Stock Plans and Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Assumptions Used in Determining Fair Value of Shares Issuable

The fair value of shares issuable under the 2016 ESPP is determined using the Black-Scholes option pricing model with the following weighted-average assumptions:

	Year Ended December 31,
	2023	2022	2021
Employee Stock Purchase Plan:
Expected term (in years) (1)	0.50	0.50	0.50
Expected volatility (2)	50% - 60%	65% - 70%	45% - 60%
Risk-free interest rate (3)	5.18% - 5.51%	0.86% - 3.33%	0.05% - 0.06%
Dividend rate (4)	0%	0%	0%

(1)The expected term represents the contractual term of the 2016 ESPP;

(2)The expected volatility of the Company’s common stock on the date of grant is based on the weighted average of the Company’s historical volatility as a public company, the implied volatility of publicly-traded options on the Company’s common stock and the volatilities of publicly traded peer companies that are reasonably comparable to the Company’s own operations;

(3)The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for zero coupon U.S. Treasury notes with maturities approximately equal to the expected term of the grant; and

(4)The expected dividend yield is assumed to be zero as the Company has never paid dividends and has no current plans to pay any dividends on the Company’s common stock.

Schedule of Stock Option Activity

The following table summarizes the Company’s stock option activity:

	Stock options outstanding			Weighted average exercise price
Outstanding at December 31, 2022		142,202		$	23.89
Exercised		(75,457	)		17.48
Forfeited		(2,875	)		37.98
Outstanding at December 31, 2023		63,870			30.83

Schedule of Stock Options Outstanding, Vested and Expected to Vest and Exercisable

Stock options outstanding, vested and expected to vest and exercisable are as follows:

	As of December 31, 2023
	Number of shares		Remaining contractual life (years)		Weighted- average exercise price
Outstanding and exercisable		63,870		3.70	$	30.83

Summary of RSU and PSU Activity

The following table summarizes the Company’s RSU and PSU activity:

	Number of Shares
Outstanding at December 31, 2022		3,233,298
Granted		1,625,148
Vested		(1,123,677	)
Forfeited		(664,865	)
Outstanding at December 31, 2023		3,069,904

Schedule of Assumptions used in Monte Carlo Simulation Model

value of the market-based grants was determined using the Monte-Carlo simulation with the following assumptions:

	Year Ended December 31,
	2023	2022
Market-Based Grants:
Expected term (in years)	0.23 - 0.48	0.73 - 1.50
Expected volatility	51% - 57%	58% - 71%
Risk-free interest rate	4.88% - 5.35%	1.97% - 4.69%
Dividend rate	0%	0%

Summary of Stock-Based Compensation Expense

The Company recorded the total stock-based compensation expense as follows (in thousands):

	Year Ended December 31,
	2023		2022		2021
Cost of revenue	$	6,171	$	5,468	$	3,678
Sales and marketing		17,313		15,917		15,936
Research and development		12,225		9,967		8,717
General and administrative		13,180		16,268		15,764
Total	$	48,889	$	47,620	$	44,095