Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2017	[1]	Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	[2]	Dec. 31, 2016	[2]	Dec. 31, 2015
Revenues	$ 24,613		$ 24,706		$ 52,231		$ 38,830		$ 7,779	$ 34,930	$ 34,605	$ 28,167	$ 140,380		$ 105,481		$ 79,722
Gross profit	3,027		5,070		17,420		12,467		1,033	12,040	10,491	7,522	37,984		31,086		18,489
Operating expenses	12,664		3,594		3,520		3,074		3,267	4,022	2,347	2,503	22,852		12,139		10,308
Operating income (loss)	(9,637)		1,476		13,900		9,393		(2,234)	8,018	8,144	5,019	15,132		18,947		8,181
Other (expense)	(2,958)		(24)		(61)		(85)		(763)	(296)	(352)	(271)	(3,128)		(1,682)		(474)
Income (loss) before income taxes	(12,595)		1,452		13,839		9,308		(2,997)	7,722	7,792	4,748	12,004		17,265		7,707
Income tax expense (benefit)	(7,389)		(652)		5,314		3,574		(1,071)	2,933	2,962	1,804	847		6,628		2,944
Net income (loss)	$ (5,206)		$ 2,104		$ 8,525		$ 5,734		$ (1,926)	$ 4,789	$ 4,830	$ 2,944	$ 11,157		$ 10,637		$ 4,763
Net income (loss) per common share - Basic	$ (0.12)	[2]	$ 0.05	[2]	$ 0.21	[2]	$ 0.14	[2]	$ (0.05)	$ 0.14	$ 0.15	$ 0.09	$ 0.27		$ 0.31		$ 0.15
Net income (loss) per common share - Diluted	$ (0.12)	[2]	$ 0.05	[2]	$ 0.20	[2]	$ 0.13	[2]	$ (0.05)	$ 0.14	$ 0.14	$ 0.09	$ 0.26		$ 0.3		$ 0.14
Weighted average number of shares outstanding - Basic	42,216,987		41,869,528		41,567,848		41,507,941		36,527,250	33,873,479	33,128,518	32,888,659	41,764,230		34,104,476		32,546,840
Weighted average number of shares outstanding - Diluted	42,216,987		43,463,982		43,550,226		43,503,889		36,527,250	35,297,585	34,270,337	33,944,876	42,766,843		35,416,910		33,936,099

[1] As discussed previously, the fourth quarter 2017 results include the results of ARI subsequent to the acquisition on October 10, 2017.

[2] 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.