The Company included stock-based compensation expense related to all of the Company’s stock-based payments awards in various operating expense categories for the years ended December 31, 2019, 2018 and 2017 as follows:


	Years Ended December 31,
	2019		2018		2017
Stock-based compensation expense:
Technology and development	$	818	$	492	$	615
Sales and marketing	2,196		1,470		2,062
General and administrative	2,745		1,858		2,044
Total in continuing operations	$	5,759	$	3,820	$	4,721
Discontinued operations	—		—		673
Total stock-based compensation expense	$	5,759	$	3,820	$	5,394

The Company recognizes compensation expenses for the value of its stock-based payment awards, using the straight-line method, over the requisite service period of each of the awards, net of actual forfeitures. In the event of modification of the conditions on which stock-based payment awards were granted, an additional expense is recognized for any modification that increases the total fair value of the stock-based payment arrangement or is otherwise beneficial to the employee, other service provider or non-employee at the modification date. During 2019 the Company modified certain stock awards, resulting in the recognition of stock-based compensation of $383 during the period.

In August 2017, in connection with the consummation of the sale of the Company’s buyer platform, the Company modified certain restricted stock unit awards held by employees of the buyer platform to provide for pro-rated vesting of such awards for the current year vesting cycle, based on the number of days elapsed from the last vesting date through the date of the transaction. The incremental expense arising from this modification was $45. Additionally, as a result of the sale of the buyer platform, the Company reclassified stock-based compensation expense relating to the employees of the buyer platform of $673 for the year-ended December 31, 2017, which was recorded in Net Income from discontinued operations in the consolidated statement of operations.

On September 20, 2017, the Company entered into an agreement with the Company’s President of Publisher Platforms that resulted in a separation date of October 6, 2017. The agreement provided acceleration of 100% of the unvested shares subject to any stock option or restricted stock unit award issued to him by the Company. The expense arising from this modification was $729.

On June 26, 2013, the Company adopted the 2013 Equity Incentive Plan (the “2013 Plan”). The Company has stock option awards outstanding under five stock-based incentive plans as of December 31, 2019, including two plans that were assumed as part of the acquisition of ScanScout. The Company has restricted stock unit awards outstanding, under its 2013 Plan, as of December 31, 2019.

The Company’s initial share reserve under the 2013 Plan upon adoption was 1,333,333 shares of common stock. The number of shares reserved for issuance under the 2013 Plan increases automatically on the first day of January of each year, for a period of ten years, continuing through and including January 1, 2023, by the lesser of 4% of the total number of shares of common stock on the immediately preceding December 31^st, or a lesser number of shares determined by the Company’s board of directors. The maximum term for stock option awards granted under the 2013 Plan may not exceed ten years from the date of grant. The 2013 Plan will terminate ten years from the date of approval unless it is terminated earlier by the compensation committee of the board of directors.


	Options Outstanding						Options Exercisable
	Options	Weighted Average Remaining Contractual Life	Weighted Average Exercise Price		Options	Weighted Average Remaining Contractual Life	Weighted Average Exercise Price
Range of Exercise Prices	Outstanding	(Years)	Per Share		Exercisable	(Years)	Per Share
$1.11 - $1.94	658,915	2.25	$	1.86	635,477	2.55	$	1.85
$2.00 – $2.88	1,305,000	5.92	2.40		894,269	4.79	2.45
$3.60 – $4.83	1,921,869	4.03	4.22		1,463,677	2.61	4.18
$5.01 – $5.90	1,019,324	2.75	5.56		437,037	0.71	5.57
$6.75 – $8.37	422,648	4.83	8.17		163,164	3.03	7.59
	5,327,756	3.96	$	3.70	3,593,624	2.74	$	4.00


	Number of Stock Option Awards Outstanding	Weighted Average Exercise Price Per Share
December 31, 2018⁽¹⁾	6,348,251	$	3.73
Stock option awards granted	884,479	6.06
Stock option awards forfeited	(215,813)	4.33
Stock option awards exercised	(1,689,161)	4.05
Stock option awards outstanding as of December 31, 2019	5,327,756	$	4.00

Stock option awards vested and exercisable as of December 31, 2019	3,593,624	$	4.00

(1) Includes certain employment inducement stock option awards granted outside of the Company’s stockholder approved equity compensation plans. These grants are generally subject to the same terms and conditions as applied to awards granted under the Company’s 2013 Plan. Stock option awards are generally granted at the fair market value of the Company’s common stock on the date of grant, generally vest over periods up to four years, have a one year cliff with monthly vesting thereafter, and have terms not to exceed 10 years.


