Stock-Based Compensation Expense (Tables)

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Stock-Based Compensation Expense

Stock-based compensation expense for restricted stock units (RSUs), performance-based restricted stock units (PSUs), stock options and issuances of common stock pursuant to our employee stock purchase plan was classified in the accompanying consolidated statements of operations as follows:

	Three Months Ended March 31,
	2021		2020
	(in thousands)
Stock-based compensation expense:
Cost of revenue	$	1,554	$	931
Research and development	7,815		4,645
Sales and marketing	5,746		3,678
General and administrative	5,747		4,093
Total stock-based compensation expense	$	20,862	$	13,347

Summary of Restricted Stock and Restricted Stock Unit Activity

RSUs and PSUs activity during the three months ended March 31, 2021 was as follows:

	Shares	Weighted-Average Grant Date Fair Value
Unvested balance as of December 31, 2020	2,941,914	$	45.86
Granted	1,447,632	88.64
Vested	(374,579)	33.20
Forfeited	(61,704)	52.67
Unvested balance as of March 31, 2021	3,953,263	$	62.61

Summary of Stock Option Activity

Stock option activity during the three months ended March 31, 2021 was as follows:

	Shares	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2020	1,933,013	$	10.07
Granted	—	—
Exercised	(170,006)	8.34			$	12,550
Forfeited/cancelled	—	—
Outstanding as of March 31, 2021	1,763,007	$	10.24	3.9	$	113,492
Vested and exercisable as of March 31, 2021	1,736,419	$	10.04	3.8	$	112,127