Net Loss Per Share - Schedule of Securities Excluded from Calculation of Net Loss Per Share (Detail) - shares	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive excluded from computation of earnings per share amount (shares)	15,016,646	14,867,194
Preferred stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive excluded from computation of earnings per share amount (shares)	40,000	40,000
Common stock warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive excluded from computation of earnings per share amount (shares)	0	71,227
2018 Convertible Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive excluded from computation of earnings per share amount (shares)	11,401,284	11,401,284
Common stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive excluded from computation of earnings per share amount (shares)	982,748	1,825,868
Restricted stock awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive excluded from computation of earnings per share amount (shares)	2,592,614	1,528,815