Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurement - Additional Information (Details)

v3.20.1
Fair Value Measurement - Additional Information (Details) - USD ($)
9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Fair Value Disclosures [Abstract]    
Impairment of property and equipment $ 0 $ 0