Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Series A Convertible Preferred Stock
Shares issued, price per share			$ 1.00	$ 1.00
Convertible preferred stock, Issuance costs			$ 5	$ 7
Series B Convertible Preferred Stock
Shares issued, price per share		$ 2.00
Convertible preferred stock, Issuance costs	$ 34	$ 239