Net Loss Per Share - Schedule of Securities Excluded from Calculation of Net (Loss) per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive excluded from computation of earnings per share amount (shares)	13,896,550	15,065,342	14,560,119
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)	0	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	9,357	120,702
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)	10,454,799	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)	1,294,594	1,441,086	2,173,916
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)	2,147,157	2,173,615	824,217