Condensed Consolidated Statements of Income (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Revenues:
Product revenues	$ 51,661	$ 45,773	$ 151,611	$ 128,553
Contract revenues	397	544	1,102	2,432
Total revenues	52,058	46,317	152,713	130,985
Operating expenses:
Cost of product revenues	9,195	8,853	26,480	25,927
Research and development	9,611	8,180	29,582	23,953
Selling and marketing	20,157	17,336	61,220	52,868
General and administrative	9,696	8,561	29,904	25,640
Total operating expenses	48,659	42,930	147,186	128,388
Income from operations	3,399	3,387	5,527	2,597
Interest income	77	55	217	174
Other income (expense), net	(113)	13	(191)	14
Income before income taxes	3,363	3,455	5,553	2,785
Income tax expense (benefit)	138	(215)	266	182
Net income	$ 3,225	$ 3,670	$ 5,287	$ 2,603
Basic net income per share (in dollars per share)	$ 0.11	$ 0.13	$ 0.18	$ 0.09
Diluted net income per share (in dollars per share)	$ 0.10	$ 0.12	$ 0.17	$ 0.09
Shares used in computing basic net income per share (in shares)	29,491	28,832	29,311	28,784
Shares used in computing diluted net income per share (in shares)	30,808	29,584	30,661	29,625