Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2017

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 to do so would be anti-dilutive:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
Common stock subject to repurchase		45,000		45,000		45,000		45,000
Warrants to purchase common stock		2,797,561		3,323,876		2,771,685		3,323,876
Common stock options		2,131,624		1,275,624		2,131,624		1,275,624
Employee stock purchase plan		7,064		10,938		7,064		10,938
Total excluded securities		4,981,249		4,655,438		4,955,373		4,655,438