Subsequent Events - Additional Information (Details) - Securities Purchase Agreement - Subsequent Events $ / shares in Units, $ in Millions	Oct. 09, 2018 USD ($) $ / shares shares
Subsequent Event [Line Items]
Aggregate gross proceeds from agreement on sale of shares | $	$ 3.0
Purchase price per share | $ / shares	$ 2.35
Conversion of preferred stock to common stock	866,950
Preferred Shares
Subsequent Event [Line Items]
Shares agreed to sell upon agreement	866,950
Preferred stock, par value | $ / shares	$ 0.001
Thomas B. Pickens III | Preferred Shares
Subsequent Event [Line Items]
Shares agreed to sell upon agreement	866,950
Common Stock
Subsequent Event [Line Items]
Shares agreed to sell upon agreement	409,645
Common stock, par value | $ / shares	$ 0.001
Common Stock | Other Investor
Subsequent Event [Line Items]
Shares agreed to sell upon agreement	409,645