Marketable Securities in Unrealized Loss Position (Detail) $ in Thousands	Dec. 31, 2015 USD ($)
Investments Unrealized Loss Position [Line Items]
Aggregate Fair Value	$ 5,100
Unrealized Losses	(3)
Corporate debt securities \| Due within 1 year
Investments Unrealized Loss Position [Line Items]
Aggregate Fair Value	4,100
Unrealized Losses	(3)
Government agency securities \| Due within 1 year
Investments Unrealized Loss Position [Line Items]
Aggregate Fair Value	$ 1,000

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

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