On February 26, 2022, the Company's board of directors authorized a share repurchase program to repurchase up to $200.0 million of the Company’s common stock in the open market or in privately negotiated transactions (through 10b5-1 trading plans or otherwise). The share repurchase program does not obligate the Company to acquire any particular amount of common stock and may be suspended at any time at the Company’s discretion, and the share repurchase program does not have an expiration date. The actual timing, number and value of shares repurchased is determined by management at its discretion and depends on a number of factors, including the market price of the Company’s stock, general business and market conditions, and other investment opportunities.

There were no share repurchases for the three months ended March 31, 2023. During the three months ended March 31, 2022, the Company repurchased approximately 2.4 million shares of common stock for approximately $36.4 million.

As of March 31, 2023, the Company’s remaining share repurchase authorization was approximately $116.5 million.

The Company sponsors the 2018 Equity Incentive Plan (the “2018 Plan”), which was approved by stockholders on September 5, 2018. The purpose of the 2018 Plan is to promote the long-term growth and profitability of the Company by (i) providing employees with incentives to improve stockholder value and to contribute to the growth and financial success of the Company through their future services, and (ii) enabling the Company to attract, retain

and reward the best available persons. The options granted under the 2018 Plan, may be granted at a price not less than the fair market value on the grant date.

The board of directors, or a committee of the board of directors, has granted options with an exercise price at fair value on the grant date. Grants of time-based awards generally vest over a four-year period for new hires and over a three-year period for subsequent grants to existing employees. Options expire as determined by the board of directors, or committee of the board of directors, but not more than ten years after the date of the grant.

As of March 31, 2023, 28,741,857 shares of common stock remain available for grant under the 2018 Plan.

The following is a summary of restricted stock units for the current year period:


	Restricted Stock Units
	Number of Shares			Weighted Average Grant-Date Fair Value		Weighted Average Remaining Contractual Term (in years)
Unvested at December 31, 2022		8,023,173		$	15.07		1.2
Granted		563,320		$	8.24
Vested		(979,131	)	$	17.52
Forfeited/cancelled		(896,761	)	$	14.56
Unvested at March 31, 2023		6,710,601		$	14.21		1.2

The following is a summary of stock option activity for the current year period:


	Stock Options
	Number of Shares			Weighted Average Exercise Price		Aggregate Intrinsic Value (in thousands)		Weighted Average Remaining Contractual Term (in years)
Outstanding at December 31, 2022		13,133,446		$	16.24	$	—		4.2
Granted		—		$	—
Exercised		—		$	—
Forfeited		(22,001	)	$	20.18
Expired		(2,325,356	)	$	16.61
Outstanding, vested and expected to vest at March 31, 2023		10,786,089		$	16.15	$	1,918		4.7
Vested and exercisable at March 31, 2023		8,770,544		$	16.59	$	—		4.7

The following is a summary of restricted stock awards for the current year period:


	Restricted Stock Awards
	Number of Shares			Weighted Average Grant-Date Fair Value		Weighted Average Remaining Contractual Term (in years)
Unvested at December 31, 2022		890,219		$	17.43		1.9
Granted		—		$	—
Vested		(80,905	)	$	17.38
Forfeited/cancelled		—		$	—
Unvested at March 31, 2023		809,314		$	17.43		1.8

The Company sponsors the 2018 Employee Stock Purchase Plan, as amended (the “ESPP”), which was approved by stockholders on September 5, 2018. The ESPP provides for 24-month offering periods beginning May 22 and November 22 of each year, and each offering period will consist of four six-month purchase periods, subject to a reset provision. On each purchase date, eligible employees will purchase the shares 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 offering date, or (2) the fair market value of its common stock on the purchase date.

As of March 31, 2023, 7,481,519 shares of common stock remain available for issuance under the ESPP.

Stock-based compensation expense recognized in the condensed consolidated financial statements is as follows:


	Three Months Ended March 31,
(in thousands)	2023		2022
Cost of revenue	$	1,241	$	1,409
Research and development		7,734		8,644
Sales and marketing		4,075		6,065
General and administrative		7,352		7,375
Restructuring		—		2,761
Stock-based compensation expense, net of amounts capitalized		20,402		26,254
Capitalized stock-based compensation expense		506		719
Stock-based compensation expense	$	20,908	$	26,973

As of March 31, 2023, unamortized stock-based compensation was as follows:


	Unrecognized stock-based compensation (in thousands)		Weighted average recognition period (in years)
Restricted stock units	$	86,935		2.0
Stock options		6,052		1.0
Restricted stock awards		8,407		1.8
ESPP		10,981		1.6
Total unrecognized stock-based compensation	$	112,375

In the United States, the Company offers its employees a defined contribution plan that qualifies as a deferred salary arrangement under Section 401 of the U.S. Internal Revenue Code (“401(k) Plan”). Under the 401(k) Plan, participating employees may defer a portion of their pretax earnings not to exceed the maximum amount allowed by the Internal Revenue Service. The Company currently provides a matching contribution of 25% of deferrals for eligible employees. Compensation expense for the Company's matching contributions was $1.7 million and $1.9 million during the three months ended March 31, 2023 and 2022, respectively.