Stock-Based Compensation (Stock Options Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Vested and Expected to Vest (in shares)	11,500	31,500	31,500
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding — Beginning of period (in shares)	5,973,049
Granted (in shares)	4,381,500
Exercised (in shares)	(524,504)
Forfeited (in shares)	(810,051)
Expired (in shares)	(346,779)
Outstanding — End of period (in shares)	8,673,215	5,973,049
Vested and Expected to Vest (in shares)	7,906,267
Vested, Number of Stock Options (Shares)	3,788,707
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding — Beginning of period (in USD per share)	$ 10.42
Granted (in USD per share)	7.94
Exercised (in USD per share)	5.96
Forfeited (in USD per share)	11.16
Expired (in USD per share)	13.99
Outstanding — End of period (in USD per share)	9.22	$ 10.42
Vested and Expected to Vest, Weighted Average Exercise Price (USD per share)	9.17
Vested, Weighted Average Exercise Price (USD per share)	$ 8.58
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, Weighted Average Remaining Contractual Life	6 years 8 months 19 days
Vested and Expected to Vest, Weighted Average Remaining Contractual Life	6 years 6 months 11 days
Vested, Weighted Average Remaining Contractual Life	4 years 6 months
Exercised, Aggregate Intrinsic Value	$ 2,656	$ 3,164	$ 2,600	[1]
Outstanding, Aggregate Intrinsic Value	3,247
Vested and Expected to Vest, Aggregate Intrinsic Value	3,247
Vested, Aggregate Intrinsic Value	$ 3,247

[1] Represents the total difference between the Company's stock price at the time of exercise and the stock option exercise price, multiplied by the number of options exercised.