10.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 March 31, 2018, the Company had reserved 832,092 shares of Common Stock under the 2008 Plan, of which none remained available for future issuance. As of March 31, 2018, the Company had reserved 3,783,509 shares of Common Stock under the 2015 Plan, of which 839,975 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 March 31, 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	930,000	$	1.28
Exercised	—	$	—
Cancelled or forfeited	—	$	—

Outstanding at March 31, 2018	3,775,626	$	3.73	8.08	$	1,001

Vested and Exercisable at March 31, 2018	1,573,375	$	5.30	6.72	$	140

The total intrinsic value of options exercised for the three months ended March 31, 2017 was $27 thousand. There were no options exercised in the three months ended March 31, 2018. The total fair value of employee and non-employee options vested was $0.6 million for each of the three months ended March 31, 2018 and 2017, respectively. The weighted-average grant date fair value of options granted to employees and non-employees for the three months ended March 31, 2018 and 2017 was $0.88 and $0.84, respectively.

At March 31, 2018, the total unrecognized compensation expense related to unvested stock option awards was $3.6 million. The Company expects to recognize that cost over a weighted-average period of approximately 2.1 years.