Stock-based Compensation

The Company’s equity incentive program is a long-term retention program that is intended to attract, retain, and provide incentives for talented employees, consultants, officers, and directors and to align stockholder and employee interests. The Company may grant options, stock appreciation rights, restricted stock, restricted stock units (“RSUs”), performance shares, performance units, and other stock-based or cash-based awards to employees, officers, directors, and consultants. Under these programs, stock options may be granted at prices not less than the fair market value on the date of grant for stock options. These options generally vest over 4 years and expire from 5 to 10 years from the date of grant. In addition to time based vesting, market condition based options are subject to a market condition: the closing price of the Company stock must exceed a certain level for a number of trading days within a specified timeframe or the options will be cancelled before their expiration. Restricted stock generally vests over one year. RSUs generally vest over 3 years. Awards granted other than an option or stock appreciation right shall reduce the common stock shares available for grant by 1.75 shares for every share issued.



	December 31,
	2015
Common stock shares available for grant	1,322,579
Standard and market condition based stock options outstanding	3,796,533
Restricted stock awards outstanding	21,356
Restricted stock units outstanding	487,423

Employee Stock Purchase Plan

The Company has an Employee Stock Purchase Plan (“ESPP”). Under the ESPP, eligible employees may purchase common stock through payroll deductions at a purchase price of 85% of the lower of the fair market value of the Company’s stock at the beginning of the offering period or the purchase date. Participants may not purchase more than 2,000 shares in a six-month offering period or purchase stock having a value greater than $25,000 in any calendar year as measured at the beginning of the offering period. A total of 1,000,000 shares of common stock have been reserved for issuance under the ESPP. As of December 31, 2015, 603,558 shares had been purchased since the inception of the ESPP in 1999. Under ASC 718-10, the ESPP is considered a compensatory plan and the Company is required to recognize compensation cost related to the fair value of the award purchased under the ESPP. Shares purchased under the ESPP for the year ended December 31, 2015 are listed below. Shares purchased under the ESPP for the year ended December 31, 2014 are 38,298. The intrinsic value listed below is calculated as the difference between the market value on the date of purchase and the purchase price of the shares.



	Year Ended December 31, 2015
Shares purchased under ESPP	45,820
Average price of shares purchased under ESPP	$	8.00
Intrinsic value of shares purchased under ESPP	$	160,000

Summary of Standard Stock Options

The following table sets forth the summary of standard stock option activity under the Company’s stock option plans for the years ended December 31, 2015, 2014, and 2013:



	Number of Shares		Weighted Average Exercise Price		Weighted Average Fair Value Of Options Granted		Aggregate Intrinsic Value of Options Exercised (In thousands)
Outstanding at January 1, 2013	3,155,631		$	6.65
Granted	1,058,700		10.20		$	5.63
Exercised	(956,633	)	6.68				$	5,774
Forfeited	(10,531	)	8.24
Expired	(20,000	)	9.01
Outstanding at December 31, 2013	3,227,167		7.78
Granted	604,620		10.32		4.93
Exercised	(205,744	)	6.34				1,125
Forfeited	(102,454	)	7.20
Expired	(37,432	)	10.19
Outstanding at December 31, 2014	3,486,157		8.30
Granted	525,840		10.15		4.56
Exercised	(239,071	)	6.82				1,186
Forfeited	(116,425	)	12.38
Expired	(59,968	)	13.75
Outstanding at December 31, 2015	3,596,533		8.45

The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying awards and the quoted price of the Company’s common stock for the options that were in-the-money.

Information regarding standard stock options outstanding at December 31, 2015, 2014, and 2013 is summarized below:



	Number of Shares	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (years)	Aggregate Intrinsic Value (In millions)
December 31, 2013
Options outstanding	3,227,167	$	7.78	5.46	$	9.9
Options vested and expected to vest using estimated forfeiture rates	2,994,044	7.61		5.41	9.6
Options exercisable	1,774,546	6.67		4.95	7.5
December 31, 2014
Options outstanding	3,486,157	$	8.30	4.85	$	6.6
Options vested and expected to vest using estimated forfeiture rates	3,319,308	8.21		4.80	6.6
Options exercisable	2,023,024	7.18		4.26	6.0
December 31, 2015
Options outstanding	3,596,533	$	8.45	4.23	$	12.5
Options vested and expected to vest using estimated forfeiture rates	3,452,487	8.36		4.16	12.3
Options exercisable	2,252,744	7.59		3.56	9.9

Additional information regarding standard options outstanding as of December 31, 2015 is as follows:



