Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' (Deficit) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2019	Jun. 30, 2018	Mar. 31, 2018
Statement Of Stockholders Equity [Abstract]
Issuance of redeemable convertible preferred stock, net of issuance costs			$ 2,243
Issuance of common stock upon IPO, net of issuance costs	$ 525	$ 10,487