Net Loss Per Common Share - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total antidilutive securities excluded from the computation of earnings per share (in shares)	8,826,211	3,020,129	7,760,047	2,750,452
Convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total antidilutive securities excluded from the computation of earnings per share (in shares)	3,883,251	641,266	3,042,295	559,066
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total antidilutive securities excluded from the computation of earnings per share (in shares)	4,845,186	2,351,490	4,619,920	2,164,269
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total antidilutive securities excluded from the computation of earnings per share (in shares)	97,774	27,373	97,832	27,117