Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
	Apr. 17, 2019	Mar. 31, 2019	Dec. 31, 2018	Oct. 09, 2018
Common Stock
Subsequent Event [Line Items]
Shares agreed to sell upon agreement		206,000	1,277,000
Securities Purchase Agreement
Subsequent Event [Line Items]
Purchase price per share				$ 2.35
Conversion of preferred stock to common stock				866,950
Securities Purchase Agreement | Series C Convertible Preferred Stock | Thomas B. Pickens III | Subsequent Events
Subsequent Event [Line Items]
Shares agreed to sell upon agreement	280,898
Preferred stock, par value	$ 0.001
Securities Purchase Agreement | Series D Convertible Preferred Stock | Thomas B. Pickens III | Subsequent Events
Subsequent Event [Line Items]
Shares agreed to sell upon agreement	280,898
Preferred stock, par value	$ 0.001
Securities Purchase Agreement | Common Stock | Subsequent Events | Maximum [Member]
Subsequent Event [Line Items]
Preferred shares conversion percentage to common shares	9.99%
Securities Purchase Agreement | Common Stock | Thomas B. Pickens III | Subsequent Events
Subsequent Event [Line Items]
Aggregate gross proceeds from agreement on sale of shares	$ 2.0
Purchase price per share	$ 3.56
Securities Purchase Agreement | Common Stock | Series D Convertible Preferred Stock | Subsequent Events
Subsequent Event [Line Items]
Conversion of preferred stock to common stock	280,898