Quarterly Financial Information (Unaudited) - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Selected Quarterly Financial Information [Line Items]
Gain (loss) on change in the fair value of the derivative liability		$ (20,200)
Impairment charge	$ 16,300				$ 19,200		$ 3,527
Other gains and (losses), net					$ (10,889)	$ 23,400	2,332
Loss on call spread modification related to convertible notes				$ 5,000		$ 5,417	$ 4,869
Aurora [Member]
Selected Quarterly Financial Information [Line Items]
Other gains and (losses), net	$ 6,900
Peterson Companies [Member]
Selected Quarterly Financial Information [Line Items]
Other gains and (losses), net			$ 26,100
Term of Peterson Note						3 years