Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2018

Accounting Policies [Abstract]

Summary of Outstanding Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share

For the periods presented, the following table sets forth the outstanding potentially dilutive securities that have been excluded from the calculation of diluted net loss per share because their inclusion would be anti-dilutive:

	Three Months Ended March 31,
	2018		2017
Common stock subject to repurchase		45,000		45,000
Warrants to purchase common stock		2,797,561		2,797,561
Common stock options		2,811,624		1,925,624
Employee stock purchase plan		6,902		5,185
Total excluded securities		5,661,087		4,773,370