Summary of Significant Accounting Policies (Details) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Potentially dilute securities excluded from calculation	395,348	407,390
Convertible preferred stock [Member]
Potentially dilute securities excluded from calculation	688	688
Warrants to purchase common stock [Member]
Potentially dilute securities excluded from calculation	285,273	294,072
Options to purchase common stock [Member]
Potentially dilute securities excluded from calculation	109,387	112,630