Summarized Quarterly Data (Unaudited) - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2018	Mar. 15, 2018	Mar. 05, 2018	Dec. 31, 2017	Nov. 01, 2014
Condensed Financial Statements, Captions [Line Items]
Preferred Stock, Shares Issued		200,000
Number of shares that may be purchased by warrants (shares)	60,000	60,000
Exercise price of right (usd per right)	$ 81.50	$ 81.50		$ 30
2014 MHHA Agreement
Condensed Financial Statements, Captions [Line Items]
Preferred Stock, Shares Issued		200,000
Number of shares that may be purchased by warrants (shares)		60,000
Exercise price of right (usd per right)		$ 81.50
Fair value of common stock not sold					$ 5.5
Fair value of common stock			$ 4.7
Expenses netted against long-term asset			1.4
Guarantee liability			$ 5.5