Annual report pursuant to Section 13 and 15(d)

Property and Equipment - Additional Information (Detail)

v2.4.1.9
Property and Equipment - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Property Plant And Equipment [Abstract]      
Depreciation and amortization $ 0.4us-gaap_DepreciationDepletionAndAmortization $ 0.3us-gaap_DepreciationDepletionAndAmortization $ 0.2us-gaap_DepreciationDepletionAndAmortization