Quarterly report pursuant to Section 13 or 15(d)

Nature of Business - Additional Information (Details)

v3.20.2
Nature of Business - Additional Information (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]              
Net Loss $ 19,486 $ 19,793 $ 53,908 $ 55,709 $ 75,400 $ 62,300 $ 54,000
Accumulated deficit (346,891)   (346,891)   (292,983)    
Cash and cash equivalents $ 93,133 $ 33,364 $ 93,133 $ 33,364 $ 41,441 $ 49,886