Warrants, Restricted Stock, Restricted Stock Units, Options and Option Matching Rights Warrants, Restricted Stock, Restricted Stock Units, Options and Option Matching Rights - Option Matching Rights (Details) - $ / shares	Aug. 19, 2009	Dec. 31, 2018	Mar. 15, 2018	Jan. 24, 2018	Dec. 31, 2017	Dec. 31, 2016	Feb. 17, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of securities declined to exercise (in shares)						204,706
Class of warrant or right, outstanding (in shares)					133,000
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
Option Matching Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Class of Warrant or Right, Number of Securities Exercised to Trigger Option Matching Rights	200,000
Class of Warrant or Right, Option Exercise Notice	5 days
Class of Warrant or Right, Option Exercise, Second Notice	10 days
Number of securities declined to exercise (in shares)							204,706
Class of Warrant or Right, Option Cancellation Notice	10 days
Class of warrant or right, outstanding (in shares)					3,000
Number of shares that may be purchased by warrants (shares)				1,666
Exercise price of right (usd per right)				$ 14.95