Warrants, Outstanding Common Stock Warrants (Details)	9 Months Ended
	Sep. 30, 2018 $ / shares shares
Warrants and Rights [Abstract]
Total Warrants (in shares) | shares	2,392,760
Expiration Date, April 30, 2019 [Member]
Warrants and Rights [Abstract]
Issue Date	Oct. 31, 2013	[1]
Expiration Date	Apr. 30, 2019	[1]
Total Warrants (in shares) | shares	137,143	[1]
Exercise price (in dollars per share) | $ / shares	$ 3.75	[1]
Expiration Date, February 5, 2019 [Member]
Warrants and Rights [Abstract]
Issue Date	Feb. 05, 2014	[1]
Expiration Date	Feb. 05, 2019	[1]
Total Warrants (in shares) | shares	265,947	[1]
Exercise price (in dollars per share) | $ / shares	$ 3.75	[1]
Expiration Date, July 24, 2019 [Member]
Warrants and Rights [Abstract]
Issue Date	Jul. 24, 2014
Expiration Date	Jul. 24, 2019
Total Warrants (in shares) | shares	1,239,769
Expiration Date, July 24, 2019 [Member] | Minimum [Member]
Warrants and Rights [Abstract]
Exercise price (in dollars per share) | $ / shares	$ 3.75
Expiration Date, July 24, 2019 [Member] | Maximum [Member]
Warrants and Rights [Abstract]
Exercise price (in dollars per share) | $ / shares	$ 12.25
Expiration Date, June 22, 2020 [Member]
Warrants and Rights [Abstract]
Issue Date	Jun. 22, 2015
Expiration Date	Jun. 22, 2020
Total Warrants (in shares) | shares	600,000
Exercise price (in dollars per share) | $ / shares	$ 3.75
Expiration Date, December 30, 2020 [Member]
Warrants and Rights [Abstract]
Issue Date	Dec. 30, 2015
Expiration Date	Dec. 30, 2020
Total Warrants (in shares) | shares	130,089
Exercise price (in dollars per share) | $ / shares	$ 5.65
Expiration Date, January 29, 2021 [Member]
Warrants and Rights [Abstract]
Issue Date	Jan. 29, 2016
Expiration Date	Jan. 29, 2021
Total Warrants (in shares) | shares	19,812
Exercise price (in dollars per share) | $ / shares	$ 5.30

[1] These warrants are classified as liabilities.