Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' (Deficit) Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Issuance of redeemable convertible preferred stock, net of issuance costs	$ 2,243	$ 85
Issuance of common stock upon IPO, net of issuance costs	$ 2,628