Reconciliation of Income Tax Rate (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2013	Mar. 31, 2012
Reconciliation Of Income Taxes [Line Items]
Pretax Income (Loss)	$ (4,238)	$ 7,308	$ (11,944)
Tax at federal statutory rate	(1,441)	2,485	(4,061)
State tax, net of federal tax benefit	(151)	563	(855)
Share-based compensation expense	(314)	(593)	181
Tax credits		(459)	(140)
Change in valuation allowance	1,934	(2,534)	5,409
Change in unrecognized tax benefit	150	518
Other	(178)	20	(534)
Income Tax Reconciliation Adjustments Net, Total
Tax at federal statutory rate	34.00%	34.00%	34.00%
State tax, net of federal tax benefit	3.56%	7.70%	7.16%
Share-based compensation expense	7.41%	(8.11%)	(1.52%)
Tax credits	0.00%	(6.28%)	1.17%
Change in valuation allowance	(45.63%)	(34.67%)	(45.28%)
Change in unrecognized tax benefit	(3.54%)	7.09%	0.00%
Other	4.20%	0.27%	4.47%
Effective Income Tax Rate Reconciliation Unrecognized Tax Positions Net	0.00%	0.00%	0.00%