Stockholders' Equity (Deficit) (Tables)

12 Months Ended

Dec. 31, 2021

Equity [Abstract]

Summary of Stock Options Valuation Assumptions

The following table summarizes the weighted-average grant date value of options and the assumptions used to develop their fair value.

	Year ended December 31,
	2021		2020		2019
Weighted-average grant date fair value of options	$	30.71	$	7.01	$	1.20
Risk-free interest rate	0.96%—1.08%		0.34%—0.84%		1.51%—2.53%
Expected volatility	54.41%—56.25%		49.64%—51.49%		46.70%—47.87%
Expected life in years	6.02—6.06 years		5.49—6.10 years		5.52—6.08 years
Dividend yield		—		—		—

Summary of Changes in Stock Options Activity

A summary of the changes in common stock options issued under all of the existing stock option plans is as follows:

(in thousands, except per share amounts)	Shares			Weighted average of exercise prices		Weighted average of remaining term (years)		Aggregate intrinsic value
Options outstanding at December 31, 2019		9,327		$	2.22		8.17	$	65,294
Granted		1,384			14.85		—		—
Exercised		(2,053	)		2.25		—		—
Forfeited		(443	)		5.33		—		—
Options outstanding at December 31, 2020		8,215		$	4.30		7.65	$	491,648
Granted		263			58.36		—		—
Exercised		(2,426	)		2.46		—		—
Forfeited		(324	)		11.22		—		—
Options outstanding at December 31, 2021		5,728		$	8.77		6.95	$	168,772
Vested and expected to vest at December 31, 2021(1)		5,490		$	6.71		6.91	$	164,384
Vested at December 31, 2021		3,629		$	3.53		6.46	$	116,440

(1) The expected-to-vest options are the result of applying the pre-vesting forfeiture rate to outstanding options.

Summary of RSU Table

The following table summarizes the RSU activity, including vesting of the performance-based restricted stock units below, under the Plans for the year ending December 31, 2021:

(in thousands, except per share amounts)	Shares			Weighted average grant date fair value
Nonvested at December 31, 2019		—		$	—
Granted		1,408			24.67
Vested		—			—
Cancelled/Forfeited/Expired		—			—
Nonvested at December 31, 2020		1,408		$	24.67
Granted		1,548			57.19
Vested		(350	)		24.07
Cancelled/Forfeited/Expired		(234	)		42.97
Nonvested at December 31, 2021		2,372		$	44.10

Summary of Stock-Based Compensation Expense

          Total stock-based compensation expense recognized was as follows:

	Year ended December 31,
(in thousands)	2021		2020		2019
Cost of revenue	$	2,055	$	769	$	191
Sales and marketing		7,761		3,310		838
Research and development		5,901		2,500		666
General and administrative		9,707		4,479		1,461
Total stock-based compensation expense	$	25,424	$	11,058	$	3,156