Stock-based Compensation

Stock Options

The following table summarizes stock option activity for employees:

	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)		Aggregate Intrinsic Value

Outstanding at December 31, 2018		4,597,226		$	5.12		7.4	$	404
Granted		1,182,500		$	2.66
Exercised		-
Forfeited (1)		(2,606,289	)	$	2.79
Expired (1)		(2,400,590	)	$	6.51
Outstanding at September 30, 2019		772,847		$	4.89		7.3	$	-
Exercisable at September 30, 2019		476,390		$	6.13		6.4	$	-
Vested or expected to vest at September 30, 2019 (2)		772,847		$	4.89		7.3	$	-

_____________________

(

) Represents the number of options cancelled during the

nine

months ended

September 30, 2019

as a result of employees that were terminated due to the reduction in force.

(

) Represents the number of vested options at

September 30, 2019

plus the number of unvested options expected to vest based on the unvested options outstanding at

September 30, 2019.

Employee Stock Purchase Plan

The

2014

Employee Stock Purchase Plan (ESPP) initially authorized the issuance of up to

140,500

shares of Common Stock. The number of shares increases each

January 1,

commencing on

January 1, 2015

and ending on (and including)

January 1, 2024,

by an amount equal to the lesser of

one

percent of the outstanding shares as of the end of the immediately preceding fiscal year,

281,000

shares and any lower amount determined by the Company’s Board of Directors prior to each such

January

1st.

As of

September 30, 2019,

as a result of an increase on

January 1, 2019

one

percent of the outstanding shares as of the end of the fiscal year ending

December 31, 2018,

the

2014

ESPP authorized the issuance of up to

192,436

shares of Common Stock. The

tenth

offering under the

2014

ESPP began on

July 1, 2019

and ended on

September 30, 2019.

shares were issued during the

three

and

nine

months ended

September 30, 2019.

shares and

51,984

shares were issued during the

three

and

nine

months ended

September 30, 2018

under the

2014

ESPP. The Company incurred

zero

and

$68,000

in stock-based compensation expense related to the

2014

ESPP for the

three

and

nine

months ended

September 30, 2019

respectively. The Company incurred

$20,000

and

$0.1

million in stock-based compensation expense related to the

2014

ESPP for the

three

and

nine

months ended

September 30, 2018,

respectively.

Common Stock

The Company has the following shares of Common Stock reserved for future issuance:

	September 30,		December 31,
	2019		2018

Conversion of Series A Preferred Stock		21,771,032		22,112,775
Stock-based compensation awards		6,818,214		5,163,957
Employee Stock Purchase Plan		118,120		118,120
Total		28,707,366		27,394,852