Stockholders' Equity and Equity Compensation Plans (Tables)

6 Months Ended

Jun. 30, 2017

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 is as follows (shares in thousands):

	Quarter Ended					Six Months Ended
	June 30, 2017					June 30, 2017
	Shares			Weighted- Average Grant Date Fair Value		Shares			Weighted- Average Grant Date Fair Value
Unvested awards, beginning		1,419		$	34.90		1,394		$	31.26
Awards granted		2			40.55		475			39.49
Awards forfeited/cancelled		(11	)		34.63		(20	)		33.44
Awards vested		(19	)		34.65		(458	)		28.61
Unvested awards, ending		1,391		$	34.92		1,391		$	34.92