Stockholders' Equity and Stock-based Compensation Expense

9 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

Stockholders' Equity and Stock-based Compensation Expense

Stockholders’ Equity and Stock-based Compensation Expense

The Company’s equity incentive plans are broad-based, long-term programs intended to attract and retain talented employees and align stockholder and employee interests. In September 2021, stockholders approved an additional 450,000 shares for future grants. The 2019 Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock units (“RSUs”), performance stock units ("PSUs"), and other stock or cash awards.

The Company’s Board of Directors granted the Company's executive officers, senior management and certain employees 463,593 PSUs during the nine months ended September 30, 2021. Of this total, 198,591 units vest subject to the Company’s achievement of certain operational goals for the 2021 fiscal year related to product milestones, sales and commercial milestones and certain cost reduction targets. In addition, there is a service requirement related to half of the granted quantity that requires the grant recipient to provide one year of service subsequent to the milestone achievement date.

In July 2021, the Company granted 265,002 units to certain employees. This grant consists of four separate vesting quantities that will vest from April 2023 through June 2024 upon the achievement of milestones associated with each vesting quantity and continued service.

Activity under the Company's equity incentive plans is summarized as follows:

	Shares Available for Grant
Balance, December 31, 2020	1,085,170
Additional shares reserved	450,000
RSUs granted	(213,522)
PSUs granted	(463,593)
Options granted	(172,139)
Stock awards canceled / forfeited / expired	295,392
Options canceled / forfeited / expired	24,090
Balance, September 30, 2021	1,005,398

	Options Outstanding
	Number of Stock Options Outstanding	Weighted- Average Exercise Price		Weighted Average Remaining Term  (in Years)
Balance, December 31, 2020	217,007	$	22.35	3.75
Options granted	172,139	$	30.71
Options exercised	(57,498)	$	24.49
Options canceled / forfeited / expired	(24,090)	$	32.90
Balance, September 30, 2021	307,558	$	25.80	4.84

	Stock Awards Outstanding
	Number of Awards Outstanding	Weighted Average Grant Date Fair Value per Share
Balance, December 31, 2020	779,757	$	23.96
RSUs granted	213,522	$	36.80
PSUs granted	463,593	$	41.23
Awards released	(175,813)	$	22.45
Stock awards canceled / forfeited / expired	(298,028)	$	27.24
Balance, September 30, 2021	983,031	$	33.91

Stock-based Compensation Expense

Stock-based compensation expense by department recognized during the three and nine months ended September 30, 2021 and 2020 was as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Cost of revenue	$	330	$	326	$	908	$	1,359
Sales and marketing	711		648		1,954		2,618
Research and development	1,020		254		1,628		1,344
General and administrative	1,681		754		4,017		2,736
Total stock-based compensation expense	$	3,742	$	1,982	$	8,507	$	8,057