Selected Quarterly Financial Data (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information [Line Items]
Revenues	$ 6,762,000	$ 7,704,000	$ 7,694,000	$ 7,045,000	$ 6,484,000	$ 7,055,000	$ 6,899,000	$ 6,432,000
Gross profit	3,482,000	3,970,000	3,891,000	3,796,000	3,652,000	4,176,000	4,079,000	3,487,000	15,138,166	15,394,034	14,251,648
Income from operations	958,000	1,244,000	1,320,000	1,168,000	1,033,000	1,739,000	1,732,000	1,202,000	4,689,641	5,706,365	4,935,688
Net income and comprehensive income	$ 676,000	$ 917,000	$ 857,000	$ 756,000	$ 868,000	$ 1,052,000	$ 1,063,000	$ 822,000	$ 3,206,081	$ 3,805,210	$ 2,979,629
Basic net income per share (in dollars per share)	$ 0.13	$ 0.17	$ 0.16	$ 0.14	$ 0.16	$ 0.20	$ 0.20	$ 0.16	$ 0.60	$ 0.72	$ 0.57
Diluted net income per share (in dollars per share)	$ 0.13	$ 0.17	$ 0.16	$ 0.14	$ 0.16	$ 0.20	$ 0.20	$ 0.16	$ 0.60	$ 0.72	$ 0.57