	Options Outstanding				Options Exercisable
Range of Exercise Prices	Number Outstanding	Weighted Average Remaining Contractual Life (Years)	Weighted Average Exercise Price		Number Exercisable	Weighted Average Exercise Price
$2.70 - $3.72	17,938	3.19	$	2.75	17,938	$	2.75
3.85 - 3.85	600,000	3.87	3.85		600,000	3.85
4.24 - 6.12	493,241	2.92	5.94		464,786	5.93
6.23 - 8.09	410,349	5.35	7.52		167,009	6.85
8.18 - 9.19	440,433	4.35	8.90		236,822	8.85
9.20 - 9.20	44,300	2.54	9.20		44,300	9.20
9.53 - 9.53	810,000	4.18	9.53		384,374	9.53
9.65 - 12.20	392,427	5.48	11.50		138,690	11.49
12.22 - 15.12	287,845	5.08	13.16		98,825	14.32
16.57 - 16.57	100,000	1.74	16.57		100,000	16.57
$2.70 - $16.57	3,596,533	4.23	$	8.45	2,252,744	$	7.59

Summary of Market Condition Based Stock Options

In 2014, the Company began granting options that are subject to both time-based vesting and a market condition. For these options, the closing price of the Company stock must exceed a certain level for a number of trading days within a specified timeframe or the options will be cancelled before the seven year life of the options. The following table sets forth the summary of the market condition based option activity under the Company’s stock option plans for the years ended December 31, 2015 and 2014:



	Number of Shares	Weighted Average Exercise Price		Weighted Average Fair Value Of Options Granted	Aggregate Intrinsic Value of Options Exercised(In thousands)
Outstanding at January 1, 2014	—	$	—
Granted	50,000	11.94		5.71
Exercised	—	—			$	—
Forfeited	—	—
Expired	—	—
Outstanding at December 31, 2014	50,000	11.94
Granted	150,000	8.09		3.64
Exercised	—	—			—
Forfeited	—	—
Expired	—	—
Outstanding at December 31, 2015	200,000	9.05

Information regarding these market condition based stock options outstanding at December 31, 2015 and 2014 is summarized below:



	Number of Shares	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (years)	Aggregate Intrinsic Value(In millions)
December 31, 2014
Options outstanding	50,000	$	11.94	6.15	$	—
Options vested and expected to vest using estimated forfeiture rates	45,430	11.94		6.15	—
Options exercisable	—	—		—	—
December 31, 2015
Options outstanding	200,000	$	9.05	5.92	$	0.5
Options vested and expected to vest using estimated forfeiture rates	184,125	9.12		5.90	0.5
Options exercisable	—	—		—	—

Additional information regarding market condition based stock options outstanding as of December 31, 2015 is as follows:



	Options Outstanding				Options Exercisable
Range of Exercise Prices	Number Outstanding	Weighted Average Remaining Contractual Life (Years)	Weighted Average Exercise Price		Number Exercisable	Weighted Average Exercise Price
$8.09 - $11.94	200,000	5.92	$	9.05	—	$	—

Summary of Restricted Stock Units

RSU activity for the years ended December 31, 2015, 2014, and 2013 was as follows:



	Number of Shares		Weighted Average Grant Date Fair Value		Fair Value of Released RSU’s (In thousands)
Outstanding at January 1, 2013	708,651
Awarded	294,150		$	7.12
Released	(303,882	)			$	2,806
Forfeited	(30,863	)
Outstanding at December 31, 2013	668,056
Awarded	265,630		11.35
Released	(317,970	)			3,491
Forfeited	(50,825	)
Outstanding at December 31, 2014	564,891
Awarded	281,290		8.16
Released	(299,277	)			2,626
Forfeited	(59,481	)
Outstanding at December 31, 2015	487,423

Information regarding RSU’s at December 31, 2015, 2014, and 2013 is summarized below:



	Number of Shares	Weighted Average Remaining Contractual Life (years)	Aggregate Intrinsic Value(In millions)		Fair Value(In millions)
December 31, 2013
RSUs outstanding	668,056	0.91	$	6.9	$	6.9
RSUs vested and expected to vest using estimated forfeiture rates	583,711	0.89	6.1
December 31, 2014
RSUs outstanding	564,891	0.84	$	5.3	$	5.3
RSUs vested and expected to vest using estimated forfeiture rates	502,411	0.80	4.8
December 31, 2015
RSUs outstanding	487,423	0.90	$	5.7	$	5.7
RSUs vested and expected to vest using estimated forfeiture rates	414,934	0.87	4.8

The aggregate intrinsic value is calculated as the market value as of the end of the reporting period.

