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, 2017		2,681,072		$	7.18		6.8	$	121
Granted		2,041,600		$	2.61
Exercised		-
Forfeited		(83,433	)	$	5.82
Expired		(42,013	)	$	13.30
Outstanding at September 30, 2018		4,597,226		$	5.12		7.7	$	130
Exercisable at September 30, 2018		1,946,255		$	7.49		5.9	$	125
Vested or expected to vest at September 30, 2018 (1)		4,597,226		$	5.12		7.7	$	130

__________________________

(

) Represents the number of vested options at

September 30, 2018

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

September 30, 2018.

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.

The Company’s Board of Directors determined there was to be

increase on

January 1, 2018.

As of

September 30, 2018,

the

2014

ESPP authorized the issuance of up to

304,991

shares of Common Stock. The

seventh

offering under the

2014

ESPP began on

January 1, 2018

and ended on

June 30, 2018.

shares and

51,984

shares were issued during the

three

and

nine

months ended

September 30, 2018

under the

2014

ESPP. 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. The Company incurred

$18,000

and

$0.1

million in stock-based compensation expense related to the

2014

ESPP for the

three

and

nine

months ended

September 30, 2017,

respectively.

Common Stock

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

	September 30,		December 31,
	2018		2017

Conversion of Series A Preferred Stock		22,112,775		22,112,775
Stock-based compensation awards		5,038,511		3,572,457
Employee Stock Purchase Plan		140,479		192,463
Total		27,291,765		25,877,695