G.	Stock-Based Compensation

The Company maintains a stock-based compensation plan (the “

Incentive Stock Plan”) that governs stock awards made to employees and directors prior to completion of the IPO.

November 2014,

the Board of Directors of the Company ("the Board"), and in

April 2015,

the Company’s stockholders, approved the Company’s

2014

Equity Incentive Plan (the

“2014

Plan”), which became effective in

April 2015.

The

2014

Plan provides for the grant of stock options, other forms of equity compensation, and performance cash awards. The maximum number of shares of common stock that

may

be issued under the

2014

Plan is

5,076,694

as of

March 31, 2019.

The number of shares of common stock reserved for issuance under the

2014

Plan will automatically increase on

January 1

of each year, beginning on

January 1, 2016,

and ending on and including

January 1, 2024,

of the total number of shares of the Company’s capital stock outstanding on

December 31

of the preceding calendar year, or a lesser number of shares determined by the Board. Pursuant to the terms of the

2014

Plan, on

January 1, 2019,

the common stock reserved for issuance under the

2014

Plan automatically increased by

1,058,214

shares.

During the

three

months ended March

31,

2019,

stock options were exercised. During the

three

months ended March

31,

2018

, stock options were exercised for a total of

1,307

shares of common stock.

Stock-based compensation expense recorded under the Incentive Stock Plan

and the

2014

Plan is included in the following line items in the accompanying condensed statements of operations (in thousands):

	Three months ended March 31,
	2019		2018
Research and development	$	433	$	376
General and administrative		857		905
Total stock-based compensation expense		1,290		1,281

There was

stock-based compensation expense related to performance-based awards recognized during the

three

months ended

March 31, 2019

2018