Short Term Investments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified				6 Months Ended
Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2013 Certificates of Deposit	Sep. 30, 2013 Certificates of Deposit Maturing in December 04 2013	Sep. 30, 2013 Certificates of Deposit Maturing in March 31 2013
Investment [Line Items]
Short-term Investments	$ 15,155	$ 45,235	$ 15,200	$ 10,100	$ 5,100
Certificate of deposit, maturity year and month				Dec. 04, 2013	Mar. 31, 2014

Investments which are intended to be sold in the short term (usually less than one year or the normal operating cycle, whichever is longer) including trading securities, available-for-sale securities, held-to-maturity securities, and other short-term investments not otherwise listed in the existing taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.2)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph g

-Article 7

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