Quarterly Financial Information (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Summary of Statements of Operations
Revenue	$ 25,856	$ 25,485	$ 24,505	$ 25,548	$ 23,384	$ 24,029	$ 23,422	$ 26,008	$ 101,394	$ 96,843
Gross profit	5,025	4,842	4,390	4,802	4,288	4,804	5,107	5,250	19,059	19,449
Income (loss) from operations	611	1,115	(270)	(277)	(992)	(478)	14	405	1,179	(1,051)
Net income (loss)	$ 696	$ 610	$ (202)	$ (188)	$ (502)	$ (166)	$ 21	$ 184	$ 916	$ (463)
Basic income (loss) per share	$ 0.06	$ 0.06	$ (0.02)	$ (0.02)	$ (0.05)	$ (0.02)	$ 0.00	$ 0.02	$ 0.08	$ (0.04)
Diluted income (loss) per share	$ 0.06	$ 0.05	$ (0.02)	$ (0.02)	$ (0.05)	$ (0.02)	$ 0.00	$ 0.02	$ 0.08	$ (0.04)
Shares used in calculation of income (loss) per share:
Basic	11,058	10,943	10,922	10,875	10,703	10,610	10,563	10,430	10,945	10,594
Diluted	11,310	11,474	10,922	10,875	10,703	10,610	10,529	11,704	11,449	10,594