Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 610,000	$ 494,000
Accumulated amortization	$ 5,874,000	$ 5,380,000
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	3,000,000	3,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	26,768,914	25,219,805
Common stock, shares outstanding	26,768,914	25,219,805