Fair Value of Company's Financial Assets by Level in Fair Value Hierarchy (Detail) - Fair Value, Measurements, Recurring - Money Market Funds - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Assets:
Assets, fair Value	$ 86,871	$ 71,836
Level 1
Assets:
Assets, fair Value	$ 86,871	$ 71,836

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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