Stock-Based Compensation Expense (Tables)

3 Months Ended

Mar. 31, 2020

Share-based Payment Arrangement [Abstract]

Schedule of Stock-Based Compensation Expense

Stock-based compensation expense for restricted stock units, 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,
	2020		2019
	(in thousands)
Stock-based compensation expense:
Cost of revenue	$	931	$	573
Research and development	4,645		3,174
Sales and marketing	3,678		2,464
General and administrative	4,093		2,423
Total stock-based compensation expense	$	13,347	$	8,634

Summary of Restricted Stock and Restricted Stock Unit Activity

Restricted stock unit activity during the three months ended March 31, 2020 was as follows:

	Shares	Weighted-Average Grant Date Fair Value
Unvested balance as of December 31, 2019	2,936,924	$	32.43
Granted	1,181,721	59.96
Vested	(308,333)	25.87
Forfeited	(94,970)	33.72
Unvested balance as of March 31, 2020	3,715,342	$	41.71

Summary of Stock Option Activity

Stock option activity during the three months ended March 31, 2020 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, 2019	2,705,458	$	10.18
Granted	—	—
Exercised	(125,432)	12.50			$	4,519
Forfeited/cancelled	(11,250)	12.47
Outstanding as of March 31, 2020	2,568,776	$	10.06	4.8	$	85,461
Vested and exercisable as of March 31, 2020	2,255,925	$	9.34	4.6	$	76,671