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, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Net loss		$ (47,734)	$ (56,742)	$ (26,690)	$ (178,813)
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		61,528	48,254	57,166	46,709
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		61,528	48,254	57,166	46,709
Net loss per share - basic and diluted		$ (0.78)	$ (1.18)	$ (0.47)	$ (3.83)

[1] For the three and nine months ended September 30, 2017, stock options, RSAs, RSUs and stock appreciation rights (“SARs”) to purchase 9.8 million shares of the Company’s common stock were excluded from the net loss per share calculation as their effect would have been anti-dilutive.  For the three and nine months ended September 30, 2016, stock options, RSAs and SARs to purchase 6.3 million shares of the Company’s common stock were excluded from the net loss per share calculation as their effect would have been anti-dilutive.