Common Stock (Tables)

12 Months Ended

Dec. 31, 2020

Common Stock

Schedule of shares of common stock reserved for issuance

	December 31,
	2020	2019	2018
Exchange warrants	1,458,000	1,458,000	—
Shares available for future option grants	1,692,753	1,704,183	2,486,637
Outstanding options	6,664,173	5,643,410	3,778,259
Unvested restricted common stock (founders and early exercise of stock options)	—	—	43,076
Shares reserved for employee stock purchase plan	400,000	400,000	400,000
Total	10,214,926	9,205,593	6,707,972