Stockholders' Equity and Equity Compensation Plans (Tables)

9 Months Ended

Sep. 30, 2019

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 quarter and nine months ended September 30, 2019 is as follows (shares in thousands):

	Quarter Ended					Nine Months Ended
	September 30, 2019					September 30, 2019
	Shares			Weighted- Average Grant Date Fair Value		Shares			Weighted- Average Grant Date Fair Value
Unvested awards, beginning		1,180		$	42.00		1,145		$	41.64
Awards granted		35			52.40		517			41.62
Awards forfeited/cancelled		(38	)		41.13		(152	)		42.41
Awards vested		(41	)		37.92		(374	)		38.76
Unvested awards, ending		1,136		$	42.48		1,136		$	42.48