Organization and Description of Business - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
	Jul. 31, 2020	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Organization and Description of Business [Line Item]
Accumulated deficit		$ 205,205		$ 162,158
Cash and cash equivalents		53,025		$ 74,025
Working capital		45,900
Proceeds from issuance of common stock		472	$ 46,308
Aggregate offering price		200,000
SFJ Pharmaceuticals X, Ltd.
Organization and Description of Business [Line Item]
Proceeds from partnership contribution		71,600
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
Subsequent Event
Organization and Description of Business [Line Item]
Proceeds from issuance of common stock	$ 2,400
Aggregate offering price	197,100
Subsequent Event | 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	$ 57,100