CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Feb. 29, 2012	Feb. 28, 2011	Feb. 28, 2010
CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
Product sales	$ 407,029	$ 407,396	$ 307,068
Intellectual property and other revenues	5,075	2,083	710
Sales and revenues	412,104	409,479	307,778
Costs of goods sold	196,446	194,585	154,872
Gross profit on sales and revenues	215,658	214,894	152,906
Operating expenses:
Research and development	100,350	96,370	77,702
Selling, general and administrative	86,706	100,661	85,049
Acquisition termination fee gain	0	(7,700)	0
Restructuring charges	1,973	4,703	2,123
Impairment loss on equity investment (Symwave)	0	3,208	0
Gain on equity investment (Canesta)	0	(320)	0
Revaluation of contingent consideration	(1,365)	(4,206)	0
Impairment losses on intangible assets (Symwave)	0	3,531	0
Settlement charge	0	0	2,019
Income (loss) from operations	27,994	18,647	(13,987)
Interest income	301	659	981
Interest expense	(155)	(153)	(163)
Other income (expense), net	86	(248)	(514)
Income (loss) before income taxes	28,226	18,905	(13,683)
Provision for (benefit from) income taxes	17,564	8,278	(5,705)
Net income (loss)	$ 10,662	$ 10,627	$ (7,978)
Net income (loss) per share:
Basic (in dollars per share)	$ 0.47	$ 0.47	$ (0.36)
Diluted (in dollars per share)	$ 0.46	$ 0.46	$ (0.36)
Weighted average common shares outstanding:
Basic (in shares)	22,695	22,667	22,133
Diluted (in shares)	23,203	23,108	22,133