Stock-based Awards (Details 2) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Stock-based Awards
Stock based compensation expense	$ 7,531	$ 9,440	$ 26,151	$ 20,978
Restricted stock units
Stock-based Awards
Remaining stock based compensation expense for non vested restricted stock units	16,600		$ 16,600
Weighted average period over which remaining stock based compensation expense for unvested awards is expected to be recognized			3 years 4 months 16 days
Stock based compensation expense	$ 1,400	$ 800	$ 5,700	$ 1,200
Number of Shares
Non-vested at the beginning of period (in shares)			827,997
Granted (in shares)			1,333,168
Vested (in shares)			(364,801)
Canceled/forfeited (in shares)			(184,372)
Non-vested at the end of the period (in per share)	1,611,992		1,611,992
Weighted-Average Grant Date Fair Value
Non-vested at the beginning of period (in dollars per share)			$ 12.36
Granted (in dollars per share)			12.06
Vested (in dollars per share)			14.58
Canceled/forfeited (in dollars per share)			11.38
Non-vested at the end of the period (in dollars per share)	$ 11.72		$ 11.72