Stockholder's Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended	6 Months Ended
	Apr. 17, 2020	Aug. 13, 2019	Mar. 31, 2020	Jun. 30, 2020	Dec. 31, 2019	Jul. 31, 2018
Subsidiary Sale Of Stock [Line Items]
Common stock, shares authorized				200,000,000	200,000,000
Common stock and paid-in capital, par value				$ 0.001	$ 0.001
Preferred stock, shares authorized				10,000,000	10,000,000
Preferred stock, par value				$ 0.001	$ 0.001
Proceeds from issuance of common stock, net		$ 75,000		$ 6,427
Maximum amount of common stock preferred stock debt securities warrants and units to be issued		300,000
Registration Statement effective date				Aug. 29, 2019
Common stock, shares issued				32,906,000	24,296,000
SVB Leerink LLC and Cantor Fitzgerald & Co. | Maximum [Member]
Subsidiary Sale Of Stock [Line Items]
Sale of common stock at offering price		$ 75,000
Common Stock
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock, shares				276,000
Initial Public Offering
Subsidiary Sale Of Stock [Line Items]
Common stock, shares authorized						200,000,000
Common stock and paid-in capital, par value						$ 0.001
Preferred stock, shares authorized						10,000,000
Preferred stock, par value						$ 0.001
Proceeds from issuance of common stock, net	$ 107,900
Offering Discounts Commissions And Offering Costs Net	$ 7,300
Initial Public Offering | Common Stock
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock, shares	8,222,500
Common stock price per share	$ 14.00
ATM Offering
Subsidiary Sale Of Stock [Line Items]
Proceeds from issuance of common stock, net			$ 6,400
Common stock, shares issued			275,764	0