Organization and Business - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Net loss	$ 39,292	$ 27,824	$ 19,072	$ 19,953	$ 67,116	$ 39,025
Cash used in operations					43,686	$ 27,702
Accumulated deficit	256,600				256,600		$ 189,484
Cash, cash equivalents and marketable securities	$ 454,900				$ 454,900