Segment and Enterprise Wide Disclosures - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended					3 Months Ended		6 Months Ended
	Sep. 30, 2012 Segment	Sep. 30, 2012 UNITED STATES	Mar. 31, 2012 UNITED STATES	Sep. 30, 2012 Europe	Mar. 31, 2012 Europe	Sep. 30, 2012 International	Sep. 30, 2011 International	Sep. 30, 2012 International	Sep. 30, 2011 International
Segment Reporting Information [Line Items]
Number of business segments	1
Percentage of total consolidated assets		71.00%	68.00%
Goodwill and intangibles				$ 35.5	$ 37.0
Percentage of total consolidated assets, excluding goodwill and intangibles				8.00%	8.00%
Percentage of total product revenue						6.00%	7.00%	6.00%	7.00%