Stock-Based Compensation - Stock Options (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Option Activity and Outstanding Options
Options outstanding	993
Granted	154
Forfeited, cancelled or expired	(252)
Exercised	(97)
Options outstanding	798	993
Stock Option Activity and Weighted-Average Exercise Price
Options outstanding, Weighted Average Exercise Price	$ 6.73
Granted, Weighted Average Exercise Price	$ 8.52
Forfeited, canceled or expired, Weighted Average Exercise Price	$ 16.46
Exercises, Weighted Average Exercise Price	$ 3.90
Options outstanding, Weighted Average Exercise Price	$ 4.41	$ 6.73
Options outstanding, Aggregate Intrinsic Value	$ 8,600,000
Options outstanding, Weighted-Average Remaining Contractual Life	4 years 3 months 18 days
Options exercisable, Number of Options Exercisable	500
Options exercisable, Weighted-Average Exercise Price	$ 3.25
Options exercisable, aggregate intrinsic value	6,000,000
Options exercisable, Weighted average remaining contractual term	3 years 4 months 24 days
Vested and expected to vest	797
Vested and expected to vest, Weighted Average Exercise Price	$ 4.41
Vested and expected to vest, Aggregate Intrinsic Value	8,600,000
Vested and expected to vest, remaining contractual term (in years)	4 years 3 months 18 days
Weighted average grant-date fair value of stock options granted	$ 5.36	$ 4.37	$ 1.89
Stock Options [Member]
Stock Option Activity and Weighted-Average Exercise Price
General and administrative	592,000	337,000	355,000
Compensation expense for unvested stock options	$ 700,000
Weighted average period for unvested stock options	1 year 6 months