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	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Significant Accounting Policies [Line Items]
Net income (loss)-basic and diluted	$ 7,729	$ (18,000)	$ (22,645)
Weighted average shares outstanding-basic	395,992	381,759	342,538
Weighted average shares outstanding-diluted	402,480	381,759	342,538
Net earnings (loss) per share-basic	$ 0.02	$ (0.05)	$ (0.07)
Net earnings (loss) per share-diluted	$ 0.02	$ (0.05)	$ (0.07)
Stock Options
Significant Accounting Policies [Line Items]
Effect of dilutive securities	4,420
Restricted Stock and Restricted Stock Units
Significant Accounting Policies [Line Items]
Effect of dilutive securities	2,068