Selected Quarterly Results (Unaudited) - Selected Quarterly Results (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Selected Quarterly Financial Information [Abstract]
Revenue	$ 32,209	$ 1,235	$ 1,733	$ 13,054	$ 2,547	$ 1,822	$ 13,885	$ 20,690	$ 48,231	$ 38,944	$ 11,356
Gross profit	29,552	(464)	(888)	11,930	(516)	1,359	13,198	19,964
Income (loss) from operations	10,953	(19,652)	(18,681)	(7,800)	(18,353)	(19,059)	(2,041)	713	(35,179)	(38,740)	(56,402)
Net (loss ) income	$ 10,171	$ (20,439)	$ (19,211)	$ (8,193)	$ (17,647)	$ (25,256)	$ (6,671)	$ (4,644)	$ (37,672)	$ (54,218)	$ (57,394)
Basic (loss) income per share	$ 0.20	$ (0.39)	$ (0.37)	$ (0.16)	$ (0.36)	$ (0.51)	$ (0.14)	$ (0.11)
Diluted (loss) income per share	$ 0.20	$ (0.39)	$ (0.37)	$ (0.16)	$ (0.36)	$ (0.51)	$ (0.14)	$ (0.11)