Significant Accounting Policies - Calculation of Net Income (Loss) and Number of Shares Used to Compute Basic and Diluted Net Earnings (Loss) per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Loss Per Share [Line Items]
Net income (loss)-basic and diluted	$ 7,808	$ 4,415	$ 6,182	$ (16,138)
Weighted average shares outstanding-basic	395,899	384,663	395,272	373,300
Effect of dilutive securities:
Preferred stock, if converted		6,989
Weighted average shares outstanding-diluted	401,767	399,664	402,778	373,300
Net earnings (loss) per share-basic	$ 0.02	$ 0.01	$ 0.02	$ (0.04)
Net earnings (loss) per share-diluted	$ 0.02	$ 0.01	$ 0.02	$ (0.04)
Stock Options
Effect of dilutive securities:
Effect of dilutive securities	4,212	6,372	4,993
Restricted Stock and Restricted Stock Units
Effect of dilutive securities:
Effect of dilutive securities	1,656	1,640	2,513