As of September 30, 2021, the only equity compensation plans from which the Company may currently issue new awards are the Company’s 2013 Stock Incentive Plan (as amended to date, the “2013 Plan”) and 2017 Employee Stock Purchase Plan (as amended to date, the “2017 ESPP”), each as more fully described below.

The 2013 Plan allows for the issuance of incentive stock options intended to qualify under Section 422 of the Internal Revenue Code of 1986, as amended (the “Code”), non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock units (“RSUs”), other stock-based awards and performance awards. The total number of shares of common stock authorized for issuance under the 2013 Plan is 5,653,057 shares of the Company’s common stock, plus such additional number of shares of common stock (up to 868,372 shares) as is equal to the number of shares of common stock subject to awards granted under the Company’s 2005 Stock Incentive Plan or 2008 Stock Incentive Plan (the “2008 Plan”), to the extent such awards expire, terminate or are otherwise surrendered, canceled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right.

As of September 30, 2021, options to purchase a total of 4,796,063 shares of common stock and 576,371 RSUs were outstanding and up to 93,469 shares of common stock remained available for grant under the 2013 Plan.

The Company has not made any awards pursuant to other equity incentive plans, including the 2008 Plan, since the Company’s stockholders approved the 2013 Plan. As of September 30, 2021, options to purchase a total of 207,908 shares of common stock were outstanding under the 2008 Plan. In addition, as of September 30, 2021, non-statutory stock options to purchase an aggregate of 325,000 shares of common stock were outstanding. These options were issued outside of the 2013 Plan to certain newly-hired employees in 2015 and 2014 pursuant to the Nasdaq inducement grant exception as a material component of such new hires’ employment compensation.

The 2017 ESPP is intended to qualify as an "employee stock purchase plan" as defined in Section 423 of the Code. The total number of shares of common stock authorized for issuance under the 2017 ESPP is 412,500 shares of common stock, subject to adjustment as described in the 2017 ESPP. As of September 30, 2021, 216,326 shares remained available for issuance under the 2017 ESPP.

For the nine months ended September 30, 2021 and 2020, the Company issued 29,016 and 59,319 shares of common stock, respectively, under the 2017 ESPP and received proceeds of less than $0.1 million during each period, as a result of employee stock purchases.

The Company recognizes non-cash compensation expense for stock-based awards under the Company’s equity incentive plans and employee stock purchases under the Company’s 2017 ESPP as follows:

Total stock-based compensation expense attributable to stock-based awards made to employees and directors and employee stock purchases included in operating expenses in the Company's condensed statements of operations for the three and nine months ended September 30, 2021 and 2020 were as follows:

During the nine months ended September 30, 2021 and 2020, the weighted average fair market value of stock options granted was $1.54 and $1.25, respectively.

The following weighted average assumptions apply to the options to purchase 1,356,700 and 1,215,382 shares of common stock granted to employees and directors during the three and nine months ended September 30, 2021 and 2020, respectively:

All options granted during the nine months ended September 30, 2021 and 2020 were granted at exercise prices equal to the fair market value of the common stock on the dates of grant. As further described below, the vesting of certain options granted to employees were accelerated during the nine months ended September 30, 2021.

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

(1)

Includes both vested stock options as well as unvested stock options for which the requisite service period has not been rendered but that are expected to vest based on achievement of a service condition.

During the three months ended March 31, 2021, the Company accelerated the vesting of 1,535,578 options, which were previously granted from 2019 through 2021. As of September 30, 2021, there was $1.6 million of unrecognized compensation cost related to unvested options, which the Company expects to recognize over a weighted average period of 2.1 years.

Restricted Stock Activity

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


	Time-based Awards			Market/Performance-based Awards
($ in thousands, except per share data)	Number of Shares	Weighted-Average Grant Date Fair Value		Number of Shares	Weighted-Average Grant Date Fair Value
Nonvested shares at December 31, 2020	354,003	$	2.27	549,318	$	1.54
Granted	—		—	—		—
Forfeited	(48,563)		2.31	(41,622)		1.54
Vested	(236,765)		2.25	—		—
Nonvested shares at September 30, 2021	68,675	$	2.30	507,696	$	1.54

Time-Based Restricted Stock Units

During the three months ended March 31, 2021, the Company accelerated the vesting of 137,872 unvested time-based restricted stock units which were previously granted in 2019 and 2020. During the nine months ended September 30, 2021, the Company recognized $0.1 million of compensation expense related to these awards. As of September 30, 2021, there was $0.1 million of unrecognized compensation cost for the time-based component of these awards, which is expected to be recognized over a weighted-average period of 1.8 years.

Market/Performance-Based Restricted Stock Units

In July 2020, the Company granted RSUs to certain employees, including executive officers, under the 2013 Plan, with vesting that may occur upon a combination of specific performance and/or market conditions. Accordingly, the Company views these RSUs as two separate awards: (i) an award that vests if the market condition is achieved, and (ii) an award that vests whether or not the market condition is achieved, so long as the performance condition is achieved.

The Company is currently recognizing compensation expense for these awards over the estimated requisite service period of 2.36 years based on the estimated fair value when considering the market condition of the award, which was determined using a Monte Carlo simulation. During the nine months ended September 30, 2021, the Company recognized $0.1 million of compensation expense related to these awards. As of September

30, 2021, the remaining unrecognized compensation cost for the market-based component of these awards, which is expected to be recognized over a weighted-average period of 1.2 years, is $0.5 million. In addition, should the performance condition be achieved, the Company would recognize an additional $0.3 million of compensation expense.