Commitments and Contingencies - Additional Information (Detail) (Menlo Park, California [Member], USD $) In Millions, unless otherwise specified	1 Months Ended
Mar. 31, 2014 sqft	Mar. 31, 2015
Menlo Park, California [Member]
Loss Contingencies [Line Items]
Operating facility lease area	12,943
Operating facility lease term	39 months
Total obligation under lease		$ 1.9

Term of the lessee's leasing arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration