Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 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 June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
Common stock subject to repurchase		30,165		45,000		37,582		45,000
Warrants to purchase common stock		2,797,561		2,719,932		2,797,561		2,758,746
Common stock options		3,017,624		2,131,624		3,017,624		2,131,624
Employee stock purchase plan		19,144		11,785		26,047		16,970
Total excluded securities		5,864,494		4,908,341		5,878,814		4,952,340

Summary of Calculation of Basic and Diluted Net Loss Per Share

The following table sets forth the calculation of basic and diluted net loss per share:

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2018			2017			2018			2017
Net loss attributable to common shareholders for    basic net loss per share	$	(2,303,193	)	$	(1,625,969	)	$	(4,285,980	)	$	(6,678,008	)
Adjustment for loss from change in fair value of warrants		-			(429,702	)		-			(429,702	)
Net loss used for diluted net loss per share	$	(2,303,193	)	$	(2,055,671	)	$	(4,285,980	)	$	(7,107,710	)
Weighted-average shares used to compute basic net loss    per share		16,425,468			15,343,325			15,926,253			14,435,818
Adjustment to reflect assumed exercise of warrants		-			77,629			-			38,815
Weighted-average shares used to compute diluted net loss    per share		16,425,468			15,420,954			15,926,253			14,474,633
Net loss per share attributable to common shareholders:
Basic	$	(0.14	)	$	(0.11	)	$	(0.27	)	$	(0.46	)
Diluted	$	(0.14	)	$	(0.13	)	$	(0.27	)	$	(0.49	)