11.Stock Incentive Plans

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

As of September 30, 2018, the Company had reserved 735,635 shares of Common Stock under the 2008 Plan, of which none remained available for future issuance. As of September 30, 2018, the Company had reserved 3,753,822 shares of Common Stock under the 2015 Plan, of which 123,227 shares remained available for future issuance. Under the 2015 Plan, stock options may not be granted with exercise prices at less than fair value on the date of the grant.

Terms of stock option agreements, including vesting requirements, are determined by the Company’s board of directors, subject to the provisions of the applicable stock incentive plan. Options granted by the Company generally vest ratably over four years, with a one-year cliff, and options are exercisable from the date of grant for a period of ten years. For options granted through September 30, 2018 the exercise price or purchase price, as applicable, equaled the estimated fair value of the Common Stock as determined by the Company’s board of directors on the date of grant.

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

	Shares		Weighted- Average Exercise Price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2017	2,845,626		$	4.53	7.75	$	216
Granted	2,133,845		$	0.98
Exercised	(2,917	)	$	1.24
Cancelled or forfeited	(487,097	)	$	2.93
Outstanding at September 30, 2018	4,489,457		$	3.02	8.19	$	102
Vested and Exercisable at September 30, 2018	1,734,044		$	5.24	6.54	$	—

There were no options exercised in the three months ended September 30, 2018 and 2017. The total intrinsic value of options exercised for the nine months ended September 30, 2018 and 2017 was $1 thousand and $41 thousand, respectively. The total fair value of employee and non-employee options vested for the three months ended September 30, 2018 and 2017 was $0.3 million and $0.6 million, respectively. The total fair value of employee and non-employee options vested for the nine months ended September 30, 2018 and 2017 was $1.4 million and $1.8 million, respectively. The weighted-average grant date fair value of options granted to employees and non-employees for the three months ended September 30, 2018 and 2017 was $0.46 and $0.86, respectively. The weighted-average grant date fair value of options granted to employees and non-employees for the nine months ended September 30, 2018 and 2017 was $0.66 and $0.85, respectively.

At September 30, 2018, the total unrecognized compensation expense related to unvested stock option awards was $2.7 million. The Company expects to recognize that cost over a weighted-average period of approximately 1.8 years.