Stock-Based Compensation and Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2022

Compensation Related Costs [Abstract]

Schedule of Weighted-Average Valuation Assumptions

We used the following weighted-average assumptions in applying the Black-Scholes valuation model for determination of option valuation for options granted for the year ended December 31, 2020:

	Year Ended December 31,
	2020
Risk-free interest rate	0.6%
Expected term (years)	6.6
Expected dividend yield	—
Expected volatility	71.0%

We used the following weighted-average assumptions in applying the Black-Scholes valuation model for determination of the 2018 ESPP share valuation:

	Years Ended December 31,
	2022	2021
Risk-free interest rate	3.1%-3.2%	0.1% - 2.8%
Expected term (years)	0.5 - 2.0	0.5 - 2.0
Expected dividend yield	—	—
Expected volatility	78.0%-88.9%	95.0% - 114.5%

Schedule of Employee and Non-Employee Stock-Based Compensation Expense

The following table summarizes the components of stock-based compensation expense in the consolidated statements of operations (in thousands):

	Years Ended December 31,
	2022		2021		2020
Cost of revenue	$	18,955	$	13,811	$	17,475
Research and development	33,956		20,274		19,037
Sales and marketing	18,651		17,085		10,997
General and administrative	42,404		24,962		26,384
	$	113,966	$	76,132	$	73,893

Schedule of Stock Option and RSU Activity

The following table summarizes the stock option activity under our stock plans during the reporting period:

	Outstanding Options
	Number of Shares	Weighted Average Exercise Price		Remaining Contractual Life (Years)	Aggregate Intrinsic Value
					(in thousands)
Balances at December 31, 2020	15,354,271	$	21.27
Exercised	(3,460,364)	23.05
Forfeited	(1,156,612)	16.33
Balances at December 31, 2021	10,737,295	21.23		5.2	$	60,304
Exercised	(537,324)	7.08
Forfeited	(42,774)	6.98
Expired	(1,408,888)	30.39
Balances at December 31, 2022	8,748,309	20.70		4.6	40,532
Vested and expected to vest at December 31, 2022	8,743,013	20.71		4.6	40,469
Exercisable at December 31, 2022	8,636,644	20.86		4.6	39,296

The following table presents the stock activity and the total number of shares available for grant under our stock plans:

	Plan Shares Available for Grant
Balances at December 31, 2020	20,233,754
Added to plan	8,102,014
Granted	(6,475,536)
Cancelled/Forfeited	2,778,276
Expired	(491,724)
Balances at December 31, 2021	24,146,784
Added to plan	8,384,460
Granted	(5,431,930)
Cancelled/Forfeited	2,597,990
Expired	(1,356,663)
Balances at December 31, 2022	28,340,641

Schedule of RSU Activity and Related Information

A summary of our stock awards activity and related information is as follows:

	Number of Awards Outstanding	Weighted Average Grant Date Fair Value
Unvested Balance at December 31, 2020	6,418,788	$	13.71
Granted	6,475,536	25.82
Vested	(2,904,996)	17.04
Forfeited	(1,621,664)	20.97
Unvested Balance at December 31, 2021	8,367,664	$	20.52
Granted	5,395,199	19.74
Vested	(2,957,215)	18.14
Forfeited	(1,256,613)	21.32
Unvested Balance at December 31, 2022	9,549,035	$	19.99