Condensed Consolidated Statements of Stockholders' Equity (Deficit) (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
January 2019 Public Offering
Stock offering transaction cost	$ 739
May 2019 Public Offering
Stock offering transaction cost	$ 1,683
2018 Public Offering
Stock offering transaction cost		$ 2,096
Over-Allotment Option
Overallotment related to transaction cost		$ 10