Stock-based Awards (Details 2) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Stock-based Awards
Stock based compensation expense	$ 9,167	$ 7,396	$ 18,620	$ 11,540
Restricted stock units
Stock-based Awards
Remaining stock based compensation expense for non vested restricted stock units	14,500		$ 14,500
Weighted average period over which remaining stock based compensation expense for unvested awards is expected to be recognized			3 years 6 months 18 days
Stock based compensation expense	$ 1,800	$ 300	$ 4,300	$ 300
Number of Shares
Non-vested at the beginning of period (in shares)			827,997
Granted (in shares)			825,884
Vested (in shares)			(256,025)
Canceled/forfeited (in shares)			(126,552)
Non-vested at the end of the period (in per share)	1,271,304		1,271,304
Weighted-Average Grant Date Fair Value
Non-vested at the beginning of period (in dollars per share)			$ 12.36
Granted (in dollars per share)			15.92
Vested (in dollars per share)			15.17
Canceled/forfeited (in dollars per share)			11.44
Non-vested at the end of the period (in dollars per share)	$ 14.20		$ 14.20