Stock-Based Compensation

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Stock-based compensation expense is included in the following line items in the condensed consolidated statements of operations (in thousands):


	Three Months Ended March 31,
	2021		2020
Sales and marketing	$	808	$	757
General and administrative	2,080		1,782
Research and development	5,000		3,819
Total stock-based compensation expense	$	7,888	$	6,358

The following table summarizes the components of non-cash stock-based compensation expense (in thousands):


	Three Months Ended March 31,
	2021		2020
Stock options and assumed options	$	617	$	801
Restricted stock units	7,224		5,510
Employee stock purchase plan	47		47
Total stock-based compensation expense	$	7,888	$	6,358
Tax windfall benefit from stock-based awards	$	2,560	$	578

We granted no stock options pursuant to our 2015 Equity Incentive Plan, or the 2015 Plan, during the three months ended March 31, 2021, as compared to an aggregate of 5,000 stock options for the same period in the prior year. There were 73,175 stock options exercised during the three months ended March 31, 2021, as compared to 63,748 stock options for the same period in the prior year. We granted an aggregate of 127,216 restricted stock units during the three months ended March 31, 2021, as compared to an aggregate of 100,728 restricted stock units for the same period in the prior year. There were 89,370 restricted stock units that vested during the three months ended March 31, 2021, as compared to 23,048 restricted stock units vested during the same period in the prior year.