CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY
Equity Distribution Agreement, expenses	$ 380
Share Price (in dollars per share)	$ 3.75	$ 6
Stock issuance costs	$ 2,555	$ 2,200