XML 22 R35.htm IDEA: XBRL DOCUMENT v3.19.3
Fair Value of Financial Instruments - Fair value of the warrants (Details)
$ in Thousands
9 Months Ended 12 Months Ended
Jun. 07, 2019
Sep. 30, 2019
USD ($)
item
shares
Dec. 31, 2018
item
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Reverse stock split 0.167   0.167
Warrant liability, measurement input   17.00  
Warrants to purchase (in shares) | shares   49,997  
Reclassification of redeemable convertible preferred stock warrant liability to additional paid-in capital | $   $ 503  
Expected life   3 years 2 months 1 day 3 years 7 months 21 days
Exercise price (1)      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Warrant liability, measurement input     14.46
Stock price (2)      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Warrant liability, measurement input     13.20
Volatility (3)      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Warrant liability, measurement input   0.8361 0.837
Risk-free interest rate (4)      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Warrant liability, measurement input   0.0169 0.0250
Expected dividend      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Warrant liability, measurement input   0.00