Total Revenue by Geography (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Segment Reporting Information [Line Items]
Total revenue	$ 84,545	$ 72,624	$ 160,906	$ 135,920
United States
Segment Reporting Information [Line Items]
Total revenue	66,616	55,296	121,711	101,536
Europe
Segment Reporting Information [Line Items]
Total revenue	8,001	7,239	18,433	14,839
Asia
Segment Reporting Information [Line Items]
Total revenue	4,206	4,217	8,477	8,475
Rest Of The World
Segment Reporting Information [Line Items]
Total revenue	$ 5,722	$ 5,872	$ 12,285	$ 11,070