Stock-based Compensation:

2017 Employee Stock Purchase Plan—The Company’s 2017 Employee Stock Purchase Plan (“2017 ESPP”) was approved by the board of directors 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 each purchase date, eligible employees will 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. No shares of common stock have been purchased under the 2017 ESPP as the initial offering period has yet to commence.

2004 Equity Incentive Plan—The Company granted options under its 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. The term of each option under the plan shall be no more than 10 years and generally vest over a four-year period.

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 7,859,659. 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 and option 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.

Black-Scholes-Merton option-pricing model—The grant-date fair value of each option award is estimated on the date of grant using the Black-Scholes-Merton option-pricing model. The inputs used below are subjective and generally require significant analysis and judgment to develop. The Company has not declared or paid any cash dividends and does not currently expect to do so in the future. The risk-free interest rate used in the Black-Scholes-Merton option-pricing model is based on the implied yield currently available in U.S. Treasury securities at maturity with an equivalent term. Expected volatility is based on an average volatility of stock prices for a group of real estate and technology industry peers. The Company uses the “simplified method” to calculate expected life due to the lack of historical exercise data, which assumes a ratable rate of exercise over the contractual life to estimate the expected term for employee options. The expected term of options represents the period that the stock-based awards are expected to be outstanding for the remaining unexercised shares. The Company accounts for forfeitures as they occur. The range of assumptions for the years ended December 31, 2015, 2016, and 2017, are provided in the following table.



	Year End December 31,
	2015	2016	2017

Expected life	7 years	7 years	7 years
Volatility	42.51%-49.62%	38.15%-41.36%	37.88%-40.97%
Risk-free interest rate	1.71%-2.01%	1.39%-2.32%	1.96%-2.26%
Dividend yield	—%	—%	—%
Weighted-average grant date fair value	$3.99	$4.11	$4.86

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



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

Outstanding at January 1, 2017	13,291,684		$	5.85	7.74	$	61,774
Options granted	1,137,046		10.78
Options exercised	(744,215	)	4.03			20,308
Options forfeited or canceled	(503,565	)	7.95
Outstanding at December 31, 2017	13,180,950		6.30		7.02	329,786
Options exercisable at December 31, 2017	8,754,523		4.94		6.25	230,914

The total grant date fair value of shares vested during 2015, 2016, and 2017 was $4,917, $9,817, $10,571, respectively. The total grant date fair value of shares exercised during 2015, 2016, and 2017 was $1,373, $911, and $3,002, respectively.

There was $18,187 of total unrecognized stock-based compensation related to non-vested stock option arrangements granted under the 2004 Plan as of December 31, 2017. These costs are expected to be recognized over a weighted-average period of 2.30 years. The total fair value of options vested was $71,592 and $274,192 as of December 31, 2016 and December 31, 2017, respectively.

The following table summarizes activity for restricted stock units for the year ended December 31, 2017:



	Restricted Stock Units		Weighted Average Grant-Date Fair Value

Unvested outstanding at January 1, 2017	—		$	—
Granted	981,929		22.78
Vested	—		—
Forfeited or canceled	(653	)	22.78
Unvested outstanding at December 31, 2017	981,276		$	22.78

The fair value of the outstanding restricted stock units will be recorded as stock-based compensation over the vesting period. As of December 31, 2017, there was $21,856 of total unrecognized compensation cost related to restricted stock units, which is expected to be recognized over a weighted-average period of 3.75 years. There were no restricted stock units authorized, issued, or outstanding as of December 31, 2016.

The following table presents the detail of stock-based compensation amounts included in the Company’s consolidated statements of operations for the periods indicated below:



	Year End December 31,
	2015		2016		2017

Cost of revenue	$	1,440	$	2,266	$	2,902
Technology and development	1,375		2,383		3,325
Marketing	298		469		487
General and administrative	2,449		3,295		4,387
Total stock-based compensation	$	5,562	$	8,413	$	11,101

Stock-based compensation of $772 is included in general and administrative expenses attributable to the tender offer that closed in August 2015. Existing investors acquired

1,593,409 shares of common stock at a premium of $2.16 per share over the fair value at the time of the tender offer. Of the 1,593,409 shares, 358,330 were purchased from employees and 1,235,079 were purchased from non-employees. The premium attributable to the shares tendered from non-employees in the amount of $2,659 was treated as an in-substance dividend.

The Company capitalizes stock-based compensation related to work performed on internally developed software. There was $49, $100, and $268 of stock-based compensation that was capitalized in the years ended 2015, 2016, and 2017, respectively. All stock-based compensation is related to employees in technology and development.