	Years Ended December 31,
	2019		2018		2017
Aggregate fair value of stock option awards vested	$	1,183	$	374	$	644
Aggregate intrinsic value of outstanding stock option awards	954		1,270		5,503
Aggregate intrinsic value of stock option awards exercised	5,533		1,713		748
Weighted-average grant-date fair value per share of stock option awards granted	3.21		1.91		1.13
Cash proceeds received from stock option awards exercised	$	6,749	$	1,845	$	699

The fair value for stock option awards was estimated at the date of grant using a Black-Scholes option pricing model (other than with respect to the Performance Option (as defined below)). Calculating the fair value of the stock option awards requires

subjective assumptions, including, but not limited to, the expected term of the stock option awards and stock price volatility. The Company estimates the expected life of stock option awards granted based on the simplified method, which the Company believes, is representative of the actual characteristics of the awards. The Company estimates the volatility of its common stock on the date of grant based on the historic volatility of the Company. Risk-free interest rates are based on yields from United States Treasury zero-coupon issues with a term consistent with the expected term of the awards in effect at the time of grant. Forfeitures are based on actual forfeitures in the given period. The Company has never declared or paid any cash dividends and has no current plan to do so. Consequently, it used an expected dividend yield of zero.


	2019		2018		2017
Volatility	57% - 57%		49% - 55%		49% - 50%
Risk-free interest rate	1.68% - 2.55%		2.37% - 3.01%		1.85% to 2.02%
Expected life (in years)	5.45 - 5.54		5.32 - 5.58		5.65 - 5.67
Dividend yield	0.00	%	0.00	%	0.00	%

There was $3,390 of total unrecognized compensation cost related to non-vested stock option awards granted under the Company’s equity incentive plans as of December 31, 2019. This cost is expected to be recognized over a weighted-average period of 2.63 years.


	Number of Restricted Stock Awards Outstanding	Weighted Average Grant Date Fair Value Per Share
Non-vested restricted stock unit awards outstanding as of December 31, 2018	2,350,054	$	3.00
Restricted stock unit awards granted	1,364,236	6.10
Restricted stock unit awards forfeited	(265,681)	4.32
Restricted stock unit awards vested	(973,568)	2.91
Non-vested restricted stock unit awards outstanding as of December 31, 2019	2,475,041	4.61

Restricted stock unit awards are generally granted at the fair market value of the Company’s common stock on the date of grant and vest on an annual basis over periods up to four years. Forfeitures are based on actual forfeitures in the given period.

As restricted stock unit awards vest, they are settled on a net-share basis. Upon settlement, certain shares underlying each restricted stock unit award are withheld to satisfy income tax withholding obligations, which is based on the value of the restricted stock unit award on the settlement date as determined by the closing fair market value of the Company’s common stock, relating to the employees’ minimum statutory obligation.

There were $5,891 of total unrecognized compensation cost related to non-vested restricted stock unit awards granted under the Company’s equity incentive plans as of December 31, 2019. This cost is expected to be recognized over a weighted-average period of 2.49 years.

On April 22, 2014, the Company’s board of directors adopted the 2014 Employee Stock Purchase Plan (“2014 ESPP”), which was approved by the Company’s stockholders at the 2014 annual meeting of stockholders on June 16, 2014. The 2014 ESPP allows eligible participants to purchase shares of the Company’s common stock generally at six-month intervals, or offering periods, at a price equal to 85% of the lower of (i) the fair market value at the beginning of the offering period or (ii) the fair market value at the end of the offering period, or the purchase date.

Employees purchase shares of common stock through payroll deductions, which may not exceed 15% of their total base salary. The 2014 ESPP imposes certain limitations upon an employee’s right to purchase shares, including the following: (1) no employee may purchase more than 5,000 shares on any one purchase date and (2) no employee may purchase shares with a fair market value in excess of $25 in any calendar year.

No more than 2,000,000 shares of common stock are reserved for future issuance under the 2014 ESPP. As of December 31, 2019, the Company had 685,720 shares of common stock reserved for future issuance under the 2014 ESPP.

The fair value for each award under the 2014 ESPP was estimated at the date of grant, at the beginning of the offering period, using a Black-Scholes option pricing model. Calculating the fair value of the ESPP awards requires subjective assumptions, including, but not limited to, the expected term of the ESPP award and stock price volatility. The Company estimates the expected life of the awards granted under the 2014 ESPP based on the duration of the offering periods, which is six months. The Company estimates the volatility of its common stock on the date of grant based on the Company's historic volatility. Risk-free interest rates are based on yields from United States Treasury zero-coupon issues with a term consistent with the expected term of the awards in effect at the time of grant. Forfeitures are recognized as they occur. The Company has never declared or paid any cash dividends and has no current plan to do so. Consequently, it used an expected dividend yield of zero.

On July 10, 2017, the Company granted certain employment inducement awards to its newly appointed CEO. This grant included a performance option award for 450,000 shares of the Company’s common stock, which provides that 50% of the shares subject to the option will vest as of the date on which the 30-day moving average of the Company’s common stock exceeds $4.00 per share (as adjusted to account for any stock splits or other adjustments), and 50% of the shares subject to the option will vest as of the date on which the 30-day moving average of the Company’s common stock exceeds $5.00 per share (as adjusted to account for any stock splits or other adjustments), provided, in each case that he continues to provide services to the Company on each such vesting date.

With respect to this performance option award, stock-option expense will be recorded over the vesting period for each tranche’s vesting period based on the expected achievement of the vesting condition. For these purposes, the vesting period for the $4.00 stock-option market condition is 1.27 years and the vesting period for the $5.00 market condition is 1.75 years.