Activity Under Equity Incentive Plans Related to RSUs (Detail) - 2008 Equity Incentive Plan - Restricted Stock Units shares in Thousands	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Activity under the Company's equity incentive plans related to restricted stock units
Number of Restricted Stock Units Unvested, Beginning Balance | shares	6,689
Granted, Number of Restricted Stock Units Unvested | shares	5,034	[1]
Vested, Number of Restricted Stock Units Unvested | shares	(2,848)	[1]
Forfeited, Number of Restricted Stock Units Unvested | shares	(566)	[1]
Number of Restricted Stock Units Unvested, Ending Balance | shares	8,309
Weighted Average Exercise Price per Share
Weighted Average Exercise Price per Share, Beginning Balance | $ / shares	$ 5.90
Granted, Weighted Average Exercise Price per Share | $ / shares	5.65	[1]
Vested, Weighted Average Exercise Price per Share | $ / shares	5.66	[1]
Forfeited, Weighted Average Exercise Price per Share | $ / shares	6.01	[1]
Weighted Average Exercise Price per Share, Ending Balance | $ / shares	$ 5.83

[1] Includes shares issuable under performance-based restricted stock unit awards.