Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2017

Accounting Policies [Abstract]

Schedule of employee stock-based compensation expense

The stock-based compensation expense recorded for the three and six months ended June 30, 2017 and 2016 is as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2017		2016		2017		2016
Research and development	$	90	$	87	$	184	$	174
General and administrative		721		255		1,688		1,299
Total stock-based compensation expense	$	811	$	342	$	1,872	$	1,473

Schedule of outstanding potentially dilutive securities calculation of diluted loss per share attributable to common stockholders

The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted loss per share attributable to common stockholders (in common stock equivalent shares):

	June 30,
	2017		2016
Series A convertible preferred stock		—		400,000
Series B convertible preferred stock		—		454,581
Convertible promissory notes		—		533,031
Common stock purchase warrants		829,285		710,487
Restricted stock units		386,649		—
Common stock options		1,603,800		1,556,867
Total		2,819,734		3,654,966