Quarterly Results (Unaudited) (Details) - 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
Quarterly financial data
Revenue, net	$ 47,074	$ 42,467	$ 38,510	$ 33,569	$ 39,183	$ 35,137	$ 35,291	$ 31,233	$ 161,620	$ 140,844	$ 138,302
Operating expenses:
Cost of revenue	26,746	26,675	25,605	23,026	23,855	22,367	23,431	21,646	102,052	91,299	93,169
Selling, general and administrative expenses	12,792	12,189	11,424	10,536	11,048	9,883	9,620	8,848	46,941	39,399	32,284
Depreciation of property and equipment	1,107	1,133	1,109	1,220	1,209	1,376	1,216	1,232	4,569	5,033	5,317
Amortization of intangible assets	1,468	722	722	722	650	393	395	394	3,634	1,832	2,458
Acquisition-related adjustments	(2,283)	0	0	0	0	0	0	0	(2,283)	0	0
Total operating expenses	39,830	40,719	38,860	35,504	36,762	34,019	34,662	32,120	154,913	137,563	133,228
Operating income from continuing operations	7,244	1,748	(350)	(1,935)	2,421	1,118	629	(887)	6,707	3,281	5,074
Foreign currency transaction (gains) losses on short-term intercompany balances	(263)	(418)	(957)	(552)	1,060	(165)	196	(1,007)	(2,190)	84	2,165
Interest expense (income), net	1,312	142	48	37	(98)	(14)	(12)	(29)	1,539	(153)	(190)
Other (income) loss	17	17	5	(199)	19	(168)	18	10	(160)	(121)	1,191
Net income from continuing operations before income tax	6,178	2,007	554	(1,221)	1,440	1,465	427	139	7,518	3,471	1,908
Income tax expense (benefit)	526	930	879	627	1,263	(685)	460	204	2,962	1,242	369
Net income from continuing operations	$ 5,652	$ 1,077	$ (325)	$ (1,848)	$ 177	$ 2,150	$ (33)	$ (65)	$ 3,184	$ 905	$ (3,226)
Basic (loss) earnings per common share from continuing operations (usd per share)	$ 0.26	$ 0.05	$ (0.01)	$ (0.08)	$ 0.01	$ 0.10	$ 0.00	$ 0.00	$ 0.15	$ 0.04	$ (0.12)
Diluted (loss) earnings per common share from continuing operations (usd per share)	$ 0.26	$ 0.05	$ (0.01)	$ (0.08)	$ 0.01	$ 0.10	$ 0.00	$ 0.00	$ 0.15	$ 0.04	$ (0.12)