Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Jan. 09, 2018	Dec. 31, 2018	Dec. 31, 2017
Class of Warrant or Right [Line Items]
Common stock issued through public offering (in shares)	10,000,000
Public offering price per share (in USD per share)	$ 3.8
Warrant exercise price (in USD per share)	$ 4.66
Warrants expiration period	4 years
Warrant exercise limitation, maximum beneficial ownership percentage, current	4.99%
Warrant exercise limitation, maximum beneficial ownership percentage, if elected by holder	9.99%
Beneficial ownership percentage, exception to exercise limitation provision	10.00%
Fundamental transaction common stock acquired threshold	50.00%
Maximum volatility rate used to derive Black-Scholes Value in event of fundamental transaction	100.00%
Warrants exercised (in shares)		0
Change in fair value of warrant liability		$ 16,566	$ 0
Other income and expense
Class of Warrant or Right [Line Items]
Change in fair value of warrant liability		$ 16,566
Warrant liability
Class of Warrant or Right [Line Items]
Warrant fair value per share (in USD per share)	$ 1.78	$ 0.12
Maximum
Class of Warrant or Right [Line Items]
Warrants issued (in shares)	10,000,000