Stockholders' Equity - Warrant Narrative (Details)	9 Months Ended
	Sep. 30, 2019 $ / shares shares
August 2019
Class of Warrant or Right, Title of Security Warrants or Rights Outstanding	Common stock
Warrant Description	The August 2019 Warrants are exercisable for 2,237,500 shares of common stock at an exercise price per share equal to $1.78. The August 2019 Warrants are exercisable beginning six months after the date of issuance and have a term of four years from the date of issuance.
Warrant Outstanding	2,200,000
Exercise Price of Warrant | $ / shares	$ 1.78
Series A
Class of Warrant or Right, Title of Security Warrants or Rights Outstanding	Common stock
Warrant Description	The Series A Warrants were initially exercisable for 1,463,519 shares of common stock at an exercise price per share equal to $4.15, which was adjusted to 2,640,128 shares of the common stock at an exercise price per share equal to $2.3005 on February 27, 2019, which was further adjusted to 3,629,023 shares of common stock at an exercise price per share equal to $1.6736 on March 7, 2019, in each case essentially due to trading at a lower price, pursuant to the terms thereof. Effective August 23, 2019, pursuant to the terms of the Series A Warrants, the exercise price of the Series A Warrants automatically decreased from $1.6736 per share to $0.9267 per share as a result of the announcement of the issuance of the August 2019 Warrants pursuant to the Securities Purchase Agreement. The Series A Warrants were immediately exercisable upon issuance and have a term of five years from the date of issuance. During the three and nine months ended September 30, 2019, 0 and 2.6 million, respectively, Series A Warrants were exercised for approximately $0 and $4.4 million, respectively. As of September 30, 2019, 1.0 million Series A Warrants remain outstanding at an exercise price of $0.9267 per share.
Warrant Outstanding	1,000,000
Exercise Price of Warrant | $ / shares	$ 0.9267
Series B
Class of Warrant or Right, Title of Security Warrants or Rights Outstanding	Common stock
Warrant Description	The Series B Warrants were initially exercisable for no shares of common stock, which was adjusted to 7,951,090 shares of common stock on February 27, 2019 and which was further adjusted to 11,614,483 shares of common stock on March 7, 2019, in each case essentially due to trading at a lower price, pursuant to the terms thereof. The Series B Warrants had an exercise price of $0.001, were immediately exercisable upon issuance and provided for an expiration date of the day following the later to occur of (i) the Reservation Date (as defined therein), and (ii) the date on which the Series B Warrants have been exercised in full (without giving effect to any limitation on exercise contained therein) and no shares remain issuable thereunder. During the nine months ended September 30, 2019, 11.6 million Series B Warrants were exercised for approximately $11,614. As of September 30, 2019, no Series B Warrants remain outstanding and the Series B Warrants are therefore no longer subject to any further changes in warrants or exercise price.
Warrant Outstanding	0