Restructuring Charges - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Employee	Dec. 31, 2012 Severance	Sep. 30, 2012 Severance	Dec. 31, 2012 Severance
Restructuring Cost and Reserve [Line Items]
Restructuring program number of positions eliminated or moved					12
Restructuring charges related to severance costs					$ 603
Restructuring charges to operations	$ (1)	$ 372	$ 1,065	$ 372		$ (1)	$ 1,200	$ 1,140