Annual report pursuant to Section 13 and 15(d)

Net Loss Per Common Share - Additional Information (Detail)

v2.4.1.9
Net Loss Per Common Share - Additional Information (Detail)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]      
Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount 9,058,166us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount 5,090,171us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount 3,371,161us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Restricted Stock [Member]      
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]      
Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount 8,287,384us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= us-gaap_RestrictedStockMember