(7) Stock-based Compensation

The Company grants restricted shares of common stock and performance share units to key employees and directors as part of their compensation under the 2009 Long-term Incentive Plan. Future awards of performance share units, restricted stock grants or other equity awards are available under the stockholder approved 2009 Long-term Incentive Plan for 1,983,864 shares of common stock.

During 2015, 2016 and 2017, the Company had $8.1 million, $4.7 million and $5.9 million, respectively, in stock-based compensation expense which is included in general and administrative expenses.   

Restricted Stock

The fair value of restricted stock grants is amortized over the vesting period, generally one to three years, using the straight-line method. Total compensation expense recognized for restricted stock grants was $6.0 million, $3.4 million and $3.9 million for the years ended December 31, 2015, 2016 and 2017, respectively. The fair value of each restricted share on the date of grant is equal to the market price of a share of the Company's stock.

A summary of restricted stock activity for the year ended December 31, 2017 is presented below:

  

Number of
Restricted
Shares

 

  

 

Weighted
Average
Grant Price

 

 

 

 

 

 

 

 

 

Outstanding at January 1, 2017

 

354,986

 

 

 

$15.60

 

Granted

 

500,002

 

 

 

$11.11

 

Vested

 

(185,652

)

 

 

$18.88

 

Forfeitures

 

(49,469

)

 

 

$13.10

 

Outstanding at December 31, 2017

 

619,867

 

 

 

$11.14

 

The per share weighted average fair value of restricted stock grants in 2015, 2016 and 2017 was $26.70, $5.46 and $11.11, respectively. Total unrecognized compensation cost related to unvested restricted stock of $3.8 million as of December 31, 2017 is expected to be recognized over a period of 1.8 years. The fair value of restricted stock which vested in 2015, 2016 and 2017 was $3.7 million, $1.3 million and $1.7 million, respectively.

Performance Share Units

The Company issues PSUs as part of its long-term equity incentive compensation. PSU awards can result in the issuance of common stock to the holder if certain performance criteria is met during a performance period. The performance periods consist of one year, two years and three years, respectively. The performance criteria for the PSUs are based on the Company's annualized total stockholder return ("TSR") for the performance period as compared with the TSR of certain peer companies for the performance period. The costs associated with PSUs are recognized as general and administrative expense over the performance periods of the awards.

The fair value of PSUs was measured at the grant date using the Geometric Brownian Motion Model ("GBM Model") an equation that can create a series of outcomes over time. The GBM model allows the Company to create multiple prospective total return pathways, statistically analyze these simulations, and ultimately make inferences to the most likely path the total return will take. Significant assumptions used in this simulation include the Company's expected volatility and a risk-free interest rate based on U.S. Treasury yield curve rates with maturities consistent with the vesting periods, as well as the volatilities for each of the Company's peers. Assumptions regarding volatility included the historical volatility of each company's stock and the implied volatilities of publicly traded stock options.  

Significant assumptions use to value PSUs in 2015, 2016 and 2017 included:

 

 

For the Years Ended December 31,

 

 

 

2015

 

 

2016

 

 

2017

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Risk free interest rate

 

 

1.1%

 

 

 

0.9%

 

 

 

1.6%

 

Range of implied volatility:

 

 

 

 

 

 

 

 

 

 

 

 

Minimum

 

 

37%

 

 

 

47%

 

 

 

37%

 

Maximum

 

 

65%

 

 

 

92%

 

 

 

134%

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In 2015, the Company granted 94,250 PSUs with a grant date fair value of $0.7 million, or $7.30 per unit.  In 2016, the Company granted 60,015 PSUs with a grant date fair value of $0.4 million, or $7.00 per unit. In 2017, the Company granted 241,814 PSUs with a grant date fair value of $4.4 million, or $18.17 per unit.   The fair value of PSUs is amortized over the vesting period of one to three years, using the straight-line method. Total compensation expense recognized for PSUs was $2.1 million, $1.3 million and $2.0 million for the years ended December 31, 2015, 2016 and 2017, respectively.

A summary of PSU activity for the year ended December 31, 2017 is presented below:

 

 

Number of
PSUs

 

 

 

 

  

Weighted
Average
Grant Price

 

 

 

 

 

 

 

 

 

Outstanding at January 1, 2017

 

134,650

 

 

 

$22.17

 

Granted

 

241,814

 

 

 

$18.17

 

Unearned or forfeited

 

(94,664

)

 

 

$27.01

 

Outstanding at December 31, 2017

 

281,800

 

 

 

$17.12

 

The final number of shares of common stock issued may vary depending upon the performance multiplier, and can result in the issuance of zero to 269,300 shares of common stock based on the achieved performance ranges from zero to two.  As of December 31, 2017, there was $3.0 million of total unrecognized expense related to PSUs, which is being amortized through December 31, 2019.  85,987 PSUs were earned in 2018 and 10,857 were forfeited based on completion of a performance period.

  

 

About Stock Compensation Disclosures

Stock-based compensation disclosures detail the equity awards granted to employees and executives — including stock options, restricted stock units (RSUs), and performance shares — along with the valuation methods and assumptions used to expense them. This section reveals the true cost of talent retention and the alignment between management incentives and shareholder interests.

Key signals: total unrecognized compensation expense and its expected recognition period signal future earnings headwinds from already-granted awards. For stock options, examine Black-Scholes assumptions — expected volatility, risk-free rate, and expected term — as understating any of these reduces reported compensation expense. Compare stock compensation expense as a percentage of revenue against peers to assess dilution cost. Watch vesting schedules for acceleration clauses tied to change-of-control events. Performance-based awards with undemanding targets may indicate weak governance. Add back stock compensation to operating cash flow to calculate a more conservative free cash flow figure.