Quarterly Data - Schedule of Quarterly Financial Information (Unaudited) (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 21,185	$ 18,923	$ 19,842	$ 17,506	$ 22,898	$ 23,630	$ 23,499	$ 20,590	$ 77,456	$ 90,617
Gross profit	10,616	9,575	9,521	8,215	11,513	10,647	10,694	8,658	37,927	41,512
Operating income (loss)	1,985	1,135	1,098	(878)	1,707	941	629	(469)	3,340	2,808
Income (loss) before income taxes	1,875	1,051	1,200	(680)	1,814	1,334	949	(307)	3,446	3,790
Net income (loss)	$ 1,871	$ 1,042	$ 1,192	$ (688)	$ 1,798	$ 1,328	$ 941	$ (317)	$ 3,417	$ 3,750
Net income (loss) per share:
Basic	$ 0.10	$ 0.06	$ 0.07	$ (0.04)	$ 0.10	$ 0.07	$ 0.05	$ (0.02)	$ 0.19	$ 0.21
Diluted	$ 0.10	$ 0.06	$ 0.07	$ (0.04)	$ 0.10	$ 0.07	$ 0.05	$ (0.02)	$ 0.19	$ 0.21
Weighted Average Shares:
Basic	18,149,356	18,198,567	18,159,029	18,207,165	18,033,548	17,921,552	17,827,591	17,617,099	18,207,396	17,852,968
Diluted	18,297,058	18,310,772	18,213,617	18,207,165	18,460,503	18,181,157	17,934,141	17,617,099	18,398,788	18,158,659