Summary of Restricted Stock Awards

Restricted stock award activity for the years ended December 31, 2015, 2014, and 2013 was as follows:



	Number of Shares		Weighted Average Grant Date Fair Value		Total Fair Value of Awards Released (In thousands)
Outstanding at January 1, 2013	44,000		$	5.34
Awarded	44,000		14.09
Released	(44,000	)	5.34		$	676
Forfeited	—
Outstanding at December 31, 2013	44,000		14.09
Awarded	35,364		10.97
Released	(44,000	)	14.09		483
Forfeited	—
Outstanding at December 31, 2014	35,364		10.97
Awarded	21,356		12.26
Released	(35,364	)	10.97		434
Forfeited	—
Outstanding at December 31, 2015	21,356		12.26

Stock-based Compensation

Valuation and amortization methods — The Company uses the Black-Scholes-Merton option pricing model (“Black-Scholes model”), single-option approach to determine the fair value of standard stock options and ESPP shares. All share-based payment awards are amortized on a straight-line basis over the requisite service periods of the awards, which are generally the vesting periods. Stock-based compensation expense recognized at fair value includes the impact of estimated forfeitures. The Company estimates future forfeitures at the date of grant and revises the estimates if necessary, in subsequent periods if actual forfeitures differ from these estimates. The determination of the fair value of share-based payment awards on the date of grant using an option pricing model is affected by the Company’s stock price as well as assumptions regarding a number of complex and subjective variables. These variables include actual and projected employee stock option exercise behaviors that impact the expected term, the Company’s expected stock price volatility over the term of the awards, risk-free interest rate, and expected dividends.

Expected term — The Company estimates the expected term of options granted by calculating the average term from the Company’s historical stock option exercise experience. The expected term of ESPP shares is the length of the offering period. The Company used the simplified method approved by the SEC to determine the expected term for options granted prior to December 31, 2007.

Expected volatility — The Company estimates the volatility of its common stock taking into consideration its historical stock price movement and its expected future stock price trends based on known or anticipated events.

Risk-free interest rate — The Company bases the risk-free interest rate that it uses in the option pricing model on U.S. Treasury zero-coupon issues with remaining terms similar to the expected term on the options.

Expected dividend — The Company does not anticipate paying any cash dividends in the foreseeable future and therefore uses an expected dividend yield of zero in the option-pricing model.

Forfeitures — The Company is required to estimate future forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. The Company uses historical data to estimate pre-vesting option forfeitures and records stock-based compensation expense only for those awards that are expected to vest.

The Company uses the Monte-Carlo Simulation model to value the stock options with a market condition. Valuation techniques such as a Monte-Carlo Simulation model have been developed to value path-dependent awards. The Monte-Carlo Simulation model is a generally accepted statistical technique used, in this instance, to simulate a range of future stock prices for the Company.

The assumptions used to value option grants under the Company’s stock plans are as follows:



	Standard Stock Options
	2015		2014		2013
Expected life (in years)	4.7		4.7		4.9
Interest rate	1.4	%	1.4	%	0.8	%
Volatility	56	%	57	%	70	%
Dividend yield	—	%	—	%	—	%



	Market Condition Based Stock Options
	2015		2014
Expected life (in years)	7.0		7.0
Interest rate	1.9	%	2.2	%
Volatility	65	%	66	%
Dividend yield	—	%	—	%



	Employee Stock Purchase Plan
	2015		2014		2013
Expected life (in years)	0.5		0.5		0.5
Interest rate	0.1	%	0.1	%	0.1	%
Volatility	48	%	43	%	67	%
Dividend yield	—	%	—	%	—	%

Total stock-based compensation recognized in the consolidated statements of income is as follows:



	Year Ended December 31,
	2015		2014		2013
Income Statement Classifications	(In thousands)
Sales and marketing	$	1,116	$	1,117	$	747
Research and development	1,303		1,267		1,040
General and administrative	3,051		2,911		2,857
Total	$	5,470	$	5,295	$	4,644

As of December 31, 2015, there was $6.7 million of unrecognized compensation cost, adjusted for estimated forfeitures, related to non-vested stock options, restricted stock awards and RSU’s granted to the Company’s employees and directors. This cost will be recognized over an estimated weighted-average period of approximately 2.45 years for standard options, 2.92 years for market condition based options, 0.43 years for restricted stock awards and 1.59 years for RSU’s. Total unrecognized compensation cost will be adjusted for future changes in estimated forfeitures.