Organization and Nature of Operations - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Oct. 01, 2018	Dec. 31, 2019	Dec. 31, 2018	Jul. 14, 2018	Jul. 13, 2018
Subsidiary Sale Of Stock [Line Items]
Common stock, par value		$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares authorized		300,000,000	300,000,000	25,000,000	10,000,000
Proceeds from issuance of common stock		$ 37	$ 78,806
Offering costs			$ 3,556
Preferred stock, par value		$ 0.0001	$ 0.0001
Preferred stock, shares authorized		10,000,000	10,000,000
Accumulated deficit		$ 117,157	$ 60,221
Net cash used in operating activities		33,173	$ 18,508
Cash equivalents and short-term investments		$ 30,600
IPO [Member]
Subsidiary Sale Of Stock [Line Items]
Common stock issued, shares	4,485,000
Common stock, offering price per share	$ 17.00
Gross proceeds from issuance of IPO	$ 76,200
Proceeds from issuance of common stock	67,300
Underwriting discount	5,300
Offering costs	$ 3,600
Over-Allotment Option [Member]
Subsidiary Sale Of Stock [Line Items]
Common stock issued, shares	585,000