Stock-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Number of Shares
Beginning stock options outstanding (in shares)	2,149,900	2,056,898	2,071,757
Granted (in shares)	587,862	143,862	233,828
Exercised (in shares)	(13,850)	(3,970)	(143,282)
Forfeited (in shares)	(374,466)	(46,890)	(105,405)
Ending stock options outstanding (in shares)	2,349,446	2,149,900	2,056,898
Weighted Average Exercise Price Per Share
Beginning stock options outstanding (in dollars per share)	$ 9.56	$ 9.86	$ 9.49
Granted (in dollars per share)	4.98	5.82	11.35
Exercised (in dollars per share)	4.86	6.00	6.08
Forfeited (in dollars per share)	9.89	11.72	11.06
Ending stock options outstanding (in dollars per share)	$ 8.39	$ 9.56	$ 9.86
Vested and expected to vest at December 31, 2016
Number of Shares	2,308,956
Weighted Average Exercise Price Per Share (in dollars per share)	$ 8.32
Weighted Average Contractual Life	5 years 2 months 27 days
Aggregate Intrinsic Value	$ 6,970
December 31, 2016
Number of Shares	1,627,204
Weighted Average Exercise Price Per Share (in dollars per share)	$ 9.61
Weighted Average Contractual Life	3 years 8 months 1 day
Aggregate Intrinsic Value	$ 3,897