Consolidated Statements of Convertible Preferred Stock and Stockholders' (Deficit) Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Private Placement
Offering cost			$ 111
Direct Registered Offering
Offering cost		$ 177	81
Public Offering
Offering cost	$ 11,146	10,631
At The Market Offering Program
Offering cost		$ 6	$ 1,147