Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Convertible preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized	64,871,795	44,867,089
Convertible preferred stock, shares issued	64,839,353	33,668,075
Convertible preferred stock, shares outstanding	64,839,353	33,668,075
Convertible preferred stock, liquidation preference	$ 194,727	$ 65,002
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	80,000,000	57,803,522
Common stock, shares issued	2,236,672	2,173,684
Common stock, shares outstanding	2,236,672	2,173,684