CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - Common Stock - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Public Offering
Share Price (in dollars per share)	$ 1.25	$ 3.75
Stock issuance costs	$ 2,786	$ 2,853
2017 Equity Distribution Agreement
Stock issuance costs	$ 95