Warrants Outstanding and Exercisable (Details) shares in Thousands	Dec. 31, 2015 $ / shares shares	Dec. 31, 2014 $ / shares	Mar. 31, 2014 $ / shares	Dec. 31, 2013 $ / shares	Dec. 31, 2012 $ / shares
Warrant, exercise price	$ 3.34	$ 3.08	$ 2.47	$ 3.07	$ 7.28
Warrants, Outstanding as of end of period | shares	5,039
Warrants outstanding, weighted average exercise price	3.34
Warrants, Exercisable at end of period | shares	5,039
Warrants exercisable, weighted average exercise price	$ 3.34
$2.01 - $3.08
Warrant exercise, mimimum	2.01
Warrant exercise price, maximum	3.08
Warrants, Outstanding as of end of period | shares	3,761
Warrants outstanding, weighted average remaining contractual life, years	2.39
Warrants outstanding, weighted average exercise price	2.36
Warrants, Exercisable at end of period | shares	3,761
Warrants exercisable, weighted average exercise price	$ 2.36
$6.24 - $10.24
Warrant exercise, mimimum	6.24
Warrant exercise price, maximum	10.24
Warrants, Outstanding as of end of period | shares	1,278
Warrants outstanding, weighted average remaining contractual life, years	0.88
Warrants outstanding, weighted average exercise price	6.24
Warrants, Exercisable at end of period | shares	1,278
Warrants exercisable, weighted average exercise price	$ 6.24