Stock-Based Compensation (Tables)

As of June 30, 2018, the unrecognized compensation cost and remaining weighted-average amortization related to stock-based awards were as follows:

			Performance-
		Time-based	based
		Restricted	Restricted
	Stock	Stock	Stock
(in thousands, except remaining period data)	Options	Units	Units⁽¹⁾
Unrecognized compensation cost	$ 185	$ 17,183	$ 4,732
Remaining weighted-average
amortization period	0.7 years	2.6 years	1.6 years

⁽¹⁾ Based on the probable achievement of the performance goals identified in each award.

The following table summarizes activities relating to the Company’s stock options:

The following table summarizes the activities related to the Company’s time-based restricted stock units:

		Weighted-
	Number of	Average
	Units	Grant Date
	(in thousands)	Fair Value
Non-vested units outstanding as of December 31, 2017	593	$27.47
Granted	385	29.67
Vested	(209)	26.51
Forfeited	(70)	27.02
Non-vested units outstanding as of June 30, 2018	699	$29.01

The following table summarizes the activities related to the Company’s performance-based restricted stock units:

		Weighted-
	Number of	Average
	Units	Grant Date
	(in thousands)	Fair Value
Non-vested units outstanding as of December 31, 2017	346	$26.88
Granted ⁽¹⁾	109	29.92
Forfeited	(145)	23.97
Non-vested units outstanding as of June 30, 2018	310	$29.31

⁽¹⁾Represents target number of units that can vest based on the achievement of the performance goals.