Related Party Transactions - Additional Information (Details) - USD ($)		3 Months Ended		9 Months Ended
	May 05, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Commercial Supply Agreement
Related Party Transaction [Line Items]
Agreement extends period for termination	2 years
Minimum purchase obligation	$ 2,400,000
Drug Product | Commercial Supply Agreement
Related Party Transaction [Line Items]
Outstanding accounts payable and accrued expenses		$ 100,000		$ 100,000
Expense related to services		100,000		100,000
Frazier
Related Party Transaction [Line Items]
Outstanding accounts payable and accrued expenses		35,000		35,000		$ 100,000
Shared operating expenses		62,000	$ 200,000	100,000	$ 300,000
PCI Pharma Services | Clinical Manufacturing Services
Related Party Transaction [Line Items]
Outstanding accounts payable and accrued expenses		600,000		600,000		300,000
Expense related to services		900,000	200,000	1,500,000	200,000
Mountain Field LLC
Related Party Transaction [Line Items]
Shared operating expenses		0	0	0	100,000
Takeda | Takeda License
Related Party Transaction [Line Items]
Outstanding accounts payable and accrued expenses		22,000		22,000		$ 100,000
Expense related to services		$ 0	$ 0	$ 0	$ 0