Fair Value Measurement - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Cash equivalents maturity period	Three months or less
License agreement fair value	$ 328	$ 151

Fair value portion of assets, excluding financial assets, that lack physical substance, having a limited useful life.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19190-110258

Name:	us-gaap_FiniteLivedIntangibleAssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant