(

)

Stock Based Compensation

The Company recognizes compensation costs for stock option

s awarded to employees based on their grant-date fair value. The value of each stock option is estimated on the date of grant using the Black-Scholes option-pricing model. The weighted-average fair value per share for the stock options granted to employees during the

nine

months ended

September 30, 2017

was

$20.14.

The weighted-average fair value per share for the stock options granted to employees during the

nine

months ended

September 30, 2016

was

$13.82.

For the

three

months ended

September 30, 2017

and

2016,

the Company recorded

$1,187

and

$1,012,

respectively, in “Selling, general and administrative expenses” for stock options. For the

nine

months ended

September 30, 2017

and

2016,

the Company recorded

$3,313

and

$2,836,

respectively, in “Selling, general and administrative expenses” for stock options. As of

September 30, 2017,

the total compensation cost related to unvested stock options

not

yet recognized was

$7,224.

The cost will be amortized on a straight-line basis over the remaining weighted-average vesting period of

1.9

years.

The following table is a summary of the Company

’s stock options:

Options	Number of Shares			Weighted Average Exercise Price

Outstanding at December 31, 2016		1,519,338		$	25.22
Granted		39,037			54.15
Exercised		(61,249	)		11.83
Outstanding at March 31, 2017		1,497,126			26.52
Granted		19,598			58.98
Exercised		(162,431	)		13.84
Outstanding at June 30, 2017		1,354,293			28.51
Exercised		(55,950	)		8.48
Outstanding at September 30, 2017		1,298,343			29.37
Exercisable at September 30, 2017		449,959		$	21.09

The aggregate intrinsic values for all stock options exercised for the

three

and

nine

months ended

September 30, 2017

were

$2,669

and

$12,011,

respectively. The aggregate intrinsic values for all stock options exercised for the

three

and

nine

months ended

September 30, 2016

were

$173

and

$8,195,

respectively. The aggregate intrinsic values for all stock options outstanding and exercisable as of

September 30, 2017

were

$33,350

and

$15,256,

respectively.

The following table is a summary of the Company’s unvested stock options, restricted stock and performance shares for which the requisite service period has

not

been rendered but that are expected to vest on the achievement of a performance condition:

	Unvested Stock Options					Unvested Restricted Stock					Unvested Performance Shares
	Number of Shares			Weighted- Average Grant-Date Fair Value		Number of Shares			Weighted- Average Grant-Date Fair Value		Number of Shares			Weighted- Average Grant-Date Fair Value

Unvested at December 31, 2016		817,540		$	12.50		260		$	41.05		316,750		$	30.08
Granted		39,037			21.02		-			-		-			-
Vested during period		(14,975	)		8.16		-			-		-			-
Unvested at March 31, 2017		841,602			12.97		260			41.05		316,750			30.08
Granted		19,598			18.37		9,496			58.98		5,750			41.36
Vested during period		(12,816	)		8.50		(260	)		41.05		-			-
Unvested at June 30, 2017		848,384			13.17		9,496			58.98		322,500			30.28
Vested during period		-			-		-			-		(150,000	)		17.81
Unvested at September 30, 2017		848,384		$	13.17		9,496		$	58.98		172,500		$	41.12

For the

three

months ended

September 30, 2017

and

2016,

the Company recorded

$280

and

$240,

respectively, in “Selling, general and administrative expenses” for restricted stock awards. For the

nine

months ended

September 30, 2017

and

2016,

the Company recorded

$474

and

$406,

respectively, in “Selling, general and administrative expenses” for restricted stock awards. As of

September 30, 2017,

total compensation cost related to unvested restricted stock

not

yet recognized was

$93.

The cost will be amortized on a straight-line basis over the remaining weighted-average vesting period of

0.1

years.

The Company granted equity-settled performance shares (“PS”) to certain executives. PS awards provide the recipient the right to receive a certain number of shares of the Company’s common stock in the future, which depends on the Company’s level of achievement of net revenue and EBITDA growth as compared to the net revenue and EBITDA growth of the members of a specified peer group of companies over a

three

year period. For the

three

months ended

September 30, 2017

and

2016,

the Company recorded

$821

and

$637,

respectively, in “Selling, general and administrative expenses” related to these PS awards. For the

nine

months ended

September 30, 2017

and

2016,

the Company recorded

$2,534

and

$1,947,

respectively, in “Selling, general and administrative expenses” related to these PS awards. As of

September 30, 2017,

total compensation cost related to unvested performance shares

not

yet recognized was

$3,143.

The cost will be amortized on a straight-line basis over the remaining weighted-average vesting period of

1.3

years.