Condensed Consolidated Statements of Comprehensive Loss(Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Condensed Consolidated Statements of Comprehensive Loss [Abstract]
Net loss	$ (21,557)	$ (1,152)	$ (44,947)	$ (8,029)
Other comprehensive gain (loss), net of tax:
Loss on foreign currency translation	(6)	(108)	(122)	(199)
Unrealized gain (loss) on investments	1,358	(2,176)	855	(1,724)
Other comprehensive gain (loss), net of tax	1,352	(2,284)	733	(1,923)
Total comprehensive loss	$ (20,205)	$ (3,436)	$ (44,214)	$ (9,952)