Quarterly Financial Data (Unaudited) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 9,395,300	$ 9,683,226	$ 9,552,589	$ 19,939,876	$ 11,793,909	$ 11,175,440	$ 11,302,667	$ 12,001,499	$ 48,570,991	$ 46,273,515	$ 58,636,504
Gross profit	7,208,145	7,257,275	6,893,803	17,529,634	9,137,575	8,583,096	8,595,004	9,327,124	38,888,857	35,642,799	43,480,690
Net (loss) income attributable to common stockholders	$ (2,295,014)	$ (2,922,694)	$ (2,998,645)	$ 4,934,176	$ (2,827,016)	$ (3,545,218)	$ 1,023,512	$ (3,104,078)	$ (1,929,361)	$ (7,211,821)	$ (10,932,590)
Basic net (loss) income per share attributable to common stockholders (in dollars per share)	$ (0.06)	$ (0.07)	$ (0.07)	$ 0.12	$ (0.06)	$ (0.08)	$ 0.02	$ (0.06)	$ (0.08)	$ (0.18)	$ (0.24)
Diluted net (loss) income per share attributable to common stockholders (in dollars per share)	$ (0.06)	$ (0.07)	$ (0.07)	$ 0.10	$ (0.06)	$ (0.08)	$ 0.02	$ (0.06)	$ (0.08)	$ (0.18)	$ (0.24)