Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Assumptions Used to Determine Fair Value of Stock Options Granted

The assumptions used to determine the fair value of the stock options granted during the nine months ended September 30, 2016 and 2015 were as follows:

	Nine Months Ended September 30,
	2016			2015
Weighted-average fair value options granted	$	10.74		$	16.48
Average risk-free interest rate		1.41	%		1.46	%
Expected stock price volatilities		50.3	%		47.0	%
Dividend yield	None			None
Expected stock option life (years)		5.78			6.06

Summary of Stock Option Activity

Stock option awards as of December 31, 2015 and September 30, 2016, and changes during the nine months ended September 30, 2016, were as follows:

	Options			Weighted-Average Exercise Price		Aggregate Intrinsic Value (thousands)		Weighted-Average Exercise Term (years)
Outstanding at December 31, 2015		5,078,297		$	19.66	$	41,107		8.21
Granted		131,816			22.54
Forfeited		(795,391	)		26.39
Exercised		(1,227,543	)		9.63
Outstanding at September 30, 2016		3,187,179			21.96		67,059		7.85
Vested and expected to vest at September 30, 2016		2,675,453			21.11		58,572		7.85
Exercisable at September 30, 2016		1,069,786		$	16.61	$	28,246		6.79

Non-vested Restricted Stock Units and Restricted Stock Awards

Non-vested restricted stock units and restricted stock awards as of December 31, 2015 and September 30, 2016, and changes during the nine months ended September 30, 2016 were as follows:

	Restricted Stock Units					Restricted Stock Awards
	Shares			Weighted-Average Grant Date Fair Value		Shares			Weighted-Average Grant Date Fair Value
Outstanding at December 31, 2015		888,483		$	27.85		67,744		$	42.01
Granted		952,239			28.35		—			—
Forfeited		(178,305	)		27.19		—			—
Vested		(52,810	)		37.32		(67,744	)		42.01
Outstanding at September 30, 2016		1,609,607		$	27.91		—		$	—