Stock-Based Compensation - Stock Options (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock Option Activity and Outstanding Options
Options outstanding	798
Granted	18
Forfeited, cancelled or expired	(12)
Exercised	(284)
Options outstanding	520	798
Stock Option Activity and Weighted-Average Exercise Price
Options outstanding, Weighted Average Exercise Price	$ 4.41
Granted, Weighted Average Exercise Price	16.21
Forfeited, canceled or expired, Weighted Average Exercise Price	15.40
Exercises, Weighted Average Exercise Price	3.70
Options outstanding, Weighted Average Exercise Price	$ 5.01	$ 4.41
Options outstanding, Aggregate Intrinsic Value	$ 6,100
Options outstanding, Weighted-Average Remaining Contractual Life	3 years 10 months 24 days
Options exercisable, Number of Options Exercisable	373
Options exercisable, Weighted-Average Exercise Price	$ 3.47
Options exercisable, aggregate intrinsic value	$ 4,900
Options exercisable, Weighted average remaining contractual term	3 years 4 months 24 days
Vested and expected to vest	520
Vested and expected to vest, Weighted Average Exercise Price	$ 5.01
Vested and expected to vest, Aggregate Intrinsic Value	$ 6,100
Vested and expected to vest, remaining contractual term (in years)	3 years 10 months 24 days
Weighted average grant-date fair value of stock options granted	$ 8.94	$ 5.36	$ 4.37
Stock Options [Member]
Stock Option Activity and Weighted-Average Exercise Price
General and administrative	$ 327	$ 592	$ 337
Compensation expense for unvested stock options	$ 400
Weighted average period for unvested stock options	1 year 2 months 12 days