Fair Value of Financial Instruments - Additional Information (Detail) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Recurring Fair Value Measurements [Member]
Fair Value Measurement [Line Items]
Liabilities measured at fair value on recurring basis	$ 0	$ 0

Fair value of financial and nonfinancial obligations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

Name:	us-gaap_LiabilitiesFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant