Selected Quarterly Financial Data (unaudited) - Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Total revenues	$ 114,890	$ 50,894	$ 38,267	$ 73,692	$ 52,808	$ 49,341	$ 39,133	$ 50,321	$ 277,743	$ 191,603	$ 196,129
Cost of sales									121,601	79,872	78,029
Gross profit	59,127	29,690	18,826	48,499	32,001	30,023	20,225	29,482	156,142	111,731	118,100
Operating Income (Loss)	3,887	(2,537)	(11,027)	19,229	5,915	2,125	(9,019)	(3,460)	9,552	(4,439)	2,738
Net loss	$ (5,088)	$ (5,525)	$ (11,842)	$ 14,290	$ (1,950)	$ (572)	$ (7,840)	$ (3,446)	$ (8,165)	$ (13,808)	$ (6,079)
Basic and diluted loss per share	$ (0.15)	$ (0.16)	$ (0.35)	$ 0.43	$ (0.06)	$ (0.02)	$ (0.24)	$ (0.11)
Diluted net earnings (loss) per share	$ (0.15)	$ (0.16)	$ (0.35)	$ 0.42