Stock-Based Compensation

We maintain stock incentive plans for the benefit of certain officers, directors, and employees, including the 2013 Omnibus Incentive Plan (the "2013 Plan"). Compensation expense for stock-based awards is based on the fair values of the awards on the date of grant and is recognized on a straight-line basis over the vesting period of the entire award in the “Labor” line of the Consolidated Statements of Comprehensive Income (Loss). We recognized $0.5 million and $0.6 million of stock-based compensation expense during the three months ended March 31, 2017 and 2016, respectively.

During the three months ended March 31, 2017, the company did not issue any grants of stock-based awards.

Stock Options

Stock options become exercisable in 25% increments on the first four anniversaries of the grant date, and expire on the tenth anniversary of their grant date. Options are granted at an exercise price equal to the market value of the common stock at the market close on the day prior to the grant. Options granted prior to the 2013 Plan will remain outstanding in accordance with their respective terms.

The following table summarizes all stock option activity for the three months ended March 31, 2017:



	Number of Shares		Weighted- Average Grant- Date Fair Value		Weighted Average Remaining Contractual Term(Years)
Balance as of December 31, 2016	3,705,893		$	7.72
Granted	—		—
Exercised	—		—
Forfeited	(21,247	)	6.77
Vested options expired	(688,723	)	11.57
Balance as of March 31, 2017	2,995,923		6.85		5.48

Vested and expected to vest as of March 31, 2017	2,995,923		$	6.85	5.48

Exercisable as of March 31, 2017	2,069,688		$	8.50	3.42

As of March 31, 2017, there was $1.0 million of total unrecognized compensation cost related to unvested stock options. This cost is expected to be recognized over a weighted average period of approximately 2.18 years.

Unvested Shares

Unvested shares vest in three equal increments on the first three anniversaries of their grant date. Unvested shares settle solely in common stock and are treated as equity.

The following table summarizes all unvested share activity for the three months ended March 31, 2017:



	Number of Shares		Weighted- Average Grant- Date Fair Value
Balance as of December 31, 2016	945,252		$	3.76
Granted	—		—
Vested	(62,571	)	5.59
Forfeited	(8,076	)	6.04
Unvested shares outstanding at March 31, 2017	874,605		$	3.61

As of March 31, 2017, there was $2.0 million of total unrecognized compensation cost related to unvested shares. This cost is expected to be recognized over a weighted average period of approximately 1.65 years.

Performance Stock Units

Performance stock units vest in a range between 0% to 100% based upon certain performance criteria in a three-year period. At the end of the performance period, the number of shares paid will be based on our performance versus the target. Performance stock units settle solely in common stock and are treated as equity.

The following table summarizes all performance stock unit activity for the three months ended March 31, 2017:



	Number of Shares		Weighted-Average Grant-Date Fair Value
Balance as of December 31, 2016	844,315		$	2.56
Granted	—		—
Settled	—		—
Forfeited	(43,166	)	6.96
Performance stock units outstanding at March 31, 2017	801,149		$	2.32

As of March 31, 2017, there was $0.9 million of total unrecognized compensation cost related to performance stock units. This cost is expected to be recognized over a weighted average period of approximately 1.91 years.

Phantom Stock Units

Phantom stock units vest in 25% increments on the first four anniversaries of the grant date. Phantom stock units settle solely in cash and are treated as a liability.

The following table summarizes all phantom stock activity for the three months ended March 31, 2017:



	Number of Shares		Weighted- Average Grant- Date Fair Value
Balance as of December 31, 2016	531,820		$	2.69
Granted	—		—
Exercised	—		—
Forfeited	(31,596	)	2.69
Phantom stock units outstanding at March 31, 2017	500,224		$	2.69

As of March 31, 2017, there was $0.5 million of total unrecognized compensation cost related to phantom stock. This cost is expected to be recognized over a weighted average period of approximately 3.04 years. Changes in our stock price will result in adjustments to compensation expense and the corresponding liability over the applicable service period.

Cash Performance Stock Units

Cash performance stock units vest in a range between 0% to 100% based upon certain performance criteria measured over a three-year period. At the end of the performance period, the number of shares settled in cash will be based on our performance versus the target. Cash performance stock units settle solely in cash and are treated as a liability.

The following table summarizes all cash performance stock unit activity for the three months ended March 31, 2017:



	Number of Shares	Weighted- Average Grant- Date Fair Value
Balance as of December 31, 2016	444,005	$	2.69
Granted	—	—
Settled	—	—
Forfeited	—	—
Cash performance stock units outstanding at March 31, 2017	444,005	$	2.69

As of March 31, 2017, we did not expect any of our cash performance stock units to vest due to financial performance. As such, we do not expect to recognize any compensation cost related to cash performance stock units. Changes in our stock price will result in adjustments to compensation expense and the corresponding liability over the applicable service period. Expense is also adjusted up or down based on the current estimate of future performance against the established performance goals.