Stock-Based Plans

3 Months Ended

Mar. 31, 2022

Share-based Payment Arrangement [Abstract]

Our board of directors sets the terms, conditions, and restrictions related to our 2017 Employee Stock Purchase Plan (ESPP) and the grant of stock options, restricted stock units (RSUs) and performance-based awards under our equity incentive plans. Our board of directors determines the number of awards to grant and also sets vesting criteria.

In general, RSUs vest on a quarterly basis over a period of four years from the date of grant at a rate of 25% on the first anniversary of the grant date and ratably each quarter over the remaining 12 quarters, or ratably over 16 quarters, subject to the employees’ continued employment. We may grant RSUs with different vesting terms from time to time. In the first quarter of 2022, we granted 0.8 million of retention RSUs which vest within one year.

Incentive stock options and non-statutory stock options granted under our 2011 Equity Incentive Plan (2011 Plan) have a term of no more than ten years from the date of grant and an exercise price of at least 100% of the fair market value of the underlying common stock on the date of grant. Generally, options vest at a rate of either 25% on the first anniversary of the option grant date and ratably each month over the remaining period of 36 months, or ratably each month over 48 months. We may grant options with different vesting terms from time to time.

For performance-based share awards, our board of directors sets the performance objectives and other vesting provisions in determining the number of shares or value of performance units and performance shares that will be paid out. Such payout will be a function of the extent to which performance objectives or other vesting provisions have been achieved.

2011 Equity Incentive Plan

In January 2011, our board of directors adopted the 2011 Plan under which incentive stock options, non-statutory stock options, RSUs, stock appreciation rights, performance stock units (PSUs), and performance shares may be granted to our employees, directors, and consultants. In April 2019, our board of directors authorized, and in June 2019, our stockholders approved an amendment and restatement of the 2011 Plan to make various changes, including increasing the number of shares reserved for issuance by approximately 5.0 million shares and extending the term of the 2011 Plan until April 2029. In May 2020, our board of directors authorized, and in June 2020, our stockholders approved, an increase of 1.4 million shares reserved for issuance under the 2011 Plan. In April 2021, our board of directors authorized, and in May 2021, our stockholders approved, an additional increase of 4.1 million shares reserved for issuance under the 2011 Plan.

Activity under the various plans was as follows:

Restricted Stock Units:


	Number of Units (in 000s)	Weighted-Average Grant Date Fair Value per Unit
Balance at December 31, 2021	5,141	$	5.18
RSU granted	808	$	3.62
RSU released	(302)	$	5.40
RSU forfeited	(70)	$	5.30
Balance at March 31, 2022	5,577	$	4.94

As of March 31, 2022, the unrecognized compensation costs related to outstanding unvested RSUs under our equity incentive plans were $21.8 million. We expect to recognize those costs over a weighted average period of 2.2 years.

Stock Options:


	Number of Options (000s)	Weighted-Average Exercise Price per Option		Weighted- Average Remaining Contractual Life (in Years)	Aggregate Intrinsic Value (1) in (000s)
Balance at December 31, 2021	1,597	$	7.08	5.6	$	82
Options granted	—	$	—		$	—
Options exercised	(8)	$	2.63		$	7
Options forfeited	(47)	$	14.84		$	—
Balance as of March 31, 2022	1,542	$	6.87	5.6	$	35
Vested at March 31, 2022	1,469	$	6.89	5.4	$	35
Unvested awards at March 31, 2022	73	$	6.34	8.4	$	—

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(1)Aggregate intrinsic value as of March 31, 2022 was calculated as the difference between the closing price per share of our common stock on the last trading day of March 31, 2022, which was $3.59, and the exercise price of the options, multiplied by the number of in-the-money options.

As of March 31, 2022, the unrecognized compensation costs related to outstanding unvested options under our equity incentive plans were $0.1 million. We expect to recognize those costs over a weighted average period of 0.5 years.

Performance-based Awards:

Performance Stock Units with Market Condition

We have granted PSU awards to certain executive officers and senior level employees. The number of PSUs ultimately earned under these awards is calculated based on the Total Shareholder Return (TSR) of our common stock as compared to the TSR of a defined group of peer companies during the applicable three-year performance period. The percentage of PSUs that vest will depend on our relative position at the end of the performance period and can range from 0% to 200% of the number of units granted.

Based on the performance of our stock relative to our defined group of peer companies, none of the PSUs awarded in 2019 for the 2019-2021 measurement period were vested. The performance adjustment in the table below reflects that no shares were issued upon vesting of the 2019 PSU awards.

Activity under the TSR-based PSUs is as follows:


	Number of Units (in 000s)	Weighted-Average Grant Date Fair Value per Unit
Balance at December 31, 2021	1,210	$	10.11
PSU granted	—	$	—
Performance adjustment for 2019 awards	(341)	$	16.97
PSU released	—	$	—
PSU forfeited	—	$	—
Balance at March 31, 2022	869	$	7.00

As of March 31, 2022, the unrecognized compensation costs related to these awards were $3.2 million. We expect to recognize those costs over a weighted average period of 1.6 years.

Performance Stock Units with Performance Conditions

During 2019, we granted performance stock units to an employee. The number of performance stock units that ultimately vested under these awards was dependent on the employee achieving certain discrete operational milestones, the last of which was measured at December 31, 2021. In early 2022, it was determined that the operational milestones were not met and the 29 thousand awards that were outstanding on December 31, 2021 were cancelled.

2017 Employee Stock Purchase Plan (ESPP)

Our ESPP offers U.S. and some non-U.S. employees the right to purchase shares of our common stock. Our ESPP program has a six-month offering period, with a new period commencing on the first trading day on or after May 31 and November 30 of each year. Employees are eligible to participate through payroll deductions of up to 10% of their compensation. Employees may not purchase more than $25 thousand of stock for any calendar year. The purchase price at which shares are sold under the ESPP is 85% of the lower of the fair market value of a share of our common stock on the first day of the offering period or the last day of the offering period.

Stock-based Compensation Expense

Total stock-based compensation expense recognized was as follows (in thousands):


	Three Months Ended March 31,
	2022		2021
Restricted stock units, stock options and performance share units	$	3,942	$	3,473
Employee stock purchase plan	100		204
Total stock-based compensation	$	4,042	$	3,677