Earnings Per Common Share ("EPS") - Components of Basic and Diluted EPS Computations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
EPS — basic and diluted:
Net loss (numerator)	$ (35,523)	$ (12,916)	$ (10,252)	$ (9,322)	$ (48,439)	$ (19,574)
Weighted average common shares (denominator)	249,295		213,880		247,970	212,943
Net loss per share	$ (0.14)		$ (0.05)		$ (0.20)	$ (0.09)