Future Amortization Expenses for Intangible Assets and Patents Excluding Patents Pending (Parenthetical) (Detail) (USD $)	Mar. 31, 2013	Mar. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Patent pending costs	$ 15,176,000	$ 15,132,000
Patents pending
Finite-Lived Intangible Assets [Line Items]
Patent pending costs	$ 672,000	$ 673,000

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

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