Net Loss per Share - Schedule of Anti-dilutive Securities Excluded from Diluted Loss Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from diluted earnings per share	17,734,908	18,130,132
Stock options [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from diluted earnings per share	5,943,908	5,006,532
Restricted Stock Units [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from diluted earnings per share		132,600
Warrant [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from diluted earnings per share	11,791,000	12,991,000