Stock-Based Compensation

2009 Equity Incentive Plan

The Company’s Board of Directors (the Board) adopted the 2009 Equity Incentive Plan (as amended to date, the Plan) effective September 3, 2009. The Plan is intended to further align the interests of the Company and its stockholders with its employees, including its officers, non-employee directors, consultants and advisers by providing equity-based incentives. The Plan allows for the issuance of up to 2,533,333 shares of the Company’s common stock. In addition, as of March 31, 2018 there were 8,334 options outstanding that were issued outside the Plan to consultants in 2013.

The types of awards that may be granted under the Plan include options (both non-qualified stock options and incentive stock options), stock appreciation rights, stock awards, stock units and other stock-based awards. The term of each award is determined by the Compensation Committee of the Board at the time each award is granted, provided that the term of the option does not exceed ten years. Vesting schedules for stock options vary, but generally vest 25% per year, over four years for employee options and on the one year anniversary date for non-employee director options. The Plan had 1,187,558 shares available for future grants as of March 31, 2018.

Accounting for Stock-Based Compensation

The Company recognizes non-cash compensation expense for stock-based awards based on their grant date fair value, determined using the Black-Scholes option-pricing model. During the three months ended March 31, 2018 and 2017, the weighted average fair market value for options granted was and $0.52 and $1.69, respectively.

Total stock-based compensation expense recognized using the straight-line attribution method and included in operating expenses in the Condensed Consolidated Statements of Operations was approximately $0.1 million and ($0.1) million for the three months ended March 31, 2018 and 2017, respectively.

Assumptions Used In Determining Fair Value of Stock Options

Inherent in the Black-Scholes option-pricing model are the following assumptions:

Volatility. The Company estimates stock price volatility based on the Company’s historical stock price performance over a period of time that matches the expected term of the stock options.

Risk-free interest rate. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant commensurate with the expected term assumption.

Expected term. The expected term of stock options granted is based on an estimate of when options will be exercised in the future. The Company applied the simplified method of estimating the expected term of the options, described in the SEC’s Staff Accounting Bulletins 107 and 110, as the historical experience is not indicative of expected behavior in the future. The expected term, calculated under the simplified method, is applied to groups of stock options that have similar contractual terms. Using this method, the expected term is determined using the average of the vesting period and the contractual life of the stock options granted.

Dividend rate. The dividend rate is based on the historical rate, which the Company anticipates will remain at zero.

Forfeitures. The Company accounts for forfeitures when they occur. Ultimately, the actual expense recognized over the vesting period will be for only those shares that vest.

The fair market value of these stock options at the date of grant was estimated using the Black-Scholes option-pricing model with the following weighted average assumptions for the three months ended:



	March 31, 2018		March 31, 2017
Expected term	6 years, 3 months		6 years, 3 months
Interest rate	2.47	%	2.17	%
Dividend rate	—		—
Volatility	87.7	%	89.3	%

Stock Option Activity

The following table summarizes stock option activity for the three months ended March 31, 2018:



	Number of shares		Weighted- average exercise price		Weighted- average remaining contractual term	Aggregate intrinsic value
Outstanding at December 31, 2017	1,089,513		$	12.06	7 years, 3 months	$	—
Granted	244,000		0.69		9 years, 10 months	—
Exercised	—		—
Forfeited	—		—
Expired	(822	)	6.24
Outstanding at March 31, 2018⁽¹⁾	1,332,691		$	9.98	7 years, 6 months	$	—
Exercisable at March 31, 2018	707,687		$	16.74	6 years	$	—


(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.

The total fair value of options vested during the three months ended March 31, 2018 was approximately $0.2 million. Additionally, as of March 31, 2018, there was approximately $0.9 million of unrecognized compensation expense related to non-vested stock options which is expected to be recognized over a weighted-average period of 2.1 years.