Stockholders' Equity - Capital Structure (Details)			1 Months Ended				3 Months Ended	9 Months Ended
	Jan. 31, 2019 USD ($) shares	Sep. 27, 2018 USD ($) $ / shares shares	May 31, 2019 USD ($)	Dec. 31, 2017 USD ($) $ / shares shares	Oct. 31, 2017 USD ($)	Mar. 31, 2017 USD ($) $ / shares shares	Sep. 30, 2019 USD ($) shares	Sep. 30, 2019 Vote / shares shares	Sep. 30, 2018 USD ($) $ / shares	Dec. 01, 2016 USD ($)
Subsidiary, Sale of Stock [Line Items]
Shelf Registration Statement, maximum aggregate amount issuable										$ 150,000,000
Remaining shares available for sale, shelf registration statement | shares							57,400,000	57,400,000
Shares issued | shares	3,164,015	2,966,667		1,783,587		4,304,813	942,285
Share Price | $ / shares		$ 3.00		$ 5.325		$ 3.74
Proceeds from issuance of common stock, gross		$ 8,900,000		$ 9,500,000		$ 16,100,000	$ 20,100,000
Proceeds from issuance of common stock, net		8,800,000		8,800,000		$ 14,800,000	$ 19,500,000
Common stock sales agreement, authorized amount		$ 2,966,667	$ 50,000,000		$ 30,000,000
Common stock sales agreement, gross sales	$ 25,800,000
Common stock sales agreement, commission percentage	3.00%		3.00%
Issuance costs				$ 745,856
Exercise price | $ / shares				$ 5.25
Common stock, voting right per share | Vote / shares								1
Common warrants
Subsidiary, Sale of Stock [Line Items]
Share Price | $ / shares				$ 5.60					$ 3.45
Issuance costs				$ 583,768
Exercise price | $ / shares				$ 5.25
Warrant utilized				$ 9,400,000
Fair Value Of Warrants				$ 2,683,000					$ 101,000
Placement agent warrants
Subsidiary, Sale of Stock [Line Items]
Shares issued | shares				107,015
Share Price | $ / shares				$ 5.60					$ 3.45
Issuance costs				$ 81,000
Exercise price | $ / shares				$ 6.6562
Warrant utilized				$ 712,313
Fair Value Of Warrants				$ 108,000					$ 1,000