Basic and Diluted Net (Loss) Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Net (loss) income		$ (109,267)	$ (63,046)	$ (144,630)	$ 21,044
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) earnings per share		65,484	54,976	65,060	54,913
Dilutive effect of outstanding stock awards and stock options after application of the treasury stock method	[1]	0	0	0	1,263
Weighted-average number of shares of common stock and dilutive common stock equivalents outstanding for computing diluted loss per share		65,484	54,976	65,060	56,176
Net (loss) earnings per share - basic and diluted
Basic (loss) earnings per share		$ (1.67)	$ (1.15)	$ (2.22)	$ 0.38
Diluted (loss) earnings per share		$ (1.67)	$ (1.15)	$ (2.22)	$ 0.37

[1] For the three and six months ended June 30, 2018, stock options, RSAs, RSUs, stock appreciation rights (“SAR”) to purchase 9.4 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 months ended June 30, 2017, stock options, RSAs and SARs to purchase 10.1 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 six months ended June 30, 2017, out of money stock options, unvested performance-based RSUs and RSAs whose performance milestones were not achieved and potentially issuable common stock for ESPP to purchase approximately 7.0 million shares of the Company’s common stock were excluded from the net earnings per share calculation as their effect would have been anti-dilutive.