Quarterly Financial Data (Unaudited) (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues	$ 7,779		$ 34,930		$ 34,605		$ 28,167		$ 7,300	$ 21,682	$ 28,637	$ 22,103	$ 105,481	$ 79,722	$ 55,810
Gross profit	1,033		12,040		10,491		7,522		1,368	4,384	7,212	5,525	31,086	18,489	6,446
Operating expenses	3,267		4,022		2,347		2,503		3,120	2,482	2,451	2,255	12,139	10,308	7,431
Operating income (loss)	(2,234)		8,018		8,144		5,019		(1,752)	1,902	4,761	3,270	18,947	8,181	(985)
Other Income (expense)	(763)		(296)		(352)		(271)		126	(157)	(236)	(207)	(1,682)	(474)	(641)
Income (loss) before income taxes	(2,997)		7,722		7,792		4,748		(1,626)	1,745	4,525	3,063	17,265	7,707	(1,626)
Income tax expense (benefit)	(1,071)		2,933		2,962		1,804		(603)	663	1,714	1,170	6,628	2,944	(906)
Net income (loss)	$ (1,926)		$ 4,789		$ 4,830		$ 2,944		$ (1,023)	$ 1,082	$ 2,811	$ 1,893	$ 10,637	$ 4,763	$ (720)
Net income (loss) per common share - Basic	$ (0.05)	[1]	$ 0.14	[1]	$ 0.15	[1]	$ 0.09	[1]	$ (0.03)	$ 0.03	$ 0.09	$ 0.06	$ 0.31	$ 0.15	$ (0.02)
Net income (loss) per common share - Diluted	$ (0.05)	[1]	$ 0.14	[1]	$ 0.14	[1]	$ 0.09	[1]	$ (0.03)	$ 0.03	$ 0.08	$ 0.06	$ 0.3	$ 0.14	$ (0.02)
Weighted average number of shares outstanding - Basic	36,527,250		33,873,479		33,128,518		32,888,659		32,715,802	32,639,429	32,542,672	32,333,443	34,104,476	32,546,840	29,122,746
Weighted average number of shares outstanding - Diluted	36,527,250		35,297,585		34,270,337		33,944,876		32,715,802	33,856,045	34,383,092	34,280,385	35,416,910	33,936,099	29,122,746

[1] The sum of the net earnings per share may not add up to the full year amount due to rounding and because the quarterly calculations are based on varying numbers of shares outstanding.