Stock-Based Compensation

9 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

Stock-Based Compensation Expense

Stock-based compensation expense was recorded in the following cost and expense categories consistent with the respective employee or service provider’s related cash compensation (in thousands):


	Three months ended September 30,				Nine months ended September 30,
	2021		2020		2021		2020
Cost of revenue
Subscription and support	$	731	$	426	$	1,824	$	1,293
Professional services	407		272		1,183		1,062
Operating expenses
Research and development	2,347		2,167		7,195		5,790
Sales and marketing	4,095		2,687		10,481		8,367
General and administrative	5,107		5,049		14,679		18,919
Total	$	12,687	$	10,601	$	35,362	$	35,431

Stock Options

The following table summarizes the option activity under the Plans for the nine months ended September 30, 2021:


	Options	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)

Outstanding at December 31, 2020	2,903,167	$	14.48	4.7
Granted	—	—
Forfeited	(6,380)	19.25
Exercised	(629,755)	13.96
Outstanding at September 30, 2021	2,267,032	$	14.61	4.1

Exercisable at September 30, 2021	2,259,753	$	14.59	4.1

Restricted Stock Units

The following table summarizes the restricted stock unit activity under the Plan for the nine months ended September 30, 2021:


	Number of Shares	Weighted- Average Grant Date Fair Value

Unvested at December 31, 2020	2,904,616	$	35.72
Granted	872,135	108.00
Forfeited	(182,761)	63.62
Vested(1)	(1,557,830)	30.63
Unvested at September 30, 2021	2,036,160	$	68.96

(1) During the nine months ended September 30, 2021, in accordance with our Nonqualified Deferred Compensation Plan, recipients of 402,832 shares had elected to defer settlement of the vested restricted stock units and 270,567 shares were released from deferral. This resulted in total deferred units of 695,869 as of September 30, 2021.

Employee Stock Purchase Plan

During the nine months ended September 30, 2021, 148,864 shares of common stock were purchased under the ESPP at a weighted-average price of $59.52 per share, resulting in cash proceeds of $8.9 million.

Compensation expense associated with ESPP purchase rights is recognized on a straight-line basis over the vesting period. At September 30, 2021, there was approximately $1.0 million of total unrecognized compensation expense related to the ESPP, which is expected to be recognized over a weighted-average period of 0.3 years.