Warrants Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Feb. 24, 2020	Mar. 31, 2020	Mar. 31, 2019	Mar. 10, 2020	Dec. 11, 2019	Apr. 28, 2017
Class of Warrant or Right [Line Items]
Warrants, exercise price (in dollars per share)				$ 0.68
Beneficial conversion charge		$ 412	$ 0
Series B Warrant
Class of Warrant or Right [Line Items]
Number of warrants held (in shares)	3,638,780
Warrants, exercise price (in dollars per share)						$ 13.00
Series C Warrants
Class of Warrant or Right [Line Items]
Number of common stock or warrants in each unit (in shares)				1
Number of warrants held (in shares)				25,367,646
Series D Warrants
Class of Warrant or Right [Line Items]
Number of common stock or warrants in each unit (in shares)				1
Number of warrants held (in shares)				25,367,646
Exchange Agreement
Class of Warrant or Right [Line Items]
Common stock warrants issued (in shares)	2,040,757
Exchange Agreement | Series B Warrant
Class of Warrant or Right [Line Items]
Number of common stock or warrants in each unit (in shares)	0.61
Number of warrants held (in shares)	3,373,900	530,381
Warrants, exercise price (in dollars per share)					$ 0.37
Common Stock Warrants
Class of Warrant or Right [Line Items]
Exchange of warrants		$ 2,470