Net Income Per Share - (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net income per share:
Net income attributable to SMTP.com	$ 319,587	$ 313,854	$ 930,593	$ 758,910
Basic weighted average common shares outstanding	15,130,162	14,707,250	14,931,366	14,297,562
Add incremental shares for:
Warrants	2,626,450		53,228
Stock options	543,352	551,593	554,058	598,986
Diluted weighted average common shares outstanding	15,699,964	15,258,843	15,538,652	14,896,548
Net income per share:
Basic	$ 0.02	$ 0.02	$ 0.06	$ 0.05
Diluted	$ 0.02	$ 0.02	$ 0.06	$ 0.05