Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Mar. 31, 2013
Revenue:
Product revenue	$ 229,950		$ 183,280	$ 157,614
Funded research and development	361		363	510
Total Revenue	230,311		183,643	158,124
Costs and expenses:
Cost of product revenue	39,945		37,322	31,596
Research and development	35,973		30,707	25,647
Selling, general and administrative	125,727		107,251	84,227
Amortization of intangible assets				111
Costs and Expenses, Total	201,645		175,280	141,581
Income from operations	28,666		8,363	16,543
Other income:
Investment income (expense), net	196		118	(7)
Other (expense) income, net	(97)		49	326
Other income (expense), net	99		167	319
Income (loss) before income taxes	28,765		8,530	16,862
Income tax (benefit) provision	(84,923)	[1]	1,179	1,848
Net income	$ 113,688		$ 7,351	$ 15,014
Basic net income per share	$ 2.80		$ 0.19	$ 0.38
Basic weighted average shares outstanding	40,632		39,334	39,113
Diluted net income per share	$ 2.65		$ 0.18	$ 0.37
Diluted weighted average shares outstanding	42,858		41,606	41,052

[1] Net income for the quarter and year ended March 31, 2015 included an income tax benefit of $84.9 million, primarily due to the release of the valuation allowance on certain deferred tax assets in the quarter ended March 31, 2015.