Basic and Diluted Net 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
Earnings Per Share [Abstract]
Net loss		$ (418,780)	$ (554,128)	$ (715,075)
Weighted-average common shares outstanding - basic		81,262	77,956	73,615
Effect of dilutive securities*	[1]	0	0	0
Weighted-average common shares outstanding - diluted		81,262	77,956	73,615
Net loss per share — basic and diluted		$ (5.15)	$ (7.11)	$ (9.71)

[1] For the years ended December 31, 2021, 2020 and 2019, stock options, RSAs, RSUs and ESPP to purchase approximately 9.7 million, 9.0 million and 9.1 million shares of common stock, respectively, were excluded from the net loss per share calculation as their effect would have been anti-dilutive. The Company accounts for the effect of the 2024 Notes on diluted net earnings per share using the if-converted method as this obligation may be settled in cash or shares at the Company’s option. The effect of potential share settlement is included in the diluted net earnings per share calculation if the effect is more dilutive. During the year ended December 31, 2021, the inclusion of the potential share settlement of the 2024 Notes was anti-dilutive. Accordingly, the potential conversion of 7,763,552 shares has been excluded from the computation of diluted net earnings per share as of December 31, 2021.