Preferred Stock—As of September 30, 2022 and December 31, 2021, our amended and restated certificate of incorporation authorized us to issue 10,000,000 shares of preferred stock with a par value of $0.001 per share.

Amended and Restated 2004 Equity Incentive Plan—We granted options under our 2004 Equity Incentive Plan, as amended (our "2004 Plan"), until July 26, 2017, when we terminated it in connection with our initial public offering. Accordingly, no shares are available for future issuance under our 2004 Plan. Our 2004 Plan continues to govern outstanding equity awards granted thereunder. The term of each stock option under the plan is no more than 10 years, and each stock option generally vests over a four-year period.

2017 Equity Incentive Plan—Our 2017 Equity Incentive Plan (our "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, and consultants. The number of shares of common stock initially reserved for issuance under our 2017 EIP was 7,898,159. The number of shares reserved for issuance under our 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 our common stock as of the immediately preceding December 31 or an amount determined by our board of directors. The term of each stock option and restricted stock unit under the plan will not exceed 10 years, and each award generally vests between two and four years.


	September 30, 2022	December 31, 2021
Stock options issued and outstanding	3,309,305	4,019,011
Restricted stock units outstanding	11,322,125	4,617,425
Shares available for future equity grants	12,774,103	15,205,854
Total shares reserved for future issuance	27,405,533	23,842,290

2017 Employee Stock Purchase Plan—Our 2017 Employee Stock Purchase Plan (our "ESPP") was approved by our board of directors on July 27, 2017 and enables eligible employees to purchase shares of our common stock at a discount. Purchases will be accomplished through participation in discrete offering periods. We initially reserved 1,600,000 shares of common stock for issuance under our ESPP. The number of shares reserved for issuance under our 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 our common stock as of the immediately preceding December 31 or an amount determined by our board of directors. On each purchase date, eligible employees will purchase our common stock at a price per share equal to 85% of the lesser of (i) the fair market value of our common stock on the first trading day of the offering period and (ii) the fair market value of our common stock on the purchase date.


	Nine Months Ended September 30, 2022	Year Ended December 31, 2021
Shares available for issuance at beginning of period	4,768,506	4,039,667
Shares issued during the period	(661,054)	(334,248)
Total shares available for future issuance at end of period	4,107,452	3,705,419


	Number of Options	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
Outstanding as of January 1, 2022(1)	4,019,011	$	8.02	3.73	$	122,038
PSOs earned(1)	150,000	27.50
Options exercised	(695,705)	6.96

Options expired	(164,001)	9.06
Outstanding as of September 30, 2022	3,309,305	9.08		3.18	2,405
Options exercisable as of September 30, 2022	3,309,305	9.08		3.18	2,405

(1) We granted stock options subject to performance conditions (“PSOs”) to our chief executive officer in 2019. We previously reported the target achievement level of these PSOs - 150,000 PSOs - within our outstanding stock options. During the first quarter of 2022, our board of directors determined that our chief executive officer earned his PSOs at the maximum achievement level. Accordingly, we are reporting an additional 150,000 PSOs as being earned during the first quarter of 2022.

The grant date fair value of our stock options was recorded as stock-based compensation over the stock options' vesting period. All outstanding options were fully vested as of September 30, 2022. We did not recognize any option-related expense during the nine months ended September 30, 2022. With respect to our PSOs, we had previously expensed the PSOs based on their maximum achievement level. During the first quarter of 2022, our board of directors certified our maximum achievement of the PSOs.


	Restricted Stock Units	Weighted-Average Grant-Date Fair Value
Outstanding as of January 1, 2022	4,617,425	$	37.13
Granted	9,866,403	10.53
Vested	(1,362,071)	28.05
Forfeited or canceled	(1,799,632)	25.94
Outstanding or deferred as of September 30, 2022(1)	11,322,125	16.82

(1) Starting with the restricted stock units granted to them in June 2019, our non-employee directors have the option to defer the issuance of common stock receivable upon vesting of such restricted stock units until 60 days following the day they are no longer providing services to us or, if earlier, upon a change in control transaction. The amount reported as vested excludes restricted stock units that have vested but whose settlement into shares has been deferred. The amount reported as outstanding or deferred as of September 30, 2022 includes these restricted stock units. As no further conditions exist to prevent the issuance of the shares of common stock underlying these restricted stock units, the shares are included in basic and diluted weighted shares outstanding used to calculate net loss per share attributable to common stock. The amount of shares whose issuance have been deferred is not considered material and is not reported separately from stock-based compensation in our consolidated statements of changes in mezzanine equity and stockholders’ equity.

The grant date fair value of restricted stock units is recorded as stock-based compensation over the vesting period. As of September 30, 2022, there was $153,216 of total unrecognized compensation cost related to restricted stock units, which is expected to be recognized over a weighted-average period of 3.11 years.

As of September 30, 2022, there were 1,119,236 restricted stock units subject to performance and market conditions ("PSUs") at 100% of the target level. Depending on our achievement of the performance and market conditions, the actual number of shares of common stock issuable upon vesting of PSUs will range from 0% to 200% of the target amount. For each PSU recipient, the awards will vest only if the recipient is continuing to provide service to us upon our board of directors, or its compensation committee, certifying that we have achieved the PSU's related performance or market conditions. Stock-based compensation expense for PSUs with performance conditions is recognized when it is probable that the performance conditions will be achieved. For PSUs with market conditions, the market condition is reflected in the grant-date fair value of the award and the expense is recognized over the life of the award. Stock-based compensation expense associated with the PSUs is as follows:


	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
PSU expense	$	1,867	$	1,844	$	3,536	$	4,465
Expense due to reassessment of achievement related to prior periods	(815)		—		(815)		—
Total expense	$	1,052	$	1,844	$	2,721	$	4,465

Compensation Cost—The following table details, for each period indicated, our stock-based compensation, net of forfeitures, and the amount capitalized in website and software development costs, each as included in our consolidated statements of comprehensive loss:


	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
Cost of revenue	$	4,387	$	3,283	$	11,644	$	10,019
Technology and development(1)	7,371		5,455		23,036		16,987
Marketing	1,028		537		3,024		1,615
General and administrative	5,284		3,835		13,968		10,817
Total stock-based compensation	$	18,070	$	13,110	$	51,672	$	39,438