Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Series A Convertible Preferred Stock
Issuance of shares, offering costs	$ 0.4
Series B Convertible Preferred Stock
Issuance of shares, offering costs	$ 0.5