Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net loss		$ (51,939)	$ (29,226)	$ (155,349)	$ (91,373)
Weighted-average number of shares of common stock and common stock equivalents outstanding:
Weighted-average number of shares of common stock outstanding for computing basic loss per share		41,565	41,066	41,416	39,595
Dilutive effect of outstanding stock awards and stock options after application of the treasury stock method	[1]
Weighted-average number of shares of common stock and dilutive common stock equivalents outstanding for computing diluted loss per share		41,565	41,066	41,416	39,595
Net loss per share — basic and diluted		$ (1.25)	$ (0.71)	$ (3.75)	$ (2.31)

[1] For the three and nine months ended September 30, 2015 and 2014, stock options, RSAs and stock appreciation rights to purchase approximately 7.3 million and 5.3 million shares of common stock, respectively, were excluded from the net loss per share calculation as their effect would have been anti-dilutive.