Warrants (Tables)

3 Months Ended

Mar. 31, 2019

Warrants [Abstract]

Outstanding Common Stock Warrants

Outstanding common stock warrants at March 31, 2019, consist of the following:

Issue Date	Expiration Date	Total Warrants		Exercise Price
October 31, 2013*	4/30/2019		137,143	$	3.75
July 24, 2014	7/24/2019		1,239,769	$	3.75 - $ 12.25
June 22, 2015	6/22/2020		600,000	$	3.75
December 30, 2015	12/30/2020		130,089	$	5.65
January 29, 2016	1/29/2021		19,812	$	5.30
			2,126,813

*These warrants are classified as liabilities.