Common stock

As of December 31, 2016, the Company had authorized 100,000,000 shares of common stock, $0.0001 par value per share. Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors. The Company does not intend to declare dividends for the foreseeable future.

Restricted common stock to founders

In March 2014, the Company sold 4,553,415 shares of restricted common stock to the founders of the Company ("recipients"), for $0.0004 per share, for total proceeds of $1,950. In April 2014, based upon anti-dilution provisions granted to the founders, an additional 867,314 shares of restricted common stock were sold to the same founders, after which the anti-dilution provisions were terminated. The restricted common stock vested 25% upon issuance, and the remaining 75% vests ratably over four years, during which time the Company has the right to repurchase the unvested shares held by a recipient if the relationship between such recipient and the Company ceases. If the relationship terminates, the Company has 90 days to repurchase unvested shares at $0.0004. Such shares are not accounted for as outstanding until they vest. There were 4,234,771 shares of restricted common stock outstanding as of December 31, 2016. Unvested restricted common stock awards to non-employees are re-measured at each vest date and each financial reporting date.

The following is a summary of restricted common stock activity:



	Number of Shares		Weighted-Average Grant Date Fair Value
Non-vested at December 31, 2015	2,202,262		$	0.10
Issued	—		—
Vested	(1,016,304	)	0.10
Forfeited	—		—
Non-vested at December 31, 2016	1,185,958		$	0.10

The total fair value of shares vested during the twelve months ended December 31, 2016, the twelve months ended December 31, 2015 and the period from February 26, 2014 (inception) to December 31, 2014 was approximately $9,646,000, $15,616,000 and $3,620,000 respectively.

Restricted common stock to consultants

During the twelve months ended December 31, 2016, the Company issued 18,194 shares of restricted common stock to non-employee consultants and advisors. The Company has the right to repurchase any unvested shares held by a recipient if the relationship between such recipient and the Company ceases. If the relationship terminates, the Company has 90 days to repurchase unvested shares at $0.0001 per share. Such shares are not accounted for as outstanding until they vest. There were 7,360 shares of restricted common stock issued to consultants outstanding as of December 31, 2016. Unvested restricted common stock awards to non-employees are re-measured at each vest date and each financial reporting date.

The following is a summary of restricted common stock activity:



	Number of Shares		Weighted-Average Grant Date Fair Value
Non-vested at December 31, 2015	—		$	—
Issued	18,194		9.51
Vested	(7,360	)	9.19
Forfeited	—		—
Non-vested at December 31, 2016	10,834		$	9.72

The total fair value of shares vested during the twelve months ended December 31, 2016 was $71,000. No shares were issued to consultants during the twelve months ended December 31, 2015 or the period from February 26, 2014 (inception) to December 31, 2014.

Employee stock purchase plan

In 2015, the Company's Board of Directors adopted, and the Company's stockholders approved, the 2015 Employee Stock Purchase Plan ("the ESPP"). As of the December 31, 2016, no shares of common stock have been purchased under the ESPP.

Shares reserved for future issuance

The Company has reserved the following number of shares of common stock for future issuance:



	As of December 31,
	2016	2015
Stock-based compensation awards	2,722,573	2,031,528
Vesting of restricted common stock	1,196,792	2,202,262
Employee stock purchase plan	354,569	175,131
Total	4,273,934	4,408,921