Stock-based Compensation

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

2014 Equity Incentive Plan

In 2014, prior to the Merger, the Board of Directors and a majority of the stockholders adopted the 2014 Equity Incentive Plan, or the 2014 Plan, allowing for the issuance of 137 shares of common stock. The 2014 Plan has since been amended and restated with approval by the stockholders to increase the maximum number of shares issuable, as shown in the table below:


Original share pool			137
2015 increase			111
June 2017 increase			67
December 2017 increase (ratified in June 2018)			293
2019 increase			233
March 2020 increase			333
December 2020 increase			800
Total share authorized for grant as of December 31, 2021			1,974

As of December 31, 2021, the total shares authorized for grant under the 2014 Plan was 1,974, of which 587 were available for future grants.

Under the terms of the 2014 Plan, the Board of Directors may award stock options, restricted stock, restricted stock units, stock appreciation rights and dividend equivalent rights having either a fixed or variable price related to the fair market value of the shares and with an exercise or conversion privilege related to the passage of time, the occurrence of one or more events, or the satisfaction of performance criteria or other conditions or any other security with the value derived from the value of the shares.

Shares available for future grant under the 2014 Plan was as follows:


			Shares Available For Grant
Available as of December 31, 2020			1,113
Granted			(620)
Forfeited			71
Expired			23

Available as of December 31, 2021			587

Stock Options

The Board of Directors may grant stock options under the 2014 Plan at a price of not less than 100% of the fair market value of the Company’s common stock on the date the option is granted. The maximum term of an incentive stock option granted to participants may not exceed ten years. Subject to the limitations discussed above, the Board of Directors determines the term and exercise or purchase price of other awards granted under the 2014 Plan. The Board of Directors also determines the terms and conditions of awards, including the vesting schedule and any forfeiture provisions. Options granted under the 2014 Plan vest upon the passage of time, generally four years, or upon the attainment of certain performance criteria established by the Board of Directors. The Company may grant options to purchase common stock to non-employees for advisory and consulting services. Upon exercise of a stock option, the Company issues new shares of common stock.

A summary of the stock option activity during the year ended December 31, 2021 is presented below:


	Options Outstanding	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
Outstanding at beginning of year	529	$	31.62


Forfeited	(15)	$	8.65
Expired	(23)	$	27.01
Outstanding at end of year	491	$	32.53	6.41	$	—
Vested and expected to vest	491	$	32.53	6.41	$	—
Exercisable at year end	405	$	36.41	6.16	$	—

No stock options were exercised during the years ended December 31, 2021 and 2020.

As no stock options were granted during the year ended December 31, 2021, there was no related weighted-average grant date fair value. The weighted-average grant date fair value of stock options granted for the year ended December 31, 2020 was $4.42. The total grant date fair value of stock option vested during the years ended December 31, 2021 and 2020 was $1,194 and $1,900, respectively.

As of December 31, 2021, total unrecognized compensation cost related to unvested stock options was $936. This amount is expected to be recognized as stock-based compensation expense in the Company’s consolidated statements of operations and comprehensive loss over the remaining weighted average vesting period of 1.3 years.

The following table summarizes information about stock options outstanding as of December 31, 2021:


	Options Outstanding				Options Exercisable
Range of Exercise Prices	Number of Shares	Weighted-Average Remaining Contractual Life (Years)	Weighted Average Price		Number of Shares	Weighted Average Price
$5.55 - $9.15	187	7.9	$	7.84	127	$	7.34
$16.95 - $27.30	139	6.7	$	24.12	120	$	24.35
$27.45 - $54.15	93	6.2	$	35.49	85	$	35.48
$56.70 - $229.95	72	2.7	$	108.36	72	$	108.36
	491	6.4	$	32.53	405	$	36.41

The Company recognizes compensation expense using the straight-line method over the requisite service period. The share fair value of each stock option was determined on the date of grant using the Black-Scholes Model under the following assumptions:


	Years Ended December 31,
	2021	2020
Dividend yield	N/A	—
Risk-free interest rate	N/A	1.44% - 1.7%
Expected term (in years)	N/A	5.27 - 6.08
Volatility	N/A	100%-102%

N/A - No stock options were granted during the year ended December 31, 2021.

Restricted Stock Units

The Company issues time-based RSUs and PSUs to employees and non-employee service providers. Each RSU and PSU represents the right to receive one share of the Company’s common stock upon vesting and subsequent settlement. PSUs vest upon achievement of performance targets based on the Company's annual operating plan. The fair values of RSUs and PSUs are determined based on the closing price of the Company’s common stock on the date of grant.

Combined RSU and PSU activity for the year ended December 31, 2021 is summarized below:


	Number of Shares	Weighted Average Grant- Date Fair Value
Unvested as of January 1, 2021	143	$	6.21
Granted	620	$	5.70
Vested	(52)	$	6.25
Forfeited	(56)	$	7.69
Unvested as of December 31, 2021	655	$	5.63

The total grant-date fair value of RSUs and PSUs that vested during the year ended December 31, 2021 was $218. As of December 31, 2021, $2,790 of total unrecognized compensation expense related to unvested RSUs and PSUs was expected to be recognized over a weighted average period of 2.12 years.

Compensation Expense

Stock-based compensation is included in the consolidated statements of operations and comprehensive loss in general and administrative, research and development, or sales and marketing expenses, depending upon the nature of services provided. Stock-based compensation expense related to stock options, RSUs and PSUs granted to employees and non-employees was as follows:


	Years Ended December 31,
	2021		2020
Sales and marketing	$	450	$	476
Research and development	270		293
General and administrative	1,609		1,641
	$	2,329	$	2,410

Employee Stock Purchase Plan

The Company has an Employee Stock Purchase Plan, or ESPP. Under the ESPP, the Company has 500 shares of common stock reserved for issuance, subject to adjustment in the event of a stock split, stock dividend, combination or reclassification or similar event. The ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 25% of their eligible compensation, subject to any plan limitations. The ESPP provides for six-month offering periods. At the end of each offering period, employees can purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the last trading day of the offering period. As of December 31, 2021, the Company had not initiated employee enrollment to the plan.