Background and Organization - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Net loss	$ (27,532)	$ (33,361)
Net cash used from operations	(34,999)	$ (23,653)
Cash and cash equivalents	$ 190,208		$ 226,783