Inventories (Detail) - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Raw material		$ 1,044	$ 819
Work-in-process		8,273	8,142
Finished goods	[1]	8,145	33,784
Supplies		468	1,431
Total inventories		17,930	44,176
Inventory fair value adjustments		$ 0	$ 30,400

[1] The amount shown above includes the unamortized fair value adjustment of $0.0 million and $30.4 million at June 30, 2016 and December 31, 2015, respectively.