Common Stock (Tables)

3 Months Ended

Mar. 31, 2019

Common Stock

Schedule of shares of common stock reserved for issuance

	March 31,	December 31,
	2019	2018
Shares available for future option grants	3,391,001	2,486,637
Outstanding options	4,040,925	3,778,259
Unvested restricted common stock (founders and early exercise of stock options)	27,073	43,076
Shares reserved for employee stock purchase plan	400,000	400,000
Total	7,858,999	6,707,972