Note 11. Stock Options

The following table summarizes the outstanding stock option activity during the periods indicated:

	Number of shares			Weighted average exercise price		Weighted average remaining contractual term
Balance at December 31, 2015		756,692			2.10		7.60
Granted		359,319			2.60		9.40
Exercised		(58,155	)		2.36		3.50
Expired/Forfeited		(17,469	)		2.13		2.60
Balance at December 31, 2016		1,040,387			2.25		7.80
Granted		420,144		15.11			9.73
Exercised		(211,713	)	2.06			6.14
Expired/Forfeited		(14,719	)		5.80		0.14
Balance at June 30, 2017		1,234,099		6.62			8.31
Vested and exercisable at June 30, 2017		524,065		2.07		6.95
Vested and expected to vest at June 30, 2017		1,234,099		6.62		8.31

The weighted average grant-date fair value of options granted during the six months ended June 30, 2017 and for the year ended December 31, 2016 was $6.19 and $1.23, respectively. For fully vested stock options, the aggregate intrinsic value as of June 30, 2017 and December 31, 2016 was $9,747,000 and $7,770,086, respectively. For stock options expected to vest, the aggregate intrinsic value as of June 30, 2017 and December 31, 2016 was $6,350,728 and $4,569,243, respectively.

During the year ended December 31, 2016, a total of 57,475 shares of restricted common stock with a fair value of $2.00 per share were issued to the Company’s Chief Financial Officer and Chief Operating Officer of which 100% of the shares vested six months after the completion of an initial public offering, or February 2017. The Company recorded $53,056 and $61,894 in expense associated with these shares during the six months ended June 30, 2017 and the year ended December 31, 2016, respectively.

At June 30, 2017 and December 31, 2016 there was $2,821,359 and $522,818, respectively, of total unrecognized compensation cost related to unvested stock options and restricted stock granted under the plans. These costs are expected to be recognized over the next three years and is based on the date the options were granted.

The Company currently uses authorized and unissued shares to satisfy share award exercises.