Equity - Conversions of stock (Details) $ / shares in Units, $ in Millions			12 Months Ended
	Feb. 01, 2019 $ / shares shares	Sep. 20, 2018 shares	Dec. 31, 2019 USD ($) item $ / shares shares	Dec. 31, 2018 $ / shares shares	Jun. 20, 2018 shares	Apr. 03, 2018 $ / shares
Series B convertible preferred stock
Equity
Par value (in dollars per share) | $ / shares			$ 0.01	$ 0.01
Preferred stock outstanding			3	159
Series D convertible preferred stock
Equity
Preferred stock outstanding					5,250
Series C convertible preferred stock
Equity
Par value (in dollars per share) | $ / shares			$ 0.01	$ 0.01
Shares issuable upon conversion of preferred stock			38
Preferred stock outstanding			95,388	95,388
Number of voting rights | item			0
Preferred stock liquidation preference per share | $ / shares			$ 274.88
Preferred stock liquidation preference, value | $			$ 26.2
Common Stock
Equity
Preferred stock liquidation preference per share | $ / shares			$ 692,691.05
Conversion of series D preferred stock into common stock | Series D convertible preferred stock
Equity
Shares converted		1,491		5,500
Common Stock | Series E convertible preferred stock
Equity
Shares issuable upon conversion of preferred stock	1
Common Stock | Series B convertible preferred stock
Equity
Shares issuable upon conversion of preferred stock			1,250
Common Stock | Conversion of common stock into series E preferred stock
Equity
Shares converted	9,993
Common Stock | Conversion of series B preferred stock into common stock
Equity
Shares issued on conversion			1,040	3,970
Common Stock | Conversion of series D preferred stock into common stock
Equity
Shares issued on conversion		237		903
Preferred Stock | Series E convertible preferred stock
Equity
Par value (in dollars per share) | $ / shares	$ 0.01
Preferred Stock | Series B convertible preferred stock
Equity
Preferred stock outstanding			3
Preferred Stock | Series D convertible preferred stock
Equity
Par value (in dollars per share) | $ / shares						$ 0.01
Preferred Stock | Conversion of common stock into series E preferred stock | Series E convertible preferred stock
Equity
Shares issued on conversion	1,192,000
Preferred Stock | Conversion of series B preferred stock into common stock | Series B convertible preferred stock
Equity
Shares converted			156	5,896