Related Party Transactions - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Outstanding accounts payable	$ 57,000		$ 57,000		$ 45,000
Frazier
Related Party Transaction [Line Items]
Outstanding accounts payable	71,000		71,000		45,000
Shared operating expenses	200,000	$ 66,000	300,000	$ 200,000
PCI Pharma Services | Clinical Manufacturing Services
Related Party Transaction [Line Items]
Prepaid services	100,000		100,000
Outstanding accounts payable and accrued expenses	200,000		200,000
Expense related to services	200,000		200,000
Mountain Field LLC
Related Party Transaction [Line Items]
Outstanding accounts receivable	0		0		$ 19,000
Shared operating expenses	$ 0	$ 5,000	$ 100,000	$ 2,000