Share-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2019

Share-based Payment Arrangement [Abstract]

Schedule of Share-based Compensation Expense

Total share-based compensation costs that have been included in the Company’s consolidated statements of operations were as follows (in millions):

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Share-Based Compensation Expense Allocation Details:
Cost of services	$	1.5	$	1.5	$	2.8	$	2.8
Selling, general and administrative	3.1		3.5		6.1		6.1
Other	—		0.1		0.1		0.1
Total share-based compensation expense	$	4.6	$	5.1	$	9.0	$	9.0

Summary of Valuation Assumptions

The following table sets forth the significant assumptions used in the Black-Scholes option pricing model and the Monte Carlo simulations and the calculation of share-based compensation expense for the six months ended June 30, 2019 and 2018:

	Six Months Ended June 30,
	2019	2018
Expected dividend yield	—%	—%
Risk-free interest rate	1.9% to 2.5%	2.3% to 2.7%
Expected volatility	40% to 45%	40% to 45%
Expected term (in years)	2.00 to 5.50	2.59 to 6.25

Schedule of Stock Options Activity

A summary of the options activity during the six months ended June 30, 2019 is shown below:

	Shares		Weighted- Average Exercise Price
Outstanding at December 31, 2018	13,884,470		$	5.36
Granted	34,664		9.80
Exercised	(1,474,410	)	5.28
Canceled/forfeited	(94,121	)	2.97
Expired	(3,920	)	12.98
Outstanding at June 30, 2019	12,346,683		$	5.40
Outstanding, vested and exercisable at June 30, 2019	8,940,759		$	6.40
Outstanding, vested and exercisable at December 31, 2018	7,712,264		$	7.37

Schedule of Non-Options Awards Activity

A summary of the RSA, RSU, and PBRSU activity during the six months ended June 30, 2019 is shown below:

										Weighted- Average Grant Date Fair Value
	RSA Shares			RSU Shares			PBRSU Shares			RSA		RSU		PBRSU
Outstanding and unvested at December 31, 2018	1,095,544			1,126,681			4,610,448			$	3.02	$	4.50	$	4.72
Granted	—			704,012			1,034,534			—		10.65		10.28
Vested	(1,094,336		)	(362,101		)	—			3.02		4.16		—
Forfeited	(1,208		)	(72,824		)	(160,681		)	5.38		6.23		6.06
Outstanding and unvested at June 30, 2019	—			1,395,768			5,484,301			$	—	$	7.60	$	5.73
Shares surrendered for taxes for the six months ended June 30, 2019	380,564			106,173			—
Cost of shares surrendered for taxes for the six months ended June 30, 2019 (in millions)	$	3.7		$	1.0		$	—
Shares surrendered for taxes for the six months ended June 30, 2018	404,466			92,834			—
Cost of shares surrendered for taxes for the six months ended June 30, 2018 (in millions)	$	2.2		$	0.7		$	—