Stockholders' Equity and Equity Compensation Plans (Tables)

6 Months Ended

Jun. 30, 2015

Stockholders Equity Note [Abstract]

Summary of Unvested Restricted Common Stock Activity

Stock-Based Awards. A summary of our unvested restricted common stock activity during the second quarter and six months ended June 30, 2015 is as follows (shares in thousands):

	Quarter Ended June 30, 2015					Six Months Ended June 30, 2015
	Shares			Weighted- Average  Grant Date Fair Value		Shares			Weighted- Average  Grant Date Fair Value
Unvested awards, beginning		2,310		$	25.30		2,311			$	22.81
Awards granted		7			31.57		595				29.67
Awards forfeited/cancelled		(23	)		24.84		(41	)			24.01
Awards vested		(11	)		21.60		(582	)			19.85
Unvested awards, ending		2,283		$	25.34		2,283			$	25.34