In August 2018, the 2018 Stock Option and Incentive Plan (2018 Plan) was adopted by the board of directors and approved by the stockholders and became effective in connection with the IPO. The 2018 Plan replaced the 2010 Stock Plan (2010 Plan) as the board of directors determined not to make additional awards under the 2010 Plan. The 2010 Plan will continue to govern outstanding equity awards granted thereunder.

The 2018 Plan allows for the granting of options, stock appreciation rights, restricted stock, restricted stock units (RSUs), unrestricted stock awards, performance-based restricted stock units (PSUs), dividend equivalent rights and cash-based awards. Every January 1, the number of shares of stock reserved and available for issuance under the 2018 Plan will cumulatively increase by five percent of the number of shares of Class A and Class B common stock outstanding on the immediately preceding December 31, or a lesser number of shares as approved by the board of directors.

As of September 30, 2022, there were 6,004,641 and 6,637,862 options issued and outstanding under the 2010 Plan and 2018 Plan, respectively (collectively, the Plans). As of September 30, 2022, 5,365,832 shares of Class A common stock and were available for grant under the 2018 Plan.

Stock options granted typically vest over a four-year period from the date of grant. Options awarded under the Plans are exercisable up to ten years.

Stock option activity for the nine months ended September 30, 2022 is presented below:


	Outstanding options	Weighted average exercise price	Weighted average remaining contractual term (years)	Aggregate intrinsic value (thousands)
Balance as of December 31, 2021	11,260,788	12.11	6.7	63,862
Granted	1,868,692	12.77
Exercised	(364,844)	8.30
Cancelled	(122,133)	16.76
Balance as of September 30, 2022	12,642,503	12.27	6.6	150
Vested and exercisable as of September 30, 2022	8,974,051	11.79	5.8	150
Vested and expected to vest as of September 30, 2022	12,437,571	12.25	6.6	150

The aggregate intrinsic value in the table above represents the difference between the fair value of common stock and the exercise price of outstanding, in-the-money stock options at September 30, 2022.

As of September 30, 2022, the total unrecognized stock-based compensation expense related to stock options outstanding was $24.0 million, which will be recognized over a weighted-average period of 2.4 years. The weighted-average fair value of stock options granted was $7.13 for the nine months ended September 30, 2022.

In July 2022, the Company awarded PSUs to certain senior executives, pursuant to the 2018 Plan. The awards vest based upon continued service and achievement of certain financial performance goals and market conditions established by the board of directors or Compensation Committee for a predetermined period.

For PSUs that vest based upon continued service and achievement of certain financial performance conditions, the grant date fair value is determined based upon the market closing price of our Class A common stock on the date of the grant. Compensation expense is recognized over the requisite service period if it is probable that the performance condition will be satisfied. The number of PSUs issued could range from 0% up to 200% of the target amount.

In addition, we have issued market-based PSUs that vest based upon continued service and achievement of certain market conditions. The estimated grant date fair value for market-based PSUs is determined using the Monte Carlo valuation model. We recognize compensation expense for such awards over the requisite service period using the accelerated attribution method.

Stock award activity, which includes PSUs, RSAs and PSUs, for the nine months ended September 30, 2022 is presented below:


	Outstanding RSUs, RSAs and PSUs	Weighted-average grant date fair value per share	Weighted average remaining contractual term (years)	Aggregate intrinsic value (thousands)
Balance as of December 31, 2021	4,353,637	18.40	1.5	75,873
Awarded (1)	8,123,233	11.17
Released	(1,457,254)	17.38
Cancelled	(1,238,528)	16.35
Balance as of September 30, 2022	9,781,088	12.84	1.8	59,469
Vested and expected to vest as of September 30, 2022	8,526,468	12.82	1.7	51,841

As of September 30, 2022, the total unrecognized stock-based compensation expense related to RSUs outstanding, including PSUs, was $98.4 million, which will be recognized over a weighted-average period of 3.1 years.

Stock-based compensation expense recognized in connection with stock options, RSUs, PSUs and the ESPP during each of the three and nine months ended September 30, 2022 and 2021 were as follows:


	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
Cost of net revenue	$	179	$	197	$	625	$	735
Product development	5,456		4,258		15,240		12,515
Sales, marketing and support	2,226		1,426		6,065		4,160
General and administrative	5,669		6,419		18,688		18,575
Total	$	13,530	$	12,300	$	40,618	$	35,985