Stock Based Compensation and Other Benefit Plans - Stock Options Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Outstanding at beginning of period (in shares)	3,887,833
Outstanding at beginning of period (in dollars per share)	$ 7.96
Options granted	1,242,856
Weighted-average exercise price of the stock on the date of grant	$ 4.32	$ 9.00	$ 11.20
Exercised (in shares)	(125,017)
Exercised (in dollars per share)	$ 5.80
Expired or cancelled (in shares)	(320,833)
Expired or cancelled (in dollars per share)	$ 8.43
Outstanding at end of period (in shares)	4,684,839	3,887,833
Outstanding at end of period (in dollars per share)	$ 7.02	$ 7.96
Outstanding at end of period	6 years 51 days
Outstanding at end of period	$ 7,130,887
Vested or expected to vest at end of period (in shares)	4,592,882
Vested or expected to vest at end of period (in dollars per share)	$ 7.06
Vested or expected to vest at end of period	6 years 29 days
Vested or expected to vest at end of period	$ 6,878,173
Options exercisable at end of period (in shares)	2,910,115
Options exercisable at end of period (in dollars per share)	$ 7.67
Options exercisable at end of period	4 years 146 days
Options exercisable at end of period	$ 3,235,311