Components of Net Deferred Tax Assets (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012
Assets:
Accrued expenses	$ 5,290	$ 3,841
Depreciation	0	1,333
Deferred revenue	6,752	5,743
Reserves	1,325	892
Net operating loss carryforwards	26,096	22,622
Tax credit carryforwards	2,284	1,994
Share-based compensation	1,550	760
Auction rate securities temporary impairment	0	73
Other	352	264
Deferred tax assets, net	43,649	37,522
Liabilities:
Intangible assets	(21,934)	(13,274)
Valuation allowance	(3,795)	(3,529)
Depreciation	(113)	0
Deferred tax assets (liabilities), net	$ 17,807	$ 20,719