Stock-based Compensation

2017 Employee Stock Purchase Plan—The Company’s 2017 Employee Stock Purchase Plan (“2017 ESPP”) became effective on July 27, 2017 and enables eligible employees to purchase shares of the Company’s common stock at a discount. Purchases will be accomplished through participation in discrete offering periods. The Company initially reserved 1,600,000 shares of common stock for issuance under the 2017 ESPP. The number of shares reserved for issuance under the 2017 ESPP will increase automatically on January 1 of each calendar year beginning after the first offering date and continuing through January 1, 2028 by the number of shares equal to the lesser of 1% of the total outstanding shares of the Company’s common stock as of the immediately preceding December 31 or an amount determined by the board of directors. On February 22, 2018, the board of directors determined to increase to the number of shares reserved for issuance under the 2017 ESPP by 814,688 shares. On each purchase date, participating employees purchase the Company’s common stock at a price per share equal to 85% of the lesser of (1) the fair market value of the Company’s common stock on the first trading day of the offering period, and (2) the fair market value of the Company’s common stock on the purchase date. The initial offering period began on January 1, 2018. The Company has recognized compensation cost and employee deductions have commenced. Offering periods last 6 months each, and begin every January 1 and July 1.

During the three months ended March 31, 2018, no shares of common stock were purchased under the 2017 ESPP. The fair value of common shares to be issued under the 2017 ESPP were calculated using the Black-Scholes-Merton option-pricing model with the following assumptions:



	Three Months Ended March 31, 2018

Expected life	0.5 years
Volatility	37.01%
Risk-free interest rate	1.61%
Dividend yield	—%
Weighted-average grant date fair value	$7.93

2017 Equity Incentive Plan—The Company's 2017 Equity Incentive Plan ("2017 EIP") became effective on July 26, 2017, and provides for the issuance of incentive and nonqualified common stock options and restricted stock units to employees, directors, officers, and consultants of the Company. The number of shares of common stock reserved for issuance under the 2017 EIP is 7,895,659. The number of shares reserved for issuance under the 2017 EIP will increase automatically on January 1 of each calendar year beginning on January 1, 2018 and continuing through January 1, 2028, by the number of shares equal to the lesser of 5% of the total outstanding shares of the Company's common stock as of the immediately preceding December 31 or an amount determined by the board of directors. On December 22, 2017, the board of directors determined that there would be no increase to the number of shares reserved for issuance under the 2017 EIP on January 1, 2018. The term of each restricted stock unit under the plan shall be no more than 10 years and generally vest over a four-year period. The term of each option grant shall be no more than 10 years and generally vest over a four-year period.

Amended and Restated 2004 Equity Incentive Plan-The Company granted options under its Amended and Restated 2004 Equity Incentive Plan, as amended (“2004 Plan”), until July 26, 2017, when the plan was terminated in connection with the Company’s IPO. Accordingly, no shares are available for future issuance under this plan. The 2004 Plan continues to govern outstanding equity awards granted thereunder.

Options to Purchase Common Stock—The Company did not issue any options to purchase common stock during the three months ended March 31, 2018. The fair value of the options issued under the Amended and Restated 2004 Equity Incentive Plan for the three months ended March 31, 2017 were calculated using the Black-Scholes-Merton option-pricing model with the following assumptions:



	Three Months Ended March 31, 2017

Expected life	7 years
Volatility	37.88%
Risk-free interest rate	2.26%
Dividend yield	—%
Weighted-average grant date fair value	4.53

The following table presents information regarding options granted, exercised, forfeited, or canceled for the periods presented:



	Number Of Options	Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Life (years)	Aggregate Intrinsic Value

Outstanding at December 31, 2017	13,180,950	$	6.30	7.02	$	329,786
Options granted	—	—
Options exercised	(1,198,732)	5.01			21,365
Options forfeited or canceled	(161,194)	9.05
Outstanding at March 31, 2018	11,821,024	6.39		6.80	194,319
Options exercisable at March 31, 2018	8,101,710	$	5.18	6.09	$	143,034

The fair value of the outstanding options to purchase common stock will be recorded as stock-based compensation over the vesting period. As of March 31, 2018, there was $15,256 of total unrecognized compensation cost related to options to purchase common stock, which is expected to be recognized over a weighted-average period of 2.12 years.

Restricted Stock Units—The following table summarizes activity for restricted stock units for the three months ended March 31, 2018:



	Restricted Stock Units		Weighted Average Grant-Date Fair Value

Unvested outstanding at December 31, 2017	981,276		$	22.78
Granted	216,312		20.58
Vested	(7,532	)	22.78
Forfeited or canceled	(37,338	)	22.74
Unvested outstanding at March 31, 2018	1,152,718		$	22.37

The fair value of the outstanding restricted stock units will be recorded as stock-based compensation over the vesting period. As of March 31, 2018, there was $23,995 of total unrecognized compensation cost related to restricted stock units, which is expected to be recognized over a weighted-average period of 3.57 years.

Compensation Cost—The following table presents detail of stock-based compensation, net of the amount capitalized in internally developed software, included in the Company’s condensed consolidated statements of operations for the periods indicated below



	Three Months Ended March 31,
	2018		2017

Cost of revenue	$	1,300	$	714
Technology and development	1,473		731
Marketing	119		119
General and administrative	1,304		1,117
Total stock-based compensation	$	4,196	$	2,681