Subsequent Events - Public Offering of Common Stock (Details) - USD ($)			12 Months Ended
	Feb. 05, 2019	Mar. 27, 2018	Dec. 31, 2018	Dec. 31, 2017
Subsequent Events
Proceeds from the issuance of common stock				$ 10,000,000
Warrant Liability | Subsequent Events
Subsequent Events
Exercise price of warrant	$ 1.95
Warrant expiring period	7 years
Public Offering | Subsequent Events
Subsequent Events
Number of warrants issued per common stock	1
Public Offering | Common Stock
Subsequent Events
Issuance of stock (in shares)		2,146,667	2,146,667
Price per common stock (in dollars per share)		$ 7.50
Proceeds from the issuance of common stock		$ 14,796,000.000
Public Offering | Common Stock | Subsequent Events
Subsequent Events
Issuance of stock (in shares)	7,557,142
Price per common stock (in dollars per share)	$ 1.75
Proceeds from the issuance of common stock	$ 12,081,000
Public Offering | Warrant Liability | Subsequent Events
Subsequent Events
Exercise price of warrant	$ 1.75
Over-Allotment Option | Common Stock
Subsequent Events
Issuance of stock (in shares)	985,714	280,000
Over-Allotment Option | Common Stock | Subsequent Events
Subsequent Events
Issuance of stock (in shares)	985,714