Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Revenue:
Product revenue	$ 157,614	$ 125,286	$ 99,837
Funded research and development	510	1,089	1,314
Total Revenue	158,124	126,375	101,151
Costs and expenses:
Cost of product revenue	31,596	24,507	21,977
Research and development	25,647	27,159	26,677
Selling, general and administrative	84,227	71,711	62,287
Amortization of intangible assets	111	1,478	1,395
Costs and Expenses, Total	141,581	124,855	112,336
Income (loss) from operations	16,543	1,520	(11,185)
Other income:
Investment (expense) income, net	(7)	(3)	9
Gain on sale of WorldHeart stock			456
Gain on settlement of investment		1,017
Other income (expense), net	326	9	(143)
Other income (expense), net	319	1,023	322
Income (loss) before income tax provision	16,862	2,543	(10,863)
Income tax provision	1,848	1,048	892
Net income (loss)	$ 15,014	$ 1,495	$ (11,755)
Basic net income (loss) per share	$ 0.38	$ 0.04	$ (0.32)
Basic weighted average shares outstanding	39,113	38,374	37,167
Diluted net income (loss) per share	$ 0.37	$ 0.04	$ (0.32)
Diluted weighted average shares outstanding	41,052	40,172	37,167