Organization and Description of Business - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Organization and Description of Business [Line Item]
Accumulated deficit	$ 230,348	$ 162,158
Cash and cash equivalents	39,353	$ 74,025
Working capital	38,600
Aggregate offering price	200,000
Aggregate offering price, remaining	197,100
SFJ Pharmaceuticals X, Ltd.
Organization and Description of Business [Line Item]
Proceeds from partnership contribution	58,300
Equity Distribution Agreement with Citigroup Global Markets Inc. and William Blair & Company, L.L.C.
Organization and Description of Business [Line Item]
Aggregate offering price	60,000
Aggregate offering price, remaining	$ 57,100