability            
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]            
Expected term 1 year 2 months 25 days          
Risk-free interest rate | Warrant liability            
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]            
Embedded derivative liability, measurement input (as a percent) 0.0186