Net loss per share (Tables)

12 Months Ended

Dec. 31, 2015

Earnings Per Share [Abstract]

Schedule of Potentially Dilutive Securities Outstanding Excluded from Computations of Diluted Weighted-Average Shares Outstanding

The following potentially dilutive securities outstanding have been excluded from the computations of diluted weighted-average shares outstanding because such securities have an antidilutive impact due to losses reported (in Common Stock equivalent shares):

	As of December 31,
	2015	2014
Convertible preferred stock	2,462,162	—
Warrants issued to 2010/2012 convertible note holders to purchase common stock	480,147	523,867
Options to purchase common stock	1,858,839	1,072,011
Warrants issued in 2009 to purchase common stock	9,259	9,259
Warrants issued to underwriter to purchase common stock	82,500	82,500
Series A warrants to purchase common stock	2,425,605	2,449,605
Series B warrants to purchase common stock	116,580	2,449,605
Series C warrants to purchase common stock	590,415	—
Series D warrants to purchase common stock	1,280,324	—