Warrants - Warrant Activity (Details)	6 Months Ended
	Jun. 30, 2016 $ / shares shares
Increase (Decrease) in Warrants Outstanding [Roll Forward]
Beginning balance, number of warrants outstanding (shares) | shares	5,666,779
Number of warrants granted during the period (shares) | shares	0
Number of warrants exercised during the period (shares) | shares	0
Number of warrants expired during the period (shares) | shares	(325,902)
Ending balance, number of warrants outstanding (shares) | shares	5,340,877
Beginning balance, weighted-average exercise price (usd per share) | $ / shares	$ 7.14
Weighted-average exercise price, warrants granted during the period (usd per share) | $ / shares	0.00
Weighted-average exercise price, warrants exercised during the period (usd per share) | $ / shares	0.00
Weighted-average exercise price, warrants expired during the period (usd per share) | $ / shares	6.55
Ending balance, weighted-average exercise price (usd per share) | $ / shares	$ 7.18