10.Stock-based compensation

Prior to the Company’s IPO, the Company granted awards to eligible participants under the 2008 equity incentive plan (“2008 Plan”). In June 2015, the Company’s board of directors adopted and the Company’s stockholders approved the 2015 Stock Incentive Plan (“2015 Plan”), which became effective immediately prior to the effectiveness of the Company’s IPO. Subsequent to the Company’s IPO, option grants are awarded to eligible participants only under the 2015 Plan.

The 2015 Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock units, stock appreciation rights and other stock-based awards. The Company’s employees, officers, directors and consultants and advisors are eligible to receive awards under the 2015 Plan. The maximum number of shares of Common Stock that may be delivered in satisfaction of awards under the 2015 Plan is 1,068,287 shares, plus (1) 25,942 shares that were available for grant under the 2008 Plan immediately prior to the closing of the IPO, (2) the number of shares of Common Stock subject to outstanding awards under the 2008 Plan upon closing of the IPO that expire, terminate or are otherwise surrendered, cancelled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right and (3) an annual increase, to be added the first day of each fiscal year, beginning with the fiscal year ending December 31, 2016 and continuing until, and including, the fiscal year ending December 31, 2025, equal to the lowest of 1,297,334 shares of Common Stock, 4% of the number of shares of Common Stock outstanding on the first day of the fiscal year and an amount determined by the Company’s board of directors.

As of September 30, 2015, the Company had reserved 1,466,274 shares of Common Stock under the 2008 Plan, of which none remained available for future issuance. As of September 30, 2015, the Company had reserved 1,106,685 shares of Common Stock under the 2015 Plan, of which 860,948 shares remained available for future issuance.

Stock Options

A summary of the Company’s stock option activity and related information follows:

	Shares		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)	Agregate Intrinsic Value (in thousands)
Outstanding at December 31, 2014	1,226,140		$	4.14	8.15	$	6,579
Granted	550,797		11.69
Exercised	(25,045	)	2.05
Cancelled or forfeited	(39,881	)	5.46

Outstanding at September 30, 2015	1,712,011		$	6.57	8.11	$	4,560

Exercisable at September 30, 2015	755,860		$	3.27	6.89	$	3,659

Vested or expected to vest at September 30, 2015	1,586,233		$	6.30	8.02	$	4,489

The total intrinsic value of options exercised for the three months ended September 30, 2015 and 2014 was $0, and $0.2 million, respectively. The total intrinsic value of options exercised for the nine months ended September 30, 2015 and 2014 was $0.2 million and $0.3 million, respectively.

At September 30, 2015, the total unrecognized compensation expense related to unvested stock option awards, including estimated forfeitures, was $5.2 million. The Company expects to recognize that cost over a weighted-average period of approximately 3.1 years.

Stock-based compensation expense

Total stock-based compensation expense is recognized for stock options granted to employees and non-employees and has been reported in the Company’s statements of operations as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2015		2014		2015		2014

Research and development	$	173	$	100	$	505	$	289
General and administrative	315		132		638		316

Total	$	488	$	232	$	1,143	$	605

Employee Stock Purchase Plan

In June 2015, the Company’s board of directors adopted and the Company’s stockholders approved the 2015 Employee Stock Purchase Plan (the “2015 ESPP”) which became effective upon closing of the Company’s IPO. The 2015 ESPP authorizes the initial issuance of up to a total of 182,352 shares of Common Stock to participating eligible employees. The number of shares increases each January 1, commencing on January 1, 2016 and ending on December 31, 2026, by an amount equal to the lesser of one percent of the Company’s outstanding shares as of the end of the immediately preceding fiscal year, 364,705 shares and any lower amount determined by the Company’s board of directors. As of September 30, 2015 there has been no activity under the 2015 ESPP.