Common Stock (Tables)

12 Months Ended

Dec. 31, 2019

Common Stock

Schedule of reserved shares of common stock for issuance

	As of December 31,
	2019	2018
Options outstanding	2,898,977	4,496,557
Unvested restricted stock units outstanding	12,639,066	12,303,913
Shares available for grant under the 2014 equity plan and 2015 inducement plan	1,301,881	2,337,545
Shares available for purchase under the Employee Stock Purchase Plan	378,525	364,762
Total	17,218,449	19,502,777