Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Net loss		$ (62,301)	$ (41,851)	$ (122,071)	$ (103,410)
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		46,157	41,357	45,927	41,341
Dilutive effect of outstanding stock awards and stock options after application of the treasury stock method	[1]	0	0	0	0
Weighted-average number of shares of common stock and dilutive common stock equivalents outstanding for computing diluted loss per share		46,157	41,357	45,927	41,341
Net loss per share — basic and diluted		$ (1.35)	$ (1.01)	$ (2.66)	$ (2.50)

[1] For the three and six months ended June 30, 2016 and 2015, stock options, RSAs and stock appreciation rights to purchase approximately 7.3 million and 7.0 million shares of common stock, respectively, were excluded from the net loss per share calculation as their effect would have been anti-dilutive.