Derivative Financial Instruments - Changes in Outstanding Warrants (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Changes in derivative instrument liability
Balance at the beginning of the period		$ 322		$ 322
Change in fair value of warrants during the quarter	$ 23		$ 1,542	(237)	$ 1,810
Balance at the end of the period	$ 85			$ 85
Derivative instrument liability
Derivative Financial Instruments
Balance of warrants outstanding	210,000			210,000		210,000
Changes in derivative instrument liability
Balance at the beginning of the period		322		$ 322
Change in fair value of warrants during the quarter	$ 23	$ (260)
Balance at the end of the period	$ 85			$